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linux/fs/binfmt_elf.c
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Linus Torvalds ed3b875bea Merge tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 
Pull MM updates from Andrew Morton:

 - "mm: drop "sub" prefix from various places" (Dev Jain)

   page->folio conversion and a naming cleanup

 - "mm/kasan: remove redundant initialization for kasan_flag_write_only"
   (Igor Putko)

   KASAN cleanup work

 - "mm/filemap: reduce unnecessary xarray lookups" (Chi Zhiling)

   Small speedup in the pagecaache read code

 - "mm/percpu: Fix possible NOFS/NOIO reclaim recursion" (Kaitao Cheng)

   Improve the vmalloc code - mainly the avoidance of GFP_KERNEL
   allocations when the caller asked for GFP_NOFS or GFP_NOIO

 - "mm/kmemleak: avoid soft lockup when scanning task stacks" (Breno
   Leitao)

   Avoid a soft lockup watchdog trigger from the kmemleak scanning code
   in extreme situations

 - "mm/page_owner: misc cleanups" (Ye Liu)

   Cleanups to the page_owner code. For some reason lots of people have
   been working on the page_owner code this cycle.

 - "mm: convert to walk_page_range_vma() to eliminate find_vma()"
   (Kefeng Wang)

   Simplify and accelerate the page walking library function

 - "mm/migrate: preparatory cleanups for batch copy and offload"
   (Shivank Garg)

   Cleanups in the migration code

 - "mm/page_owner: add per-fd filter infrastructure for print_mode and
   NUMA filtering" (Zhen Ni)

   Per-fd filtering to page_owner in order to reduce the sometimes vast
   amount of output it can produce

 - "mm: Refactor bootmem gigantic hugepage allocation" (Muchun Song)

   Fixes and preparatory cleanups around bootmem HugeTLB handling,
   sparse initialization ordering, and related vmemmap setup

 - "mm/zsmalloc: reduce lock contention in zs_free()" (Wenchao Hao)

   Reduce lock contention in zs_free(), which dominates the unmap path
   under memory pressure on Android (LMK kills) and on x86 servers
   running zswap-heavy workloads.

   Up to 1.83x improvement in microbenchmarking.

 - "move alloc_tag.c file under mm/" (Suren Baghdasaryan)

 - "samples/damon: handle damon_{start,stop}() failures" (SJ Park)

   Fix improper handling of damon_start(), damon_stop(), and
   damon_call() failures across DAMON sample modules to prevent
   potential memory leaks, operation disruptions and use-after-free
   bugs

 - "mm/damon/sysfs: kobject_del() directories that users can
   create/remove" (SJ Park)

   Fix delayed sysfs directory removal under DEBUG_KOBJECT_RELEASE
   causeing creation failures due to duplicate directory names by adding
   missing kobject_del() calls before creating new directories

 - "mm: cleanup clear_not_present_full_ptes()" (David Hildenbrand)

   Clean up the core pte handling code

 - "selftests/damon: misc fixes for test bugs" (Kunwu Chan)

   Fix several bugs in the DAMON selftests

 - "selftests/damon: fix memcg_path staging handling" (Cheng Nie)

   Fix a bug in _damon_sysfs.py for damos_filter memcg_path setup, and
   add a test case for it in sysfs.py.

 - "selftests/damon: test kdamond refresh_ms" (Ruslan Valiyev)

   Selftest coverage for DAMON's refresh_ms sysfs feature by updating
   the test control module and verifying that scheme stats update
   automatically without manual intervention

 - "mm/damon: five misc fixups" (Akinobu Mita)

   Miscellaneous DAMON fixups.

 - "mm/damon/core: detect internal variation above max_nr_regions/2"
   (Jiayuan Chen)

   Fix DAMON's region splitting behavior when region counts exceed half
   the maximum budget by dynamically scaling down the split fraction as
   the limit approaches, preventing large regions from staying un-split,
   and add corresponding KUnit test coverage

 - "mm: preparatory patches for PMD level swap entries" (Usama Arif)

   Refactor and clean up PMD softleaf helpers, call sites, and
   architecture flags to lay the groundwork for a follow-up series that
   introduces PMD page table swap entries

 - "mm/damon: update, optimize, and clean up doc, tests, and code" (SJ
   Park)

   Update DAMON design and ABI documentation, expands unit and selftest
   coverage, optimize damon_commit_target_regions(), and clean up
   recently added sysfs interface code for better readability

 - "mm/vmpressure: reduce CPU, memory and code overhead on cgroup v2"
   (Usama Arif)

   Optimize vmpressure() by skipping unnecessary work on cgroup v2 for
   userspace event notifications and refactor v1-only eventfd handling
   into mm/memcontrol-v1.c to reduce memory overhead and code complexity

 - "selftests/mm: refactor pkey helpers and fix mmap error handling"
   (Hongfu Li)

   Refactor pkeys shared tracing and assertion helpers into a common
   file, unify protection key selftests to use consistent diagnostic
   logging and assertions, and enforce standardized MAP_FAILED return
   checks for mmap() calls across the tests

 - "mm/damon: optimize out nr_accesses_bp" (SJ Park)

   Replace the error-prone, continuously updated nr_accesses_bp field in
   damon_region with an on-demand moving sum function, reducing
   structure memory overhead and avoiding state corruption bugs

 - "Open HugeTLB allocation routine for more generic use" (Ackerley Tng)

   Decouple HugeTLB folio allocation from VMA dependencies by
   introducing hugetlb_alloc_folio(), enabling subsystems like
   guest_memfd to allocate HugeTLB folios without standard VMA
   reservations or pseudo-VMAs

 - "mm/damon: provide pseudo moving sum probe_hits" (SJ Park)

   Integrate DAMON's probe_hits attribute counter into the pseudo moving
   sum infrastructure, enabling real-time, online monitoring without
   waiting for full aggregation intervals

 - "mm: Some cleanups for page allocator APIs" (Brendan Jackman)

   Simplify and refactor the page allocator entry points and flags by
   unifying allocation paths, adding internal alloc_flags arguments, and
   eliminating redundant __ prefixed alloc_pages variants.

 - "Fix incorrect access of hugetlb pte entries" (Dev Jain)

   Enforce the consistent use of huge_ptep_get() instead of ptep_get()
   for HugeTLB entries and fixes an unaligned address issue in arm64's
   huge_ptep_get() implementation

 - "mm/damon: validate all parameters in the core" (SJ Park)

   Consolidate parameter validation into the DAMON core specifically
   within damon_start() and damon_commit_ctx() to centralize error
   checking, eliminate caller-side redundant checks and to improve
   maintenance efficiency

 - "tools/mm/page_owner_sort: fix filtering and cleanup issues" (Yichong
   Chen)

   Rename is_need() to filter_record() for clearer return semantics, fix
   per-record allocation memory leaks and bound output copies in
   search_pattern() to address an existing buffer issue

 - "memcg: bail out reclaim when memcg is dying" (Jiayuan Chen)

   Mitigate a system-wide stall which occurs when a cgroup is removed
   while one of its memory control files is doing synchronous reclaim

 - "mm/memory-failure: add panic option for unrecoverable pages" (Breno
   Leitao)

   Introduce an opt-in vm.panic_on_unrecoverable_memory_failure sysctl
   that immediately panics the kernel on unrecoverable memory errors in
   kernel-owned pages to preserve error context and prevent delayed,
   silent data corruption

 - "mm/damon: refactor damon_{start,stop,commit}() for simple error
   handling" (SJ Park)

   Refactor the DAMON core API functions to guarantee that all contexts
   are fully stopped when damon_start(), damon_stop(), or damon_commit()
   fail, eliminating the need for complex and error-prone caller-side
   cleanup code

 - "Keep tail page private zero at free and folio split" (Zi Yan)

   Add checks to ensure tail_page->private is zero when freeing compound
   or high-order pages and when promoting tail pages during large folio
   splits. By validating these fields at free and split time, it allows
   the removal of redundant private field clearing inside
   prep_compound_tail()

 - "mm: drop redundant lru_add_drain in anon folio reuse paths" (Barry
   Song)

   Eliminate redundant lru_add_drain() calls in
   wp_can_reuse_anon_folio() and do_swap_page() to reduce LRU lock
   contention and system overhead

   By validating folio refcounts against the LRU cache before draining
   and removing unnecessary drains in the swap path, it achieves up to a
   30.5% reduction in drain calls during heavy swap workloads

 - "mm: clean up folio LRU and swap declarations" (Jianyue Wu)

   Reorganize folio LRU and swap code by relocating page-cluster state
   to mm/swap_state.c, renaming mm/swap.c to mm/folio.c, and moving
   MM-internal reclaim declarations into mm/internal.h.

 - "userfaultfd: working set tracking for VM guest memory" (Kiryl
   Shutsemau)

   Add userfaultfd support for tracking the working set of VM guest
   memory, so a VMM can identify hot pages and reclaim cold ones to
   tiered or remote storage

 - "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 2)" (David
   Hildenbrand)

   Remove the remaining pieces of CONFIG_HAVE_BOOTMEM_INFO_NODE,
   performing some smaller cleanups around freeing of reserved vmemmap
   pages on the way.

 - "mm/damon: update probe hits for runtime parameter commits" (SJ Park)

   Ensure that DAMON's probe_hits attribute counter is properly updated
   when monitoring intervals are changed at runtime, matching the
   behavior of nr_accesses. To achieve this, it refactors and renames
   existing helper functions for shared use, applies the updates to
   probe_hits, and handles edge cases in damon_probe_hits_mvsum() to
   maintain measurement accuracy.

 - "KSM: performance optimizations for rmap_walk_ksm" (xu xin)

   Resolve a severe KSM reverse-mapping performance bottleneck where
   thousands of split VMAs sharing a single anon_vma cause extended lock
   contention.

   By adding an interval-filtering check during the rmap walk, it
   reduces worst-case anon_vma lock hold times from over 500ms down to
   under 2ms, preventing application freezes and latency spikes under
   memory pressure.

 - "mm: split a couple of headers from internal.h" (Mike Rapoport)

   Split declarations related to mm_init, memblock, vmalloc and sparse
   into new headers

 - "KSM: use linear_page_index in collect_procs_ksm()" (xu xin)

   Apply the interval tree optimization from rmap_walk_ksm() to
   collect_procs_ksm() to avoid iterating over non-matching VMAs during
   KSM memory error handling.

