[PATCH v2 09/16] coredump: Proactively round up to kmalloc bucket size
From: Kees Cook <hidden>
Date: 2022-09-23 20:34:52
Also in:
dri-devel, intel-wired-lan, linux-btrfs, linux-fsdevel, linux-hardening, linux-media, linux-mm, lkml, llvm
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
Instead of discovering the kmalloc bucket size _after_ allocation, round up proactively so the allocation is explicitly made for the full size, allowing the compiler to correctly reason about the resulting size of the buffer through the existing __alloc_size() hint. Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Kees Cook <redacted> --- fs/coredump.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/coredump.c b/fs/coredump.c
index 9f4aae202109..0894b2c35d98 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c@@ -68,7 +68,10 @@ struct core_name { static int expand_corename(struct core_name *cn, int size) { - char *corename = krealloc(cn->corename, size, GFP_KERNEL); + char *corename; + + size = kmalloc_size_roundup(size); + corename = krealloc(cn->corename, size, GFP_KERNEL); if (!corename) return -ENOMEM;
@@ -76,7 +79,7 @@ static int expand_corename(struct core_name *cn, int size) if (size > core_name_size) /* racy but harmless */ core_name_size = size; - cn->size = ksize(corename); + cn->size = size; cn->corename = corename; return 0; }
--
2.34.1