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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, sam <sunhaoyl@outlook.com>,
        Alexander Potapenko <glider@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 101/142] fs/binfmt_elf.c: allocate initialized memory in fill_thread_core_info()
Date:   Mon,  1 Jun 2020 19:54:19 +0200
Message-Id: <20200601174048.446359312@linuxfoundation.org>
In-Reply-To: <20200601174037.904070960@linuxfoundation.org>
References: <20200601174037.904070960@linuxfoundation.org>
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From: Alexander Potapenko <glider@google.com>

[ Upstream commit 1d605416fb7175e1adf094251466caa52093b413 ]

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.

Reported-by: sam <sunhaoyl@outlook.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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>
Link: http://lkml.kernel.org/r/20200419100848.63472-1-glider@google.com
Link: https://github.com/google/kmsan/issues/76
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/binfmt_elf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index c5642bcb6b46..7ce3cfd965d2 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1731,7 +1731,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 		    (!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,
-- 
2.25.1