   It hoists loop-invariant address initialization and restricts the
   anon_vma_interval_tree_foreach walk to a targeted page offset range,
   reducing redundant checks and improving lookup efficiency.

 - "selftests/mm: avoid false failures in hugetlb and KSM tests" (Sayali
   Patil)

   Fix issues in the hugetlb and KSM MM selftest categories that can
   report failures when the prerequisites for the tests are not
   satisfied

 - "mm/damon: introduce data attributes only monitoring" (SJ Park)

   Introduce attribute-weighted region management in DAMON, allowing
   users to prioritize specific data attributes (such as page sizes or
   cgroups) over or instead of access monitoring.

   By assigning weights to attribute probes, DAMON can completely
   disable access tracking and adjust monitoring regions based on
   weighted probe-hit counters to optimize monitoring quality for
   attribute-focused workloads.

 - "mm/hmm: Add mmap lock-drop support for userfaultfd-backed mappings"
   (Stanislav Kinsburskii)

   Extend hmm_range_fault() to support userfaultfd-backed regions by
   allowing the mmap lock to be dropped during fault handling via a new
   hmm_range_fault_locked() helper.

   By accepting a locked pointer and signaling retry status when lock
   release occurs, it enables page fault resolution in userfaultfd
   regions while preserving backward compatibility for existing callers.

 - "mm: make VMA page offset handling more consistent" (Lorenzo Stoakes)

   Clean up and standardize how vma->vm_pgoff is accessed and
   manipulated across file-backed and anonymous mappings in the kernel

   It introduces dedicated helper functions such as vma_start_pgoff(),
   vma_end_pgoff(), vma_set_pgoff() and linear_page_delta() while
   renaming rmap interval tree helpers to better reflect their
   functionality.

   These changes establish a cleaner foundation for future work that
   will unify virtual page offset indexing for all anonymous and CoW'd
   folios.

 - "mm: handle device-private PMDs in walk callbacks" (Usama Arif)

   Address kernel panics and state corruption caused by MM walk
   callbacks reaching non-present device-private PMD swap entries
   created during HMM migrations

   It ensures that functions which acquire pmd_trans_huge_lock()
   properly recognize device-private PMDs instead of assuming a present
   THP or a standard migration entry.

 - "mm/rmap: Refactor try_to_unmap_one" (Dev Jain)

   Refactor try_to_unmap_one by modularizing Hugetlb,
   anonymous-lazyfree, and anonymous-swapbacked logic into dedicated
   functions, laying the structural groundwork for batched anonymous
   large folio unmapping.

 - "Docs/ABI/damon: sysfs ABI document fixes and additions" (Song Hu)

   Fix typos and fills in missing entries in the DAMON sysfs ABI
   document

 - "dax/kmem: atomic whole-device hotplug via sysfs" (Gregory Price)

   Introduce an atomic sysfs state attribute and supporting DAX/MM
   infrastructure to prevent userland races when offlining and removing
   entire memory regions

   By adding an unplugged state alongside standard online modes, it
   enables whole-device atomic hotplug control while preserving backward
   compatibility.

 - "mm: convert more vm_flags_t users to vma_flags_t" (Lorenzo Stoakes)

   Continue transitioning the kernel from the deprecated vm_flags_t type
   to vma_flags_t across core memory management infrastructure.

   It replaces legacy type usage in core functions such as do_mmap(),
   unmapped area allocation, mm->def_vma_flags, and VMA operations like
   mlock, mprotect, and mremap.

 - "Two small patches to clean up mm/mm_slot.h" (xu xin)

   Refactor mm_slot.h by introducing mm_slot_remove() to unify duplicate
   slot deletion sequences in khugepaged and KSM. It also adds code
   documentation explaining why mm_slot_lookup and mm_slot_insert must
   remain as preprocessor macros rather than static inline functions.

 - "mm/damon/core: hide core-private struct fields" (SJ Park)

   Clean up DAMON core structures by consistently marking internal-only
   fields with private: comment tags to prevent improper direct access
   from outer layers.

   It enforces encapsulation across core structures including
   damon_region, damon_target, and damon_ctx and updates DAMON_SYSFS to
   interact through approved access APIs instead of exposing raw struct
   members.

 - "mm/damon: unurgent fixes for infinite loop, NULL de-ref and races"
   (SJ Park)

   Address potential infinite loops, NULL dereferences, and race
   conditions identified in DAMON

   It fixes an infinite loop triggered by extreme user configurations, a
   NULL pointer dereference within unit tests and minor monitoring
   accuracy degradation caused by subtle runtime races.

 - "mm/page_alloc: fixes for free_pages_nolock() on RT/UP" (Brendan
   Jackman)

   Fix an NMI safety flaw in __free_frozen_pages() where freeing pages
   on non-SMP or PREEMPT_RT kernels can bypass can_spin_trylock() checks
   via non-PCP or isolated migration paths.

   It also resolves potential kernel crashes and privilege escalation
   risks triggered when BPF tracing runs in NMI context alongside memory
   hotplug or large allocation frees.

 - "mm/page_alloc: couple of followups for recent cleanups" (Brendan
   Jackman)

   Clean up and update page allocator nomenclature, documentation, and
   debug assertions.

   It aligns internal FPI_ flags with the public "nolock" naming
   convention, removes outdated internal implementation details from
   high-level page allocator comments, and eliminates obsolete
   VM_BUG_ON() assertions in allocation paths.

 - "mm/mseal: further cleanups" (Lorenzo Stoakes)

   Refactor and simplify the mseal implementation by clarifying API
   boundaries and removing unnecessary code complexity.

   It replaces generic do_mseal() usage outside the syscall with a
   dedicated mseal_mmap_page_zero() helper for MMAP_PAGE_ZERO,
   eliminates mm_struct parameters to enforce that sealing applies only
   to current->mm, and streamlines overall logic and comments with no
   functional changes intended.

 - "mm/vmscan: fix swappiness=max and clean up per-node proactive
   reclaim" (Ridong Chen)

   Resolve reclaim behavior bugs and clean up function parameters across
   memory reclaim paths

   It fixes swappiness=max in both standard reclaim and MGLRU so
   unswappable anonymous memory no longer falls back to evicting page
   cache, ensures reclaim_store() returns accurate error codes instead
   of collapsing all failures into -EAGAIN, and removes the obsolete
   gfp_mask parameter from __node_reclaim().

 - "mm: mincore: misc cleanups" (Kefeng Wang)

   Clean up and simplifies the mincore code. Most importantly, it
   removes the historical special behavior that always reports VM_PFNMAP
   pages as non-resident.

 - "mm/huge_memory: drop dead split helper variants" (Kiryl Shutsemau)

   Two trivial cleanups in the folio split API

 - "mm/damon: fix uninitialized DAMOS field and kunit exec expectation
   bugs" (SJ Park)

   Resolve minor operational and testing bugs in DAMON identified by
   Sashiko. It initializes the damos->last_applied field to prevent
   occasional efficiency degradation and fixes invalid memory accesses
   in DAMON KUnit tests during test failure handling.

 - "cleanup for stable_page_flags()" (Jinjiang Tu)

   Clean up and refactor stable_page_flags() used by /proc/kpageflags
   without altering functionality.

   It uses BIT_ULL() to prevent shift-overflow warnings on 64-bit flag
   bits, converts folio-specific flag checks to standard folio_test_*()
   helpers, and removes redundant CONFIG_PAGE_IDLE_FLAG handling.

 - "Batch unmap of uffd-wp file folios" (Dev Jain)

   Extend batched folio unmapping support to file folios within
   userfaultfd write-protect (uffd-wp) VMAs by adding batching
   capabilities to pte_install_uffd_wp_if_needed().

   This removes special-case restrictions on uffd-wp VMAs in
   try_to_unmap_one(), significantly simplifying the function's control
   flow and complexity.

 - "mm/early_ioremap: clarify and clean up early_ioremap_reset()"
   (Sang-Heon Jeon)

   Clarify and clean up the architecture-specific usage of
   __late_set_fixmap() and __late_clear_fixmap() after
   early_ioremap_reset()

   It adds explicit documentation regarding when early_ioremap_reset()
   must be called and removes redundant macro definitions and reset
   calls in the RISC-V and ARM64 architectures.

 - "mm: fix reclaim storms in defrag_mode" (Johannes Weiner)

   Address severe performance regressions, swap storms, and spurious
   OOMs caused by vm.defrag_mode=1 under high memory pressure in Meta
   production

   It updates the page allocator slowpath so non-movable allocation
   requests actively trigger direct reclaim and direct compaction at
   pageblock_order scale, allowing them to claim whole pageblocks rather
   than spinning unproductively.

 - "zram: lockmap tweaks" (Sebastian Siewior)

   Optimize and fix lockdep tracking for zram devices by consolidating
   per-entry lockmaps and isolate lock classes across multiple instances

   This reduces memory overhead by replacing per-entry lockdep_map
   instances with a single map per struct zram, and assigns a dynamic
   lock_class_key to each instance to prevent false deadlock reports
   when different zram devices are backed by distinct filesystems.

* tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (501 commits)
  selftests/mm: thuge-gen: fix test_shmget() for PAGE_SIZE check
  selftests/mm: unpoison pages in memory-failure teardown
  mm/shmem: downgrade final i_blocks check in shmem_evict_inode() to pr_warn()
  mm/khugepaged: replace mutex_lock/mutex_unlock usage with guard macro
  mm/zsmalloc: fix release order of locks in zs_page_migrate()
  Documentation: zram: remove sections numbering
  ksm: stop iterating VMAs when ksm_test_exit returns true
  mm: fold userfaultfd_rwp() to false without CONFIG_ARCH_HAS_PTE_PROTNONE
  mm/migrate: report RCU-tasks quiescent states in migrate_pages_batch()
  zram: use a custom key for each zram object
  zram: move lockmap to be per-zram instead per table
  selftests/mm: fix gup_longterm EINVAL error message
  mm: page_alloc: fix non-movable reclaim storm in defrag_mode
  mm: page_alloc: move capture_control to the page allocator
  mm: compaction: support non-movable compaction for pageblock requests
  mm: page_alloc: __GFP_FS lockdep annotation for direct compaction
  hugetlb: evaluate subpool free state while locked
  mm/damon: remove trailing semicolons after function definitions
  mm/damon/ops-common: prevent migration fallback to non-target nodes
  mm/damon: update outdated comment about DAMOS filter handling
  ...
2026-08-20 18:17:08 -07:00

