diff mbox series

coredump: Proactively round up to kmalloc bucket size

Message ID 20221018090701.never.996-kees@kernel.org (mailing list archive)
State Mainlined
Commit 6dd142d9013ca82155d0c069434c60a0d5755ec0
Headers show
Series coredump: Proactively round up to kmalloc bucket size | expand

Commit Message

Kees Cook Oct. 18, 2022, 9:07 a.m. UTC 
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: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/coredump.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/fs/coredump.c b/fs/coredump.c
index 7bad7785e8e6..97eaee325251 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;
 }