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authorYu-Chun Lin <eleanor15x@gmail.com>2025-02-18 16:12:16 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-03-22 12:56:50 -0700
commite8e0141d4692689939341c13baa2b7b14add8611 (patch)
treeef0109afc484cb01fe886fef667f9ecd2cef143c /net
parent52a33f9f4a92e20ff83deed7c00cd232c869c3c8 (diff)
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sctp: Fix undefined behavior in left shift operation
[ Upstream commit 606572eb22c1786a3957d24307f5760bb058ca19 ] According to the C11 standard (ISO/IEC 9899:2011, 6.5.7): "If E1 has a signed type and E1 x 2^E2 is not representable in the result type, the behavior is undefined." Shifting 1 << 31 causes signed integer overflow, which leads to undefined behavior. Fix this by explicitly using '1U << 31' to ensure the shift operates on an unsigned type, avoiding undefined behavior. Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com> Link: https://patch.msgid.link/20250218081217.3468369-1-eleanor15x@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/sctp/stream.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index c241cc552e8d..bfcff6d6a438 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -735,7 +735,7 @@ struct sctp_chunk *sctp_process_strreset_tsnreq(
* value SHOULD be the smallest TSN not acknowledged by the
* receiver of the request plus 2^31.
*/
- init_tsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + (1 << 31);
+ init_tsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + (1U << 31);
sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
init_tsn, GFP_ATOMIC);