2145 lines
57 KiB
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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/binfmt_elf.c
*
* These are the functions used to load ELF format executables as used
* on SVr4 machines. Information on the format may be found in the book
* "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
* Tools".
*
* Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/log2.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/personality.h>
#include <linux/elfcore.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/compiler.h>
#include <linux/highmem.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
#include <linux/security.h>
#include <linux/random.h>
#include <linux/elf.h>
#include <linux/elf-randomize.h>
#include <linux/utsname.h>
#include <linux/coredump.h>
#include <linux/sched.h>
#include <linux/sched/coredump.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/cputime.h>
#include <linux/sizes.h>
#include <linux/types.h>
#include <linux/cred.h>
#include <linux/dax.h>
#include <linux/uaccess.h>
#include <uapi/linux/rseq.h>
#include <linux/rseq.h>
#include <asm/param.h>
#include <asm/page.h>
#ifndef ELF_COMPAT
#define ELF_COMPAT 0
#endif
#ifndef user_long_t
#define user_long_t long
#endif
#ifndef user_siginfo_t
#define user_siginfo_t siginfo_t
#endif
/* That's for binfmt_elf_fdpic to deal with */
#ifndef elf_check_fdpic
#define elf_check_fdpic(ex) false
#endif
static int load_elf_binary(struct linux_binprm *bprm);
/*
* If we don't support core dumping, then supply a NULL so we
* don't even try.
*/
#ifdef CONFIG_ELF_CORE
static int elf_core_dump(struct coredump_params *cprm);
#else
#define elf_core_dump NULL
#endif
#if ELF_EXEC_PAGESIZE > PAGE_SIZE
#define ELF_MIN_ALIGN ELF_EXEC_PAGESIZE
#else
#define ELF_MIN_ALIGN PAGE_SIZE
#endif
#ifndef ELF_CORE_EFLAGS
#define ELF_CORE_EFLAGS 0
#endif
#define ELF_PAGESTART(_v) ((_v) & ~(int)(ELF_MIN_ALIGN-1))
#define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
#define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
static struct linux_binfmt elf_format = {
.module = THIS_MODULE,
.load_binary = load_elf_binary,
#ifdef CONFIG_COREDUMP
.core_dump = elf_core_dump,
.min_coredump = ELF_EXEC_PAGESIZE,
#endif
};
#define BAD_ADDR(x) (unlikely((unsigned long)(x) >= TASK_SIZE))
static inline void elf_coredump_set_mm_eflags(struct mm_struct *mm, u32 flags)
{
#ifdef CONFIG_ARCH_HAS_ELF_CORE_EFLAGS
mm->saved_e_flags = flags;
#endif
}
static inline u32 elf_coredump_get_mm_eflags(struct mm_struct *mm, u32 flags)
{
#ifdef CONFIG_ARCH_HAS_ELF_CORE_EFLAGS
flags = mm->saved_e_flags;
#endif
return flags;
}
/*
* We need to explicitly zero any trailing portion of the page that follows
* p_filesz when it ends before the page ends (e.g. bss), otherwise this
* memory will contain the junk from the file that should not be present.
*/
static int padzero(unsigned long address)
{
unsigned long nbyte;
nbyte = ELF_PAGEOFFSET(address);
if (nbyte) {
nbyte = ELF_MIN_ALIGN - nbyte;
if (clear_user((void __user *)address, nbyte))
return -EFAULT;
}
return 0;
}
/* Let's use some macros to make this stack manipulation a little clearer */
#ifdef CONFIG_STACK_GROWSUP
#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
#define STACK_ROUND(sp, items) \
((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
#define STACK_ALLOC(sp, len) ({ \
elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
old_sp; })
#else
#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
#define STACK_ROUND(sp, items) \
(((unsigned long) (sp - items)) &~ 15UL)
#define STACK_ALLOC(sp, len) (sp -= len)
#endif
#ifndef ELF_BASE_PLATFORM
/*
* AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
* If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
* will be copied to the user stack in the same manner as AT_PLATFORM.
*/
#define ELF_BASE_PLATFORM NULL
#endif
static int
create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec,
unsigned long interp_load_addr,
unsigned long e_entry, unsigned long phdr_addr)
{
struct mm_struct *mm = current->mm;
unsigned long p = bprm->p;
int argc = bprm->argc;
int envc = bprm->envc;
elf_addr_t __user *sp;
elf_addr_t __user *u_platform;
elf_addr_t __user *u_base_platform;
elf_addr_t __user *u_rand_bytes;
const char *k_platform = ELF_PLATFORM;
const char *k_base_platform = ELF_BASE_PLATFORM;
unsigned char k_rand_bytes[16];
int items;
elf_addr_t *elf_info;
int ei_index;
const struct cred *cred = current_cred();
struct vm_area_struct *vma;
/*
* In some cases (e.g. Hyper-Threading), we want to avoid L1
* evictions by the processes running on the same package. One
* thing we can do is to shuffle the initial stack for them.
*/
p = arch_align_stack(p);
/*
* If this architecture has a platform capability string, copy it
* to userspace. In some cases (Sparc), this info is impossible
* for userspace to get any other way, in others (i386) it is
* merely difficult.
*/
u_platform = NULL;
if (k_platform) {
size_t len = strlen(k_platform) + 1;
u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
if (copy_to_user(u_platform, k_platform, len))
return -EFAULT;
}
/*
* If this architecture has a "base" platform capability
* string, copy it to userspace.
*/
u_base_platform = NULL;
if (k_base_platform) {
size_t len = strlen(k_base_platform) + 1;
u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
if (copy_to_user(u_base_platform, k_base_platform, len))
return -EFAULT;
}
/*
* Generate 16 random bytes for userspace PRNG seeding.
*/
get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
u_rand_bytes = (elf_addr_t __user *)
STACK_ALLOC(p, sizeof(k_rand_bytes));
if (copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
return -EFAULT;
/* Create the ELF interpreter info */
elf_info = (elf_addr_t *)mm->saved_auxv;
/* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
#define NEW_AUX_ENT(id, val) \
do { \
*elf_info++ = id; \
*elf_info++ = val; \
} while (0)
#ifdef ARCH_DLINFO
/*
* ARCH_DLINFO must come first so PPC can do its special alignment of
* AUXV.
* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
* ARCH_DLINFO changes
*/
ARCH_DLINFO;
#endif
NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
NEW_AUX_ENT(AT_PHDR, phdr_addr);
NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
NEW_AUX_ENT(AT_BASE, interp_load_addr);
NEW_AUX_ENT(AT_FLAGS, bprm_at_flags(bprm));
NEW_AUX_ENT(AT_ENTRY, e_entry);
NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid));
NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid));
NEW_AUX_ENT(AT_GID, from_kgid_munged(cred->user_ns, cred->gid));
NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid));
NEW_AUX_ENT(AT_SECURE, bprm->secureexec);
NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
#ifdef ELF_HWCAP2
NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
#endif
#ifdef ELF_HWCAP3
NEW_AUX_ENT(AT_HWCAP3, ELF_HWCAP3);
#endif
#ifdef ELF_HWCAP4
NEW_AUX_ENT(AT_HWCAP4, ELF_HWCAP4);
#endif
NEW_AUX_ENT(AT_EXECFN, bprm->exec);
if (k_platform) {
NEW_AUX_ENT(AT_PLATFORM,
(elf_addr_t)(unsigned long)u_platform);
}
if (k_base_platform) {
NEW_AUX_ENT(AT_BASE_PLATFORM,
(elf_addr_t)(unsigned long)u_base_platform);
}
if (bprm->have_execfd) {
NEW_AUX_ENT(AT_EXECFD, bprm->execfd);
}
#ifdef CONFIG_RSEQ
NEW_AUX_ENT(AT_RSEQ_FEATURE_SIZE, offsetof(struct rseq, end));
NEW_AUX_ENT(AT_RSEQ_ALIGN, rseq_alloc_align());
#endif
#undef NEW_AUX_ENT
/* AT_NULL is zero; clear the rest too */
memset(elf_info, 0, (char *)mm->saved_auxv +
sizeof(mm->saved_auxv) - (char *)elf_info);
/* And advance past the AT_NULL entry. */
elf_info += 2;
ei_index = elf_info - (elf_addr_t *)mm->saved_auxv;
sp = STACK_ADD(p, ei_index);
items = (argc + 1) + (envc + 1) + 1;
bprm->p = STACK_ROUND(sp, items);
/* Point sp at the lowest address on the stack */
#ifdef CONFIG_STACK_GROWSUP
sp = (elf_addr_t __user *)bprm->p - items - ei_index;
bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
#else
sp = (elf_addr_t __user *)bprm->p;
#endif
/*
* Grow the stack manually; some architectures have a limit on how
* far ahead a user-space access may be in order to grow the stack.
*/
if (mmap_write_lock_killable(mm))
return -EINTR;
vma = find_extend_vma_locked(mm, bprm->p);
mmap_write_unlock(mm);
if (!vma)
return -EFAULT;
/* Now, let's put argc (and argv, envp if appropriate) on the stack */
if (put_user(argc, sp++))
return -EFAULT;
/* Populate list of argv pointers back to argv strings. */
p = mm->arg_end = mm->arg_start;
while (argc-- > 0) {
size_t len;
if (put_user((elf_addr_t)p, sp++))
return -EFAULT;
len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(0, sp++))
return -EFAULT;
mm->arg_end = p;
/* Populate list of envp pointers back to envp strings. */
mm->env_end = mm->env_start = p;
while (envc-- > 0) {
size_t len;
if (put_user((elf_addr_t)p, sp++))
return -EFAULT;
len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(0, sp++))
return -EFAULT;
mm->env_end = p;
/* Put the elf_info on the stack in the right place. */
if (copy_to_user(sp, mm->saved_auxv, ei_index * sizeof(elf_addr_t)))
return -EFAULT;
return 0;
}
/*
* Map "eppnt->p_filesz" bytes from "filep" offset "eppnt->p_offset"
* into memory at "addr". (Note that p_filesz is rounded up to the
* next page, so any extra bytes from the file must be wiped.)
*/
static unsigned long elf_map(struct file *filep, unsigned long addr,
const struct elf_phdr *eppnt, int prot, int type,
unsigned long total_size)
{
unsigned long map_addr;
unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
addr = ELF_PAGESTART(addr);
size = ELF_PAGEALIGN(size);
/* mmap() will return -EINVAL if given a zero size, but a
* segment with zero filesize is perfectly valid */
if (!size)
return addr;
/*
* total_size is the size of the ELF (interpreter) image.
* The _first_ mmap needs to know the full size, otherwise
* randomization might put this image into an overlapping
* position with the ELF binary image. (since size < total_size)
* So we first map the 'big' image - and unmap the remainder at
* the end. (which unmap is needed for ELF images with holes.)
*/
if (total_size) {
total_size = ELF_PAGEALIGN(total_size);
map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
if (!BAD_ADDR(map_addr))
vm_munmap(map_addr+size, total_size-size);
} else
map_addr = vm_mmap(filep, addr, size, prot, type, off);
if ((type & MAP_FIXED_NOREPLACE) &&
PTR_ERR((void *)map_addr) == -EEXIST)
pr_info("%d (%s): Uhuuh, elf segment at %px requested but the memory is mapped already\n",
task_pid_nr(current), current->comm, (void *)addr);
return(map_addr);
}
/*
* Map "eppnt->p_filesz" bytes from "filep" offset "eppnt->p_offset"
* into memory at "addr". Memory from "p_filesz" through "p_memsz"
* rounded up to the next page is zeroed.
*/
static unsigned long elf_load(struct file *filep, unsigned long addr,
