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authorXin Long <lucien.xin@gmail.com>2023-04-10 15:43:30 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-04-20 12:10:26 +0200
commit79b28f42214a3d0d6a8c514db3602260bd5d6cb5 (patch)
treedd2ba35399647c1380716e6543a5a46db5d1c0a2
parent3814d211ff13ee35f2d9437439a6c7df58524137 (diff)
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sctp: fix a potential overflow in sctp_ifwdtsn_skip
[ Upstream commit 32832a2caf82663870126c5186cf8f86c8b2a649 ] Currently, when traversing ifwdtsn skips with _sctp_walk_ifwdtsn, it only checks the pos against the end of the chunk. However, the data left for the last pos may be < sizeof(struct sctp_ifwdtsn_skip), and dereference it as struct sctp_ifwdtsn_skip may cause coverflow. This patch fixes it by checking the pos against "the end of the chunk - sizeof(struct sctp_ifwdtsn_skip)" in sctp_ifwdtsn_skip, similar to sctp_fwdtsn_skip. Fixes: 0fc2ea922c8a ("sctp: implement validate_ftsn for sctp_stream_interleave") Signed-off-by: Xin Long <lucien.xin@gmail.com> Link: https://lore.kernel.org/r/2a71bffcd80b4f2c61fac6d344bb2f11c8fd74f7.1681155810.git.lucien.xin@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--net/sctp/stream_interleave.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/sctp/stream_interleave.c b/net/sctp/stream_interleave.c
index 6b13f737ebf2..e3aad75cb11d 100644
--- a/net/sctp/stream_interleave.c
+++ b/net/sctp/stream_interleave.c
@@ -1162,7 +1162,8 @@ static void sctp_generate_iftsn(struct sctp_outq *q, __u32 ctsn)
#define _sctp_walk_ifwdtsn(pos, chunk, end) \
for (pos = chunk->subh.ifwdtsn_hdr->skip; \
- (void *)pos < (void *)chunk->subh.ifwdtsn_hdr->skip + (end); pos++)
+ (void *)pos <= (void *)chunk->subh.ifwdtsn_hdr->skip + (end) - \
+ sizeof(struct sctp_ifwdtsn_skip); pos++)
#define sctp_walk_ifwdtsn(pos, ch) \
_sctp_walk_ifwdtsn((pos), (ch), ntohs((ch)->chunk_hdr->length) - \