From: Kees Cook Date: Fri, 6 Jan 2023 06:02:33 +0000 (-0800) Subject: bcache: Silence memcpy() run-time false positive warnings X-Git-Tag: baikal/aarch64/sdk6.1~100 X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=97927df75a519c02879d8318f6bbbc1c60601db9;p=kernel.git bcache: Silence memcpy() run-time false positive warnings [ Upstream commit be0d8f48ad97f5b775b0af3310343f676dbf318a ] struct bkey has internal padding in a union, but it isn't always named the same (e.g. key ## _pad, key_p, etc). This makes it extremely hard for the compiler to reason about the available size of copies done against such keys. Use unsafe_memcpy() for now, to silence the many run-time false positive warnings: memcpy: detected field-spanning write (size 264) of single field "&i->j" at drivers/md/bcache/journal.c:152 (size 240) memcpy: detected field-spanning write (size 24) of single field "&b->key" at drivers/md/bcache/btree.c:939 (size 16) memcpy: detected field-spanning write (size 24) of single field "&temp.key" at drivers/md/bcache/extents.c:428 (size 16) Reported-by: Alexandre Pereira Link: https://bugzilla.kernel.org/show_bug.cgi?id=216785 Acked-by: Coly Li Cc: Kent Overstreet Cc: linux-bcache@vger.kernel.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20230106060229.never.047-kees@kernel.org Signed-off-by: Sasha Levin --- diff --git a/drivers/md/bcache/bcache_ondisk.h b/drivers/md/bcache/bcache_ondisk.h index 97413586195b4..f96034e0ba4f2 100644 --- a/drivers/md/bcache/bcache_ondisk.h +++ b/drivers/md/bcache/bcache_ondisk.h @@ -106,7 +106,8 @@ static inline unsigned long bkey_bytes(const struct bkey *k) return bkey_u64s(k) * sizeof(__u64); } -#define bkey_copy(_dest, _src) memcpy(_dest, _src, bkey_bytes(_src)) +#define bkey_copy(_dest, _src) unsafe_memcpy(_dest, _src, bkey_bytes(_src), \ + /* bkey is always padded */) static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src) { diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c index e5da469a42357..c182c21de2e81 100644 --- a/drivers/md/bcache/journal.c +++ b/drivers/md/bcache/journal.c @@ -149,7 +149,8 @@ add: bytes, GFP_KERNEL); if (!i) return -ENOMEM; - memcpy(&i->j, j, bytes); + unsafe_memcpy(&i->j, j, bytes, + /* "bytes" was calculated by set_bytes() above */); /* Add to the location after 'where' points to */ list_add(&i->list, where); ret = 1;