const struct elf_phdr *eppnt, int prot, int type,
unsigned long total_size)
{
unsigned long zero_start, zero_end;
unsigned long map_addr;
if (eppnt->p_filesz) {
map_addr = elf_map(filep, addr, eppnt, prot, type, total_size);
if (BAD_ADDR(map_addr))
return map_addr;
if (eppnt->p_memsz > eppnt->p_filesz) {
zero_start = map_addr + ELF_PAGEOFFSET(eppnt->p_vaddr) +
eppnt->p_filesz;
zero_end = map_addr + ELF_PAGEOFFSET(eppnt->p_vaddr) +
eppnt->p_memsz;
/*
* Zero the end of the last mapped page but ignore
* any errors if the segment isn't writable.
*/
if (padzero(zero_start) && (prot & PROT_WRITE))
return -EFAULT;
}
} else {
map_addr = zero_start = ELF_PAGESTART(addr);
zero_end = zero_start + ELF_PAGEOFFSET(eppnt->p_vaddr) +
eppnt->p_memsz;
}
if (eppnt->p_memsz > eppnt->p_filesz) {
/*
* Map the last of the segment.
* If the header is requesting these pages to be
* executable, honour that (ppc32 needs this).
*/
int error;
zero_start = ELF_PAGEALIGN(zero_start);
zero_end = ELF_PAGEALIGN(zero_end);
error = vm_brk_flags(zero_start, zero_end - zero_start,
prot & PROT_EXEC);
if (error)
map_addr = error;
}
return map_addr;
}
static unsigned long total_mapping_size(const struct elf_phdr *phdr, int nr)
{
elf_addr_t min_addr = -1;
elf_addr_t max_addr = 0;
bool pt_load = false;
int i;
for (i = 0; i < nr; i++) {
if (phdr[i].p_type == PT_LOAD) {
min_addr = min(min_addr, ELF_PAGESTART(phdr[i].p_vaddr));
max_addr = max(max_addr, phdr[i].p_vaddr + phdr[i].p_memsz);
pt_load = true;
}
}
return pt_load ? (max_addr - min_addr) : 0;
}
static int elf_read(struct file *file, void *buf, size_t len, loff_t pos)
{
ssize_t rv;
rv = kernel_read(file, buf, len, &pos);
if (unlikely(rv != len)) {
return (rv < 0) ? rv : -EIO;
}
return 0;
}
static unsigned long maximum_alignment(struct elf_phdr *cmds, int nr)
{
unsigned long alignment = 0;
int i;
for (i = 0; i < nr; i++) {
if (cmds[i].p_type == PT_LOAD) {
unsigned long p_align = cmds[i].p_align;
/* skip non-power of two alignments as invalid */
if (!is_power_of_2(p_align))
continue;
alignment = max(alignment, p_align);
}
}
/* ensure we align to at least one page */
return ELF_PAGEALIGN(alignment);
}
/**
* load_elf_phdrs() - load ELF program headers
* @elf_ex: ELF header of the binary whose program headers should be loaded
* @elf_file: the opened ELF binary file
*
* Loads ELF program headers from the binary file elf_file, which has the ELF
* header pointed to by elf_ex, into a newly allocated array. The caller is
* responsible for freeing the allocated data. Returns NULL upon failure.
*/
static struct elf_phdr *load_elf_phdrs(const struct elfhdr *elf_ex,
struct file *elf_file)
{
struct elf_phdr *elf_phdata = NULL;
int retval = -1;
unsigned int size;
/*
* If the size of this structure has changed, then punt, since
* we will be doing the wrong thing.
*/
if (elf_ex->e_phentsize != sizeof(struct elf_phdr))
goto out;
/* Sanity check the number of program headers... */
/* ...and their total size. */
size = sizeof(struct elf_phdr) * elf_ex->e_phnum;
if (size == 0 || size > 65536)
goto out;
elf_phdata = kmalloc(size, GFP_KERNEL);
if (!elf_phdata)
goto out;
/* Read in the program headers */
retval = elf_read(elf_file, elf_phdata, size, elf_ex->e_phoff);
out:
if (retval) {
kfree(elf_phdata);
elf_phdata = NULL;
}
return elf_phdata;
}
#ifndef CONFIG_ARCH_BINFMT_ELF_STATE
/**
* struct arch_elf_state - arch-specific ELF loading state
*
* This structure is used to preserve architecture specific data during
* the loading of an ELF file, throughout the checking of architecture
* specific ELF headers & through to the point where the ELF load is
* known to be proceeding (ie. SET_PERSONALITY).
*
* This implementation is a dummy for architectures which require no
* specific state.
*/
struct arch_elf_state {
};
#define INIT_ARCH_ELF_STATE {}
/**
* arch_elf_pt_proc() - check a PT_LOPROC..PT_HIPROC ELF program header
* @ehdr: The main ELF header
* @phdr: The program header to check
* @elf: The open ELF file
* @is_interp: True if the phdr is from the interpreter of the ELF being
* loaded, else false.
* @state: Architecture-specific state preserved throughout the process
* of loading the ELF.
*
* Inspects the program header phdr to validate its correctness and/or
* suitability for the system. Called once per ELF program header in the
* range PT_LOPROC to PT_HIPROC, for both the ELF being loaded and its
* interpreter.
*
* Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
* with that return code.
*/
static inline int arch_elf_pt_proc(struct elfhdr *ehdr,
struct elf_phdr *phdr,
struct file *elf, bool is_interp,
struct arch_elf_state *state)
{
/* Dummy implementation, always proceed */
return 0;
}
/**
* arch_check_elf() - check an ELF executable
* @ehdr: The main ELF header
* @has_interp: True if the ELF has an interpreter, else false.
* @interp_ehdr: The interpreter's ELF header
* @state: Architecture-specific state preserved throughout the process
* of loading the ELF.
*
* Provides a final opportunity for architecture code to reject the loading
* of the ELF & cause an exec syscall to return an error. This is called after
* all program headers to be checked by arch_elf_pt_proc have been.
*
* Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
* with that return code.
*/
static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp,
struct elfhdr *interp_ehdr,
struct arch_elf_state *state)
{
/* Dummy implementation, always proceed */
return 0;
}
#endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */
static inline int make_prot(u32 p_flags, struct arch_elf_state *arch_state,
bool has_interp, bool is_interp)
{
int prot = 0;
if (p_flags & PF_R)
prot |= PROT_READ;
if (p_flags & PF_W)
prot |= PROT_WRITE;
if (p_flags & PF_X)
prot |= PROT_EXEC;
return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp);
}
/* This is much more generalized than the library routine read function,
so we keep this separate. Technically the library read function
is only provided so that we can read a.out libraries that have
an ELF header */
static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
struct file *interpreter,
unsigned long no_base, struct elf_phdr *interp_elf_phdata,
struct arch_elf_state *arch_state)
{
struct elf_phdr *eppnt;
unsigned long load_addr = 0;
int load_addr_set = 0;
unsigned long error = ~0UL;
unsigned long total_size;
int i;
/* First of all, some simple consistency checks */
if (interp_elf_ex->e_type != ET_EXEC &&
interp_elf_ex->e_type != ET_DYN)
goto out;
if (!elf_check_arch(interp_elf_ex) ||
elf_check_fdpic(interp_elf_ex))
goto out;
if (!can_mmap_file(interpreter))
goto out;
total_size = total_mapping_size(interp_elf_phdata,
interp_elf_ex->e_phnum);
if (!total_size) {
error = -EINVAL;
goto out;
}
eppnt = interp_elf_phdata;
for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
if (eppnt->p_type == PT_LOAD) {
int elf_type = MAP_PRIVATE;
int elf_prot = make_prot(eppnt->p_flags, arch_state,
true, true);
unsigned long vaddr = 0;
unsigned long k, map_addr;
vaddr = eppnt->p_vaddr;
if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
elf_type |= MAP_FIXED;
else if (no_base && interp_elf_ex->e_type == ET_DYN)
load_addr = -vaddr;
map_addr = elf_load(interpreter, load_addr + vaddr,
eppnt, elf_prot, elf_type, total_size);
total_size = 0;
error = map_addr;
if (BAD_ADDR(map_addr))
goto out;
if (!load_addr_set &&
interp_elf_ex->e_type == ET_DYN) {
load_addr = map_addr - ELF_PAGESTART(vaddr);
load_addr_set = 1;
}
/*
* Check to see if the section's size will overflow the
* allowed task size. Note that p_filesz must always be
* <= p_memsize so it's only necessary to check p_memsz.
*/
k = load_addr + eppnt->p_vaddr;
if (BAD_ADDR(k) ||
eppnt->p_filesz > eppnt->p_memsz ||
eppnt->p_memsz > TASK_SIZE ||
TASK_SIZE - eppnt->p_memsz < k) {
error = -ENOMEM;
goto out;
}
}
}
error = load_addr;
out:
return error;
}
/*
* These are the functions used to load ELF style executables and shared
* libraries. There is no binary dependent code anywhere else.
*/
static int parse_elf_property(const char *data, size_t *off, size_t datasz,
struct arch_elf_state *arch,
bool have_prev_type, u32 *prev_type)
{
size_t o, step;
const struct gnu_property *pr;
int ret;
if (*off == datasz)
return -ENOENT;
if (WARN_ON_ONCE(*off > datasz || *off % ELF_GNU_PROPERTY_ALIGN))
return -EIO;
o = *off;
datasz -= *off;
if (datasz < sizeof(*pr))
return -ENOEXEC;
pr = (const struct gnu_property *)(data + o);
o += sizeof(*pr);
datasz -= sizeof(*pr);
if (pr->pr_datasz > datasz)
return -ENOEXEC;
WARN_ON_ONCE(o % ELF_GNU_PROPERTY_ALIGN);
step = round_up(pr->pr_datasz, ELF_GNU_PROPERTY_ALIGN);
if (step > datasz)
return -ENOEXEC;
/* Properties are supposed to be unique and sorted on pr_type: */
if (have_prev_type && pr->pr_type <= *prev_type)
return -ENOEXEC;
*prev_type = pr->pr_type;
ret = arch_parse_elf_property(pr->pr_type, data + o,
pr->pr_datasz, ELF_COMPAT, arch);
if (ret)
return ret;
*off = o + step;
return 0;
}
#define NOTE_DATA_SZ SZ_1K
#define NOTE_NAME_SZ (sizeof(NN_GNU_PROPERTY_TYPE_0))
static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
struct arch_elf_state *arch)
{
union {
struct elf_note nhdr;
char data[NOTE_DATA_SZ];
} note;
loff_t pos;
ssize_t n;
size_t off, datasz;
int ret;
bool have_prev_type;
u32 prev_type;
if (!IS_ENABLED(CONFIG_ARCH_USE_GNU_PROPERTY) || !phdr)
return 0;
/* load_elf_binary() shouldn't call us unless this is true... */
if (WARN_ON_ONCE(phdr->p_type != PT_GNU_PROPERTY))
return -ENOEXEC;
/* If the properties are crazy large, that's too bad (for now): */
if (phdr->p_filesz > sizeof(note))
return -ENOEXEC;
pos = phdr->p_offset;
n = kernel_read(f, &note, phdr->p_filesz, &pos);
BUILD_BUG_ON(sizeof(note) < sizeof(note.nhdr) + NOTE_NAME_SZ);
if (n < 0 || n < sizeof(note.nhdr) + NOTE_NAME_SZ)
return -EIO;
if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 ||
note.nhdr.n_namesz != NOTE_NAME_SZ ||
strncmp(note.data + sizeof(note.nhdr),
NN_GNU_PROPERTY_TYPE_0, n - sizeof(note.nhdr)))
return -ENOEXEC;
off = round_up(sizeof(note.nhdr) + NOTE_NAME_SZ,
ELF_GNU_PROPERTY_ALIGN);
if (off > n)
return -ENOEXEC;
if (note.nhdr.n_descsz > n - off)
return -ENOEXEC;
datasz = off + note.nhdr.n_descsz;
have_prev_type = false;
do {
ret = parse_elf_property(note.data, &off, datasz, arch,
have_prev_type, &prev_type);
have_prev_type = true;
} while (!ret);
return ret == -ENOENT ? 0 : ret;
}
static int load_elf_binary(struct linux_binprm *bprm)
{
struct file *interpreter = NULL; /* to shut gcc up */
unsigned long load_bias = 0, phdr_addr = 0;
int first_pt_load = 1;
unsigned long error;
struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
struct elf_phdr *elf_property_phdata = NULL;
unsigned long elf_brk;
bool brk_moved = false;
int retval, i;
unsigned long elf_entry;
