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(-)

--- 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, _