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b=r+Vj8IdcOLhJtUtOQzh254rqvzA3uB/Iye7mW2zJnKE1QoXEBJZwneCUmDAMQSl63 7mHUl0l92fNWBWeeNR/ikW1O6FbCag2yrnh5OAlaQatcoNr3zfCK1v1vsWF0FKqA9e 8dW4DoHYKeMyLD6z93jef3FZco/su92gf6Nicx2RFJvCeucfO27dUq1CzyC7hS+iqk EcdGcm2ALXOgaR4cdZ2/e2wMfGzFymM6111pCjwIosZnBu03Db/elcQmwAvLrq13b6 mWFkahThS0zCNqtezFIpfYCWQwbEcOoK5zKXviU67EWgtWFgfGtWx5itFIN2XzA6KP VHPAXFFU5J6ww== From: Kees Cook To: Vlastimil Babka Cc: Kees Cook , Vlastimil Babka , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] slab: Saturate to SIZE_MAX for allocation size overflows Date: Tue, 24 Feb 2026 17:40:02 -0800 Message-Id: <20260225013954.work.319-kees@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2209; i=kees@kernel.org; h=from:subject:message-id; bh=/vhqQFuGoe48JWJKQbmTtsW8NfhyeO+Zgc9RwDLnpHU=; b=owGbwMvMwCVmps19z/KJym7G02pJDJnzgj7G3faYZqv3iPHMylti0ey+N15vWpz6ovTHke3+h 5tZrvot6yhlYRDjYpAVU2QJsnOPc/F42x7uPlcRZg4rE8gQBi5OAZjI88+MDCunsujwCF3b7cWt PPPyMd6Dt4vilMQ8YxcqG4Ss/sta2sLwh2+H4YHUnGcW0Q+fx/zYL1XXriwetf+/ZkvAoY4MVi5 jBgA= X-Developer-Key: i=kees@kernel.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Stat-Signature: joac4uq9arf3rqdo1k7ik7txse68pm8b X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 58FC2A000E X-HE-Tag: 1771983605-928610 X-HE-Meta: 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 n8Jjm3NL 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Instead of silently returning NULL on size overflows from array allocations, saturate the request to SIZE_MAX so the error will be surfaced to the allocator (and still return NULL). Suggested-by: Vlastimil Babka Link: https://lore.kernel.org/lkml/a144cd1e-8bfc-4380-8f1b-071db0af0b2c@suse.cz/ Signed-off-by: Kees Cook --- Cc: Vlastimil Babka Cc: Andrew Morton Cc: Christoph Lameter Cc: David Rientjes Cc: Roman Gushchin Cc: Harry Yoo Cc: --- include/linux/slab.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index a5a5e4108ae5..8453c81c75c3 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -1105,7 +1105,7 @@ static inline __alloc_size(1, 2) void *kmalloc_array_noprof(size_t n, size_t siz size_t bytes; if (unlikely(check_mul_overflow(n, size, &bytes))) - return NULL; + bytes = SIZE_MAX; return kmalloc_noprof(bytes, flags); } #define kmalloc_array(...) alloc_hooks(kmalloc_array_noprof(__VA_ARGS__)) @@ -1135,7 +1135,7 @@ static inline __realloc_size(2, 3) void * __must_check krealloc_array_noprof(voi size_t bytes; if (unlikely(check_mul_overflow(new_n, new_size, &bytes))) - return NULL; + bytes = SIZE_MAX; return krealloc_noprof(p, bytes, flags); } @@ -1175,7 +1175,7 @@ static inline __alloc_size(1, 2) void *kmalloc_array_node_noprof(size_t n, size_ size_t bytes; if (unlikely(check_mul_overflow(n, size, &bytes))) - return NULL; + bytes = SIZE_MAX; if (__builtin_constant_p(n) && __builtin_constant_p(size)) return kmalloc_node_noprof(bytes, flags, node); return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(bytes, NULL), flags, node); @@ -1223,7 +1223,7 @@ kvmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, int node) size_t bytes; if (unlikely(check_mul_overflow(n, size, &bytes))) - return NULL; + bytes = SIZE_MAX; return kvmalloc_node_align_noprof(bytes, 1, flags, node); } -- 2.34.1