unsigned long e_entry;
unsigned long interp_load_addr = 0;
unsigned long start_code, end_code, start_data, end_data;
unsigned long reloc_func_desc __maybe_unused = 0;
int executable_stack = EXSTACK_DEFAULT;
struct elfhdr *elf_ex = (struct elfhdr *)bprm->buf;
struct elfhdr *interp_elf_ex = NULL;
struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE;
struct mm_struct *mm;
struct pt_regs *regs;
retval = -ENOEXEC;
/* First of all, some simple consistency checks */
if (memcmp(elf_ex->e_ident, ELFMAG, SELFMAG) != 0)
goto out;
if (elf_ex->e_type != ET_EXEC && elf_ex->e_type != ET_DYN)
goto out;
if (!elf_check_arch(elf_ex))
goto out;
if (elf_check_fdpic(elf_ex))
goto out;
if (!can_mmap_file(bprm->file))
goto out;
elf_phdata = load_elf_phdrs(elf_ex, bprm->file);
if (!elf_phdata)
goto out;
elf_ppnt = elf_phdata;
for (i = 0; i < elf_ex->e_phnum; i++, elf_ppnt++) {
char *elf_interpreter;
if (elf_ppnt->p_type == PT_GNU_PROPERTY) {
elf_property_phdata = elf_ppnt;
continue;
}
if (elf_ppnt->p_type != PT_INTERP)
continue;
/*
* This is the program interpreter used for shared libraries -
* for now assume that this is an a.out format binary.
*/
retval = -ENOEXEC;
if (elf_ppnt->p_filesz > PATH_MAX || elf_ppnt->p_filesz < 2)
goto out_free_ph;
retval = -ENOMEM;
elf_interpreter = kmalloc(elf_ppnt->p_filesz, GFP_KERNEL);
if (!elf_interpreter)
goto out_free_ph;
retval = elf_read(bprm->file, elf_interpreter, elf_ppnt->p_filesz,
elf_ppnt->p_offset);
if (retval < 0)
goto out_free_interp;
/* make sure path is NULL terminated */
retval = -ENOEXEC;
if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
goto out_free_interp;
interpreter = bprm_open_interpreter(bprm, elf_interpreter);
kfree(elf_interpreter);
retval = PTR_ERR(interpreter);
if (IS_ERR(interpreter))
goto out_free_ph;
/*
* If the binary is not readable then enforce mm->dumpable = 0
* regardless of the interpreter's permissions.
*/
would_dump(bprm, interpreter);
interp_elf_ex = kmalloc_obj(*interp_elf_ex);
if (!interp_elf_ex) {
retval = -ENOMEM;
goto out_free_file;
}
/* Get the exec headers */
retval = elf_read(interpreter, interp_elf_ex,
sizeof(*interp_elf_ex), 0);
if (retval < 0)
goto out_free_dentry;
break;
out_free_interp:
kfree(elf_interpreter);
goto out_free_ph;
}
/* No PT_INTERP to substitute for: the override does not apply. */
bprm_drop_loader(bprm);
elf_ppnt = elf_phdata;
for (i = 0; i < elf_ex->e_phnum; i++, elf_ppnt++)
switch (elf_ppnt->p_type) {
case PT_GNU_STACK:
if (elf_ppnt->p_flags & PF_X)
executable_stack = EXSTACK_ENABLE_X;
else
executable_stack = EXSTACK_DISABLE_X;
break;
case PT_LOPROC ... PT_HIPROC:
retval = arch_elf_pt_proc(elf_ex, elf_ppnt,
bprm->file, false,
&arch_state);
if (retval)
goto out_free_dentry;
break;
}
/* Some simple consistency checks for the interpreter */
if (interpreter) {
retval = -ELIBBAD;
/* Not an ELF interpreter */
if (memcmp(interp_elf_ex->e_ident, ELFMAG, SELFMAG) != 0)
goto out_free_dentry;
/* Verify the interpreter has a valid arch */
if (!elf_check_arch(interp_elf_ex) ||
elf_check_fdpic(interp_elf_ex))
goto out_free_dentry;
/* Load the interpreter program headers */
interp_elf_phdata = load_elf_phdrs(interp_elf_ex,
interpreter);
if (!interp_elf_phdata)
goto out_free_dentry;
/* Pass PT_LOPROC..PT_HIPROC headers to arch code */
elf_property_phdata = NULL;
elf_ppnt = interp_elf_phdata;
for (i = 0; i < interp_elf_ex->e_phnum; i++, elf_ppnt++)
switch (elf_ppnt->p_type) {
case PT_GNU_PROPERTY:
elf_property_phdata = elf_ppnt;
break;
case PT_LOPROC ... PT_HIPROC:
retval = arch_elf_pt_proc(interp_elf_ex,
elf_ppnt, interpreter,
true, &arch_state);
if (retval)
goto out_free_dentry;
break;
}
}
retval = parse_elf_properties(interpreter ?: bprm->file,
elf_property_phdata, &arch_state);
if (retval)
goto out_free_dentry;
/*
* Allow arch code to reject the ELF at this point, whilst it's
* still possible to return an error to the code that invoked
* the exec syscall.
*/
retval = arch_check_elf(elf_ex,
!!interpreter, interp_elf_ex,
&arch_state);
if (retval)
goto out_free_dentry;
/* Flush all traces of the currently running executable */
retval = begin_new_exec(bprm);
if (retval)
goto out_free_dentry;
/* Do this immediately, since STACK_TOP as used in setup_arg_pages
may depend on the personality. */
SET_PERSONALITY2(*elf_ex, &arch_state);
if (elf_read_implies_exec(*elf_ex, executable_stack))
current->personality |= READ_IMPLIES_EXEC;
const int snapshot_randomize_va_space = READ_ONCE(randomize_va_space);
if (!(current->personality & ADDR_NO_RANDOMIZE) && snapshot_randomize_va_space)
current->flags |= PF_RANDOMIZE;
setup_new_exec(bprm);
/* Do this so that we can load the interpreter, if need be. We will
change some of these later */
retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
executable_stack);
if (retval < 0)
goto out_free_dentry;
elf_brk = 0;
start_code = ~0UL;
end_code = 0;
start_data = 0;
end_data = 0;
/* Now we do a little grungy work by mmapping the ELF image into
the correct location in memory. */
for(i = 0, elf_ppnt = elf_phdata;
i < elf_ex->e_phnum; i++, elf_ppnt++) {
int elf_prot, elf_flags;
unsigned long k, vaddr;
unsigned long total_size = 0;
unsigned long alignment;
if (elf_ppnt->p_type != PT_LOAD)
continue;
elf_prot = make_prot(elf_ppnt->p_flags, &arch_state,
!!interpreter, false);
elf_flags = MAP_PRIVATE;
vaddr = elf_ppnt->p_vaddr;
/*
* The first time through the loop, first_pt_load is true:
* layout will be calculated. Once set, use MAP_FIXED since
* we know we've already safely mapped the entire region with
* MAP_FIXED_NOREPLACE in the once-per-binary logic following.
*/
if (!first_pt_load) {
elf_flags |= MAP_FIXED;
} else if (elf_ex->e_type == ET_EXEC) {
/*
* This logic is run once for the first LOAD Program
* Header for ET_EXEC binaries. No special handling
* is needed.
*/
elf_flags |= MAP_FIXED_NOREPLACE;
} else if (elf_ex->e_type == ET_DYN) {
/*
* This logic is run once for the first LOAD Program
* Header for ET_DYN binaries to calculate the
* randomization (load_bias) for all the LOAD
* Program Headers.
*/
/*
* Calculate the entire size of the ELF mapping
* (total_size), used for the initial mapping,
* due to load_addr_set which is set to true later
* once the initial mapping is performed.
*
* Note that this is only sensible when the LOAD
* segments are contiguous (or overlapping). If
* used for LOADs that are far apart, this would
* cause the holes between LOADs to be mapped,
* running the risk of having the mapping fail,
* as it would be larger than the ELF file itself.
*
* As a result, only ET_DYN does this, since
* some ET_EXEC (e.g. ia64) may have large virtual
* memory holes between LOADs.
*
*/
total_size = total_mapping_size(elf_phdata,
elf_ex->e_phnum);
if (!total_size) {
retval = -EINVAL;
goto out_free_dentry;
}
/* Calculate any requested alignment. */
alignment = maximum_alignment(elf_phdata, elf_ex->e_phnum);
/**
* DOC: PIE handling
*
* There are effectively two types of ET_DYN ELF
* binaries: programs (i.e. PIE: ET_DYN with
* PT_INTERP) and loaders (i.e. static PIE: ET_DYN
* without PT_INTERP, usually the ELF interpreter
* itself). Loaders must be loaded away from programs
* since the program may otherwise collide with the
* loader (especially for ET_EXEC which does not have
* a randomized position).
*
* For example, to handle invocations of
* "./ld.so someprog" to test out a new version of
* the loader, the subsequent program that the
* loader loads must avoid the loader itself, so
* they cannot share the same load range. Sufficient
* room for the brk must be allocated with the
* loader as well, since brk must be available with
* the loader.
*
* Therefore, programs are loaded offset from
* ELF_ET_DYN_BASE and loaders are loaded into the
* independently randomized mmap region (0 load_bias
* without MAP_FIXED nor MAP_FIXED_NOREPLACE).
*
* See below for "brk" handling details, which is
* also affected by program vs loader and ASLR.
*/
if (interpreter) {
/* On ET_DYN with PT_INTERP, we do the ASLR. */
load_bias = ELF_ET_DYN_BASE;
if (current->flags & PF_RANDOMIZE)
load_bias += arch_mmap_rnd();
/* Adjust alignment as requested. */
if (alignment)
load_bias &= ~(alignment - 1);
elf_flags |= MAP_FIXED_NOREPLACE;
} else {
/*
* For ET_DYN without PT_INTERP, we rely on
* the architectures's (potentially ASLR) mmap
* base address (via a load_bias of 0).
*
* When a large alignment is requested, we
* must do the allocation at address "0" right
* now to discover where things will load so
* that we can adjust the resulting alignment.
* In this case (load_bias != 0), we can use
* MAP_FIXED_NOREPLACE to make sure the mapping
* doesn't collide with anything.
*/
if (alignment > ELF_MIN_ALIGN) {
load_bias = elf_load(bprm->file, 0, elf_ppnt,
elf_prot, elf_flags, total_size);
if (BAD_ADDR(load_bias)) {
retval = IS_ERR_VALUE(load_bias) ?
PTR_ERR((void*)load_bias) : -EINVAL;
goto out_free_dentry;
}
vm_munmap(load_bias, total_size);
/* Adjust alignment as requested. */
if (alignment)
load_bias &= ~(alignment - 1);
elf_flags |= MAP_FIXED_NOREPLACE;
} else
load_bias = 0;
}
/*
* Since load_bias is used for all subsequent loading
* calculations, we must lower it by the first vaddr
* so that the remaining calculations based on the
* ELF vaddrs will be correctly offset. The result
* is then page aligned.
*/
load_bias = ELF_PAGESTART(load_bias - vaddr);
}
error = elf_load(bprm->file, load_bias + vaddr, elf_ppnt,
elf_prot, elf_flags, total_size);
if (BAD_ADDR(error)) {
retval = IS_ERR_VALUE(error) ?
PTR_ERR((void*)error) : -EINVAL;
goto out_free_dentry;
}
if (first_pt_load) {
first_pt_load = 0;
if (elf_ex->e_type == ET_DYN) {
load_bias += error -
ELF_PAGESTART(load_bias + vaddr);
reloc_func_desc = load_bias;
}
}
/*
* Figure out which segment in the file contains the Program
* Header table, and map to the associated memory address.
*/
if (elf_ppnt->p_offset <= elf_ex->e_phoff &&
elf_ex->e_phoff < elf_ppnt->p_offset + elf_ppnt->p_filesz) {
phdr_addr = elf_ex->e_phoff - elf_ppnt->p_offset +
elf_ppnt->p_vaddr;
}
k = elf_ppnt->p_vaddr;
if ((elf_ppnt->p_flags & PF_X) && k < start_code)
start_code = k;
if (start_data < k)
start_data = k;
/*
* Check to see if the section's size will overflow the
* allowed task size. Note that p_filesz must always be
* <= p_memsz so it is only necessary to check p_memsz.
*/
if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
elf_ppnt->p_memsz > TASK_SIZE ||
TASK_SIZE - elf_ppnt->p_memsz < k) {
/* set_brk can never work. Avoid overflows. */
retval = -EINVAL;
goto out_free_dentry;
}
k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
if ((elf_ppnt->p_flags & PF_X) && end_code < k)
end_code = k;
if (end_data < k)
end_data = k;
k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
if (k > elf_brk)
elf_brk = k;
}
e_entry = elf_ex->e_entry + load_bias;
