RDMA/siw: Bound fragmented header copies by the remaining length

siw_get_hdr() can receive an extended DDP/RDMAP header across more than
one TCP callback. The first callback may receive most of the header,
while the next one still limits the copy to hdrlen - MIN_DDP_HDR instead
of the number of missing bytes. This makes the destination move past the
end of the header and overwrite the receive state, including
fpdu_part_rcvd. A later callback can then use a negative fpdu_part_rcvd
value as a copy offset, which creates an OOB write.

Use the number of header bytes already received when calculating the
next copy length.

Fixes: 754209850d ("RDMA/siw: Always consume all skbuf data in sk_data_ready() upcall.")
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
Link: https://patch.msgid.link/20260908085520.1746329-1-Jeremy.Jean@oss.cyber.gouv.fr
Assisted-by: Codex:gpt-6
Acked-by: Bernard Metzler <bernard.metzler@linux.dev>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
This commit is contained in:
Jérémy Jean
2026-09-10 11:15:46 -04:00
committed by Leon Romanovsky
parent e22a3627b7
commit 9ff797e516
+1 -1
View File
@@ -1079,7 +1079,7 @@ static int siw_get_hdr(struct siw_rx_stream *srx)
if (iwarp_pktinfo[opcode].hdr_len > sizeof(struct iwarp_ctrl_tagged)) {
int hdrlen = iwarp_pktinfo[opcode].hdr_len;
bytes = min_t(int, hdrlen - MIN_DDP_HDR, srx->skb_new);
bytes = min_t(int, hdrlen - srx->fpdu_part_rcvd, srx->skb_new);
skb_copy_bits(skb, srx->skb_offset,
(char *)c_hdr + srx->fpdu_part_rcvd, bytes);