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[4/5] fs/binfmt_elf.c: allocate initialized memory in fill_thread_core_info()

Message ID 20200528052052.tLpI_z4pp%akpm@linux-foundation.org
State New, archived
Headers show
Series [1/5] mm/z3fold: silence kmemleak false positives of slots | expand

Commit Message

Andrew Morton May 28, 2020, 5:20 a.m. UTC
From: Alexander Potapenko <glider@google.com>
Subject: fs/binfmt_elf.c: allocate initialized memory in fill_thread_core_info()

KMSAN reported uninitialized data being written to disk when dumping core.
As a result, several kilobytes of kmalloc memory may be written to the
core file and then read by a non-privileged user.

Link: http://lkml.kernel.org/r/20200419100848.63472-1-glider@google.com
Link: https://github.com/google/kmsan/issues/76
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: sam <sunhaoyl@outlook.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

 fs/binfmt_elf.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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--- a/fs/binfmt_elf.c~fs-binfmt_elfc-allocate-initialized-memory-in-fill_thread_core_info
+++ a/fs/binfmt_elf.c
@@ -1733,7 +1733,7 @@  static int fill_thread_core_info(struct
 		    (!regset->active || regset->active(t->task, regset) > 0)) {
 			int ret;
 			size_t size = regset_size(t->task, regset);
-			void *data = kmalloc(size, GFP_KERNEL);
+			void *data = kzalloc(size, GFP_KERNEL);
 			if (unlikely(!data))
 				return 0;
 			ret = regset->get(t->task, regset,