phdr_addr += load_bias;
elf_brk += load_bias;
start_code += load_bias;
end_code += load_bias;
start_data += load_bias;
end_data += load_bias;
if (interpreter) {
elf_entry = load_elf_interp(interp_elf_ex,
interpreter,
load_bias, interp_elf_phdata,
&arch_state);
if (!IS_ERR_VALUE(elf_entry)) {
/*
* load_elf_interp() returns relocation
* adjustment
*/
interp_load_addr = elf_entry;
elf_entry += interp_elf_ex->e_entry;
}
if (BAD_ADDR(elf_entry)) {
retval = IS_ERR_VALUE(elf_entry) ?
(int)elf_entry : -EINVAL;
goto out_free_dentry;
}
reloc_func_desc = interp_load_addr;
exe_file_allow_write_access(interpreter);
fput(interpreter);
kfree(interp_elf_ex);
kfree(interp_elf_phdata);
} else {
elf_entry = e_entry;
if (BAD_ADDR(elf_entry)) {
retval = -EINVAL;
goto out_free_dentry;
}
}
kfree(elf_phdata);
set_binfmt(&elf_format);
#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
retval = ARCH_SETUP_ADDITIONAL_PAGES(bprm, elf_ex, !!interpreter);
if (retval < 0)
goto out;
#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
retval = create_elf_tables(bprm, elf_ex, interp_load_addr,
e_entry, phdr_addr);
if (retval < 0)
goto out;
mm = current->mm;
mm->end_code = end_code;
mm->start_code = start_code;
mm->start_data = start_data;
mm->end_data = end_data;
mm->start_stack = bprm->p;
elf_coredump_set_mm_eflags(mm, elf_ex->e_flags);
/**
* DOC: "brk" handling
*
* For architectures with ELF randomization, when executing a
* loader directly (i.e. static PIE: ET_DYN without PT_INTERP),
* move the brk area out of the mmap region and into the unused
* ELF_ET_DYN_BASE region. Since "brk" grows up it may collide
* early with the stack growing down or other regions being put
* into the mmap region by the kernel (e.g. vdso).
*
* In the CONFIG_COMPAT_BRK case, though, everything is turned
* off because we're not allowed to move the brk at all.
*/
if (!IS_ENABLED(CONFIG_COMPAT_BRK) &&
IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) &&
elf_ex->e_type == ET_DYN && !interpreter) {
elf_brk = ELF_ET_DYN_BASE;
/* This counts as moving the brk, so let brk(2) know. */
brk_moved = true;
}
mm->start_brk = mm->brk = ELF_PAGEALIGN(elf_brk);
if ((current->flags & PF_RANDOMIZE) && snapshot_randomize_va_space > 1) {
/*
* If we didn't move the brk to ELF_ET_DYN_BASE (above),
* leave a gap between .bss and brk.
*/
if (!brk_moved)
mm->brk = mm->start_brk = mm->brk + PAGE_SIZE;
mm->brk = mm->start_brk = arch_randomize_brk(mm);
brk_moved = true;
}
#ifdef compat_brk_randomized
if (brk_moved)
current->brk_randomized = 1;
#endif
if (current->personality & MMAP_PAGE_ZERO) {
/* Why this, you ask??? Well SVr4 maps page 0 as read-only,
and some applications "depend" upon this behavior.
Since we do not have the power to recompile these, we
emulate the SVr4 behavior. Sigh. */
error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
MAP_FIXED | MAP_PRIVATE, 0);
if (!error)
mseal_mmap_page_zero();
}
regs = current_pt_regs();
#ifdef ELF_PLAT_INIT
/*
* The ABI may specify that certain registers be set up in special
* ways (on i386 %edx is the address of a DT_FINI function, for
* example. In addition, it may also specify (eg, PowerPC64 ELF)
* that the e_entry field is the address of the function descriptor
* for the startup routine, rather than the address of the startup
* routine itself. This macro performs whatever initialization to
* the regs structure is required as well as any relocations to the
* function descriptor entries when executing dynamically links apps.
*/
ELF_PLAT_INIT(regs, reloc_func_desc);
#endif
finalize_exec(bprm);
START_THREAD(elf_ex, regs, elf_entry, bprm->p);
retval = 0;
out:
return retval;
/* error cleanup */
out_free_dentry:
kfree(interp_elf_ex);
kfree(interp_elf_phdata);
out_free_file:
exe_file_allow_write_access(interpreter);
if (interpreter)
fput(interpreter);
out_free_ph:
kfree(elf_phdata);
goto out;
}
#ifdef CONFIG_ELF_CORE
/*
* ELF core dumper
*
* Modelled on fs/exec.c:aout_core_dump()
* Jeremy Fitzhardinge <jeremy@sw.oz.au>
*/
/* An ELF note in memory */
struct memelfnote
{
const char *name;
int type;
unsigned int datasz;
void *data;
};
static int notesize(struct memelfnote *en)
{
int sz;
sz = sizeof(struct elf_note);
sz += roundup(strlen(en->name) + 1, 4);
sz += roundup(en->datasz, 4);
return sz;
}
static int writenote(struct memelfnote *men, struct coredump_params *cprm)
{
struct elf_note en;
en.n_namesz = strlen(men->name) + 1;
en.n_descsz = men->datasz;
en.n_type = men->type;
return dump_emit(cprm, &en, sizeof(en)) &&
dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
}
static void fill_elf_header(struct elfhdr *elf, int segs,
u16 machine, u32 flags)
{
memset(elf, 0, sizeof(*elf));
memcpy(elf->e_ident, ELFMAG, SELFMAG);
elf->e_ident[EI_CLASS] = ELF_CLASS;
elf->e_ident[EI_DATA] = ELF_DATA;
elf->e_ident[EI_VERSION] = EV_CURRENT;
elf->e_ident[EI_OSABI] = ELF_OSABI;
elf->e_type = ET_CORE;
elf->e_machine = machine;
elf->e_version = EV_CURRENT;
elf->e_phoff = sizeof(struct elfhdr);
elf->e_flags = flags;
elf->e_ehsize = sizeof(struct elfhdr);
elf->e_phentsize = sizeof(struct elf_phdr);
elf->e_phnum = segs;
}
static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
{
phdr->p_type = PT_NOTE;
phdr->p_offset = offset;
phdr->p_vaddr = 0;
phdr->p_paddr = 0;
phdr->p_filesz = sz;
phdr->p_memsz = 0;
phdr->p_flags = 0;
phdr->p_align = 4;
}
static void __fill_note(struct memelfnote *note, const char *name, int type,
unsigned int sz, void *data)
{
note->name = name;
note->type = type;
note->datasz = sz;
note->data = data;
}
#define fill_note(note, type, sz, data) \
__fill_note(note, NN_ ## type, NT_ ## type, sz, data)
/*
* fill up all the fields in prstatus from the given task struct, except
* registers which need to be filled up separately.
*/
static void fill_prstatus(struct elf_prstatus_common *prstatus,
struct task_struct *p, long signr)
{
prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
prstatus->pr_sigpend = p->pending.signal.sig[0];
prstatus->pr_sighold = p->blocked.sig[0];
rcu_read_lock();
prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
rcu_read_unlock();
prstatus->pr_pid = task_pid_vnr(p);
prstatus->pr_pgrp = task_pgrp_vnr(p);
prstatus->pr_sid = task_session_vnr(p);
if (thread_group_leader(p)) {
struct task_cputime cputime;
/*
* This is the record for the group leader. It shows the
* group-wide total, not its individual thread total.
*/
thread_group_cputime(p, &cputime);
prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
} else {
u64 utime, stime;
task_cputime(p, &utime, &stime);
prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
}
prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
}
static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
struct mm_struct *mm)
{
const struct cred *cred;
unsigned int i, len;
unsigned int state;
/* first copy the parameters from user space */
memset(psinfo, 0, sizeof(struct elf_prpsinfo));
len = mm->arg_end - mm->arg_start;
if (len >= ELF_PRARGSZ)
len = ELF_PRARGSZ-1;
if (copy_from_user(&psinfo->pr_psargs,
(const char __user *)mm->arg_start, len))
return -EFAULT;
for(i = 0; i < len; i++)
if (psinfo->pr_psargs[i] == 0)
psinfo->pr_psargs[i] = ' ';
psinfo->pr_psargs[len] = 0;
rcu_read_lock();
psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
rcu_read_unlock();
psinfo->pr_pid = task_pid_vnr(p);
psinfo->pr_pgrp = task_pgrp_vnr(p);
psinfo->pr_sid = task_session_vnr(p);
state = READ_ONCE(p->__state);
i = state ? ffz(~state) + 1 : 0;
psinfo->pr_state = i;
psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
psinfo->pr_zomb = psinfo->pr_sname == 'Z';
psinfo->pr_nice = task_nice(p);
psinfo->pr_flag = p->flags;
rcu_read_lock();
cred = __task_cred(p);
SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
rcu_read_unlock();
get_task_comm(psinfo->pr_fname, p);
return 0;
}
static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
{
elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
int i = 0;
do
i += 2;
while (auxv[i - 2] != AT_NULL);
fill_note(note, AUXV, i * sizeof(elf_addr_t), auxv);
}
static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
const kernel_siginfo_t *siginfo)
{
copy_siginfo_to_external(csigdata, siginfo);
fill_note(note, SIGINFO, sizeof(*csigdata), csigdata);
}
/*
* Format of NT_FILE note:
*
* long count -- how many files are mapped
* long page_size -- units for file_ofs
* array of [COUNT] elements of
* long start
* long end
* long file_ofs
* followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL...
*/
static int fill_files_note(struct memelfnote *note, struct coredump_params *cprm)
{
unsigned count, size, names_ofs, remaining, n;
user_long_t *data;
user_long_t *start_end_ofs;
char *name_base, *name_curpos;
int i;
/* *Estimated* file count and total data size needed */
count = cprm->vma_count;
if (count > UINT_MAX / 64)
return -EINVAL;
size = count * 64;
names_ofs = (2 + 3 * count) * sizeof(data[0]);
alloc:
/* paranoia check */
if (size >= core_file_note_size_limit) {
pr_warn_once("coredump Note size too large: %u (does kernel.core_file_note_size_limit sysctl need adjustment?\n",
size);
return -EINVAL;
}
size = round_up(size, PAGE_SIZE);
/*
* "size" can be 0 here legitimately.
* Let it ENOMEM and omit NT_FILE section which will be empty anyway.
*/
data = kvmalloc(size, GFP_KERNEL);
if (ZERO_OR_NULL_PTR(data))
return -ENOMEM;
start_end_ofs = data + 2;
name_base = name_curpos = ((char *)data) + names_ofs;
remaining = size - names_ofs;
count = 0;
for (i = 0; i < cprm->vma_count; i++) {
struct core_vma_metadata *m = &cprm->vma_meta[i];
struct file *file;
const char *filename;
file = m->file;
if (!file)
continue;
filename = file_path(file, name_curpos, remaining);
if (IS_ERR(filename)) {
if (PTR_ERR(filename) == -ENAMETOOLONG) {
kvfree(data);
size = size * 5 / 4;
goto alloc;
}
continue;
}
/* file_path() fills at the end, move name down */
/* n = strlen(filename) + 1: */
n = (name_curpos + remaining) - filename;
remaining = filename - name_curpos;
memmove(name_curpos, filename, n);
name_curpos += n;
*start_end_ofs++ = m->start;
*start_end_ofs++ = m->end;
*start_end_ofs++ = m->pgoff;
count++;
}
/* Now we know exact count of files, can store it */
data[0] = count;
data[1] = PAGE_SIZE;
/*
* Count usually is less than mm->map_count,
* we need to move filenames down.
*/
n = cprm->vma_count - count;
if (n != 0) {
unsigned shift_bytes = n * 3 * sizeof(data[0]);
memmove(name_base - shift_bytes, name_base,
name_curpos - name_base);
name_curpos -= shift_bytes;
}
size = name_curpos - (char *)data;
fill_note(note, FILE, size, data);
return 0;
}
#include <linux/regset.h>
struct elf_thread_core_info {
struct elf_thread_core_info *next;
struct task_struct *task;
struct elf_prstatus prstatus;
struct memelfnote notes[];
};
struct elf_note_info {
struct elf_thread_core_info *thread;
