diff mbox series

[06/12] coredump: Proactively round up to kmalloc bucket size

Message ID 20220922031013.2150682-7-keescook@chromium.org (mailing list archive)
State Not Applicable
Delegated to: Johannes Berg
Headers show
Series slab: Introduce kmalloc_size_roundup() | expand

Commit Message

Kees Cook Sept. 22, 2022, 3:10 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: 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 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;
 }