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b=r4l6bBR+x/wYLFdBSbtrGEd6woZznOFVZnH0r9s2erJWpuz7nykmFQVCQpBbw0PHi kBR6AJir9BuoO165Hel1lDGlfK/BIcg6S5gINxdT7rhP0fBX/nyAEUVlS8lJKw0Sau IJNrXe4OD7939BXLdQ8qB9qMLdPMw3QM4EQFodO2PPj4qmoTr6tG9z1u8daz/GGBIJ wLzSxhLIt3s7zxeHLaCuXB2ghbY4o5Mo9P4rs+A+HTZa5H96TnEWQLZq61NM1NAk3A jrNv2m1xnfwMfiPoZWq3tdUYE+jpmmGcmg4dP/kQZUTert0ZpVnmANvFht9GimNVB7 EwgZihfV2WUtw== Date: Sun, 9 Nov 2025 19:06:59 +0100 From: Alejandro Colomar To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Alejandro Colomar , Kees Cook , Christopher Bazley , Rasmus Villemoes , Marco Elver , Michal Hocko , Linus Torvalds , Al Viro , Alexander Potapenko , Dmitry Vyukov , Jann Horn , Andrew Morton Subject: [PATCH v3 2/4] mm: Fix benign off-by-one bugs Message-ID: <831155f02bec5ed4ef2be1d427ea18c46446c127.1762711279.git.alx@kernel.org> X-Mailer: git-send-email 2.51.0 References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Stat-Signature: xdehytsqx1631g5yqwtbji8jjzf6pino X-Rspam-User: X-Rspamd-Queue-Id: 0670AC0003 X-Rspamd-Server: rspam10 X-HE-Tag: 1762711624-917146 X-HE-Meta: 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 0cldM/Y8 /kMDJ4dMGBolnjKDHWgGMwdTyZb2qZ0p39kbhonJ3GX56E/DKvmSUohy7XHW1eplo/XhJysTLOGe6TSCYXYUsYxRHhmfJbLF/QTg1CpHjz/CvBzklRA2WDErnUDoiFMLvqRJXDBeydwYskbPTGlgiGIfc17iAsxF+sg1x/V1Fk3M2X20f5SWyiD6nlU5W6YflYQ22E4mnlfTVmcJU7S0PauiUxiAMeiYCTxdm3luZRRWmoLYiJrx6jm4wHT+paepbsTvHwfmZKCBOQDeuQ+xKOWni4Csor4Iq+50hnwH4GqmpivXILke0nLUGu0Agoeb/9gh27+9UN70RD/bi9HoWs1GVwjxMnRv8Od+6ZWKSlb13vpzeKzGWlh32/TEhXexg+OOg53V0NFhuYAkYuC+BMEIu1kUKnsFx/G0Fgp5x3IjSwC+sxMCskCLIxjWAKM19Mtdes4PSiaCTI5iKIwjwTwADLLiNqGBW44eImRx3hJ5tDMahSupLU5eHaZrfFakRhm/TsUm0JPgX0e/o1zRV4aGxEaF3n1zBiWTl X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: We were wasting a byte due to an off-by-one bug. s[c]nprintf() doesn't write more than $2 bytes including the null byte, so trying to pass 'size-1' there is wasting one byte. Acked-by: Marco Elver Cc: Kees Cook Cc: Christopher Bazley Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Alexander Potapenko Cc: Jann Horn Cc: Andrew Morton Cc: Linus Torvalds Cc: Rasmus Villemoes Cc: Marco Elver Cc: Michal Hocko Cc: Al Viro Signed-off-by: Alejandro Colomar Message-ID: <515445ae064d4b8599899bf0d8b480dadd2ff843.1752182685.git.alx@kernel.org> --- mm/kfence/kfence_test.c | 4 ++-- mm/kmsan/kmsan_test.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c index 00034e37bc9f..5725a367246d 100644 --- a/mm/kfence/kfence_test.c +++ b/mm/kfence/kfence_test.c @@ -110,7 +110,7 @@ static bool report_matches(const struct expect_report *r) /* Title */ cur = expect[0]; - end = &expect[0][sizeof(expect[0]) - 1]; + end = ARRAY_END(expect[0]); switch (r->type) { case KFENCE_ERROR_OOB: cur += scnprintf(cur, end - cur, "BUG: KFENCE: out-of-bounds %s", @@ -140,7 +140,7 @@ static bool report_matches(const struct expect_report *r) /* Access information */ cur = expect[1]; - end = &expect[1][sizeof(expect[1]) - 1]; + end = ARRAY_END(expect[1]); switch (r->type) { case KFENCE_ERROR_OOB: diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c index 902ec48b1e3e..b5ad5dfb2c00 100644 --- a/mm/kmsan/kmsan_test.c +++ b/mm/kmsan/kmsan_test.c @@ -105,7 +105,7 @@ static bool report_matches(const struct expect_report *r) /* Title */ cur = expected_header; - end = &expected_header[sizeof(expected_header) - 1]; + end = ARRAY_END(expected_header); cur += scnprintf(cur, end - cur, "BUG: KMSAN: %s", r->error_type); -- 2.51.0