struct memelfnote psinfo;
struct memelfnote signote;
struct memelfnote auxv;
struct memelfnote files;
user_siginfo_t csigdata;
size_t size;
int thread_notes;
};
#ifdef CORE_DUMP_USE_REGSET
/*
* When a regset has a writeback hook, we call it on each thread before
* dumping user memory. On register window machines, this makes sure the
* user memory backing the register data is up to date before we read it.
*/
static void do_thread_regset_writeback(struct task_struct *task,
const struct user_regset *regset)
{
if (regset->writeback)
regset->writeback(task, regset, 1);
}
#ifndef PRSTATUS_SIZE
#define PRSTATUS_SIZE sizeof(struct elf_prstatus)
#endif
#ifndef SET_PR_FPVALID
#define SET_PR_FPVALID(S) ((S)->pr_fpvalid = 1)
#endif
static int fill_thread_core_info(struct elf_thread_core_info *t,
const struct user_regset_view *view,
long signr, struct elf_note_info *info)
{
unsigned int note_iter, view_iter;
/*
* NT_PRSTATUS is the one special case, because the regset data
* goes into the pr_reg field inside the note contents, rather
* than being the whole note contents. We fill the regset in here.
* We assume that regset 0 is NT_PRSTATUS.
*/
fill_prstatus(&t->prstatus.common, t->task, signr);
regset_get(t->task, &view->regsets[0],
sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
fill_note(&t->notes[0], PRSTATUS, PRSTATUS_SIZE, &t->prstatus);
info->size += notesize(&t->notes[0]);
do_thread_regset_writeback(t->task, &view->regsets[0]);
/*
* Each other regset might generate a note too. For each regset
* that has no core_note_type or is inactive, skip it.
*/
note_iter = 1;
for (view_iter = 1; view_iter < view->n; ++view_iter) {
const struct user_regset *regset = &view->regsets[view_iter];
int note_type = regset->core_note_type;
const char *note_name = regset->core_note_name;
bool is_fpreg = note_type == NT_PRFPREG;
void *data;
int ret;
do_thread_regset_writeback(t->task, regset);
if (!note_type) // not for coredumps
continue;
if (regset->active && regset->active(t->task, regset) <= 0)
continue;
ret = regset_get_alloc(t->task, regset, ~0U, &data);
if (ret < 0)
continue;
if (WARN_ON_ONCE(note_iter >= info->thread_notes))
break;
if (is_fpreg)
SET_PR_FPVALID(&t->prstatus);
/* There should be a note name, but if not, guess: */
if (WARN_ON_ONCE(!note_name))
note_name = "LINUX";
else
/* Warn on non-legacy-compatible names, for now. */
WARN_ON_ONCE(strcmp(note_name,
is_fpreg ? "CORE" : "LINUX"));
__fill_note(&t->notes[note_iter], note_name, note_type,
ret, data);
info->size += notesize(&t->notes[note_iter]);
note_iter++;
}
return 1;
}
#else
static int fill_thread_core_info(struct elf_thread_core_info *t,
const struct user_regset_view *view,
long signr, struct elf_note_info *info)
{
struct task_struct *p = t->task;
elf_fpregset_t *fpu;
fill_prstatus(&t->prstatus.common, p, signr);
elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
fill_note(&t->notes[0], PRSTATUS, sizeof(t->prstatus), &t->prstatus);
info->size += notesize(&t->notes[0]);
fpu = kzalloc_obj(elf_fpregset_t);
if (!fpu || !elf_core_copy_task_fpregs(p, fpu)) {
kfree(fpu);
return 1;
}
t->prstatus.pr_fpvalid = 1;
fill_note(&t->notes[1], PRFPREG, sizeof(*fpu), fpu);
info->size += notesize(&t->notes[1]);
return 1;
}
#endif
static int fill_note_info(struct elfhdr *elf, int phdrs,
struct elf_note_info *info,
struct coredump_params *cprm)
{
struct task_struct *dump_task = current;
const struct user_regset_view *view;
struct elf_thread_core_info *t;
struct elf_prpsinfo *psinfo;
struct core_thread *ct;
u16 machine;
u32 flags;
psinfo = kmalloc_obj(*psinfo);
if (!psinfo)
return 0;
fill_note(&info->psinfo, PRPSINFO, sizeof(*psinfo), psinfo);
#ifdef CORE_DUMP_USE_REGSET
view = task_user_regset_view(dump_task);
/*
* Figure out how many notes we're going to need for each thread.
*/
info->thread_notes = 0;
for (int i = 0; i < view->n; ++i)
if (view->regsets[i].core_note_type != 0)
++info->thread_notes;
/*
* Sanity check. We rely on regset 0 being in NT_PRSTATUS,
* since it is our one special case.
*/
if (unlikely(info->thread_notes == 0) ||
unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
WARN_ON(1);
return 0;
}
machine = view->e_machine;
flags = view->e_flags;
#else
view = NULL;
info->thread_notes = 2;
machine = ELF_ARCH;
flags = ELF_CORE_EFLAGS;
#endif
/*
* Override ELF e_flags with value taken from process,
* if arch needs that.
*/
flags = elf_coredump_get_mm_eflags(dump_task->mm, flags);
/*
* Initialize the ELF file header.
*/
fill_elf_header(elf, phdrs, machine, flags);
/*
* Allocate a structure for each thread.
*/
info->thread = kzalloc_flex(*info->thread, notes, info->thread_notes);
if (unlikely(!info->thread))
return 0;
info->thread->task = dump_task;
for (ct = dump_task->signal->core_state->dumper.next; ct; ct = ct->next) {
t = kzalloc_flex(*t, notes, info->thread_notes);
if (unlikely(!t))
return 0;
t->task = ct->task;
t->next = info->thread->next;
info->thread->next = t;
}
/*
* Now fill in each thread's information.
*/
for (t = info->thread; t != NULL; t = t->next)
if (!fill_thread_core_info(t, view, cprm->siginfo->si_signo, info))
return 0;
/*
* Fill in the two process-wide notes.
*/
fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
info->size += notesize(&info->psinfo);
fill_siginfo_note(&info->signote, &info->csigdata, cprm->siginfo);
info->size += notesize(&info->signote);
fill_auxv_note(&info->auxv, current->mm);
info->size += notesize(&info->auxv);
if (fill_files_note(&info->files, cprm) == 0)
info->size += notesize(&info->files);
return 1;
}
/*
* Write all the notes for each thread. When writing the first thread, the
* process-wide notes are interleaved after the first thread-specific note.
*/
static int write_note_info(struct elf_note_info *info,
struct coredump_params *cprm)
{
bool first = true;
struct elf_thread_core_info *t = info->thread;
do {
int i;
if (!writenote(&t->notes[0], cprm))
return 0;
if (first && !writenote(&info->psinfo, cprm))
return 0;
if (first && !writenote(&info->signote, cprm))
return 0;
if (first && !writenote(&info->auxv, cprm))
return 0;
if (first && info->files.data &&
!writenote(&info->files, cprm))
return 0;
for (i = 1; i < info->thread_notes; ++i)
if (t->notes[i].data &&
!writenote(&t->notes[i], cprm))
return 0;
first = false;
t = t->next;
} while (t);
return 1;
}
static void free_note_info(struct elf_note_info *info)
{
struct elf_thread_core_info *threads = info->thread;
while (threads) {
unsigned int i;
struct elf_thread_core_info *t = threads;
threads = t->next;
WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
for (i = 1; i < info->thread_notes; ++i)
kvfree(t->notes[i].data);
kfree(t);
}
kfree(info->psinfo.data);
kvfree(info->files.data);
}
static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
elf_addr_t e_shoff, int segs)
{
elf->e_shoff = e_shoff;
elf->e_shentsize = sizeof(*shdr4extnum);
elf->e_shnum = 1;
elf->e_shstrndx = SHN_UNDEF;
memset(shdr4extnum, 0, sizeof(*shdr4extnum));
shdr4extnum->sh_type = SHT_NULL;
shdr4extnum->sh_size = elf->e_shnum;
shdr4extnum->sh_link = elf->e_shstrndx;
shdr4extnum->sh_info = segs;
}
/*
* Actual dumper
*
* This is a two-pass process; first we find the offsets of the bits,
* and then they are actually written out. If we run out of core limit
* we just truncate.
*/
static int elf_core_dump(struct coredump_params *cprm)
{
int has_dumped = 0;
int segs, i;
struct elfhdr elf;
loff_t offset = 0, dataoff;
struct elf_note_info info = { };
struct elf_phdr *phdr4note = NULL;
struct elf_shdr *shdr4extnum = NULL;
Elf_Half e_phnum;
elf_addr_t e_shoff;
/*
* The number of segs are recored into ELF header as 16bit value.
* Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
*/
segs = cprm->vma_count + elf_core_extra_phdrs(cprm);
/* for notes section */
segs++;
/* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
* this, kernel supports extended numbering. Have a look at
* include/linux/elf.h for further information. */
e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
/*
* Collect all the non-memory information about the process for the
* notes. This also sets up the file header.
*/
if (!fill_note_info(&elf, e_phnum, &info, cprm))
goto end_coredump;
has_dumped = 1;
offset += sizeof(elf); /* ELF header */
offset += segs * sizeof(struct elf_phdr); /* Program headers */
/* Write notes phdr entry */
{
size_t sz = info.size;
/* For cell spufs and x86 xstate */
sz += elf_coredump_extra_notes_size();
phdr4note = kmalloc_obj(*phdr4note);
if (!phdr4note)
goto end_coredump;
fill_elf_note_phdr(phdr4note, sz, offset);
offset += sz;
}
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
offset += cprm->vma_data_size;
offset += elf_core_extra_data_size(cprm);
e_shoff = offset;
if (e_phnum == PN_XNUM) {
shdr4extnum = kmalloc_obj(*shdr4extnum);
if (!shdr4extnum)
goto end_coredump;
fill_extnum_info(&elf, shdr4extnum, e_shoff, segs);
}
offset = dataoff;
if (!dump_emit(cprm, &elf, sizeof(elf)))
goto end_coredump;
if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
goto end_coredump;
/* Write program headers for segments dump */
for (i = 0; i < cprm->vma_count; i++) {
struct core_vma_metadata *meta = cprm->vma_meta + i;
struct elf_phdr phdr;
phdr.p_type = PT_LOAD;
phdr.p_offset = offset;
phdr.p_vaddr = meta->start;
phdr.p_paddr = 0;
phdr.p_filesz = meta->dump_size;
phdr.p_memsz = meta->end - meta->start;
offset += phdr.p_filesz;
phdr.p_flags = 0;
if (meta->flags & VM_READ)
phdr.p_flags |= PF_R;
if (meta->flags & VM_WRITE)
phdr.p_flags |= PF_W;
if (meta->flags & VM_EXEC)
phdr.p_flags |= PF_X;
phdr.p_align = ELF_EXEC_PAGESIZE;
if (!dump_emit(cprm, &phdr, sizeof(phdr)))
goto end_coredump;
}
if (!elf_core_write_extra_phdrs(cprm, offset))
goto end_coredump;
/* write out the notes section */
if (!write_note_info(&info, cprm))
goto end_coredump;
/* For cell spufs and x86 xstate */
if (elf_coredump_extra_notes_write(cprm))
goto end_coredump;
/* Align to page */
dump_skip_to(cprm, dataoff);
for (i = 0; i < cprm->vma_count; i++) {
struct core_vma_metadata *meta = cprm->vma_meta + i;
if (!dump_user_range(cprm, meta->start, meta->dump_size))
goto end_coredump;
}
if (!elf_core_write_extra_data(cprm))
goto end_coredump;
if (e_phnum == PN_XNUM) {
if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
goto end_coredump;
}
end_coredump:
free_note_info(&info);
kfree(shdr4extnum);
kfree(phdr4note);
return has_dumped;
}
#endif /* CONFIG_ELF_CORE */
static int __init init_elf_binfmt(void)
{
register_binfmt(&elf_format);
return 0;
}
static void __exit exit_elf_binfmt(void)
{
/* Remove the COFF and ELF loaders. */
unregister_binfmt(&elf_format);
}
core_initcall(init_elf_binfmt);
module_exit(exit_elf_binfmt);
#ifdef CONFIG_BINFMT_ELF_KUNIT_TEST
#include "tests/binfmt_elf_kunit.c"
#endif
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