From: Kees Cook <keescook@chromium.org>
To: Alexei Starovoitov <ast@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: [PATCH bpf-next v2 1/3] bpf/verifier: Fix potential memory leak in array reallocation
Date: Fri, 28 Oct 2022 19:54:30 -0700 [thread overview]
Message-ID: <20221029025433.2533810-1-keescook@chromium.org> (raw)
In-Reply-To: <20221029024444.gonna.633-kees@kernel.org>
If an error (NULL) is returned by krealloc(), callers of realloc_array()
were setting their allocation pointers to NULL, but on error krealloc()
does not touch the original allocation. This would result in a memory
resource leak. Instead, free the old allocation on the error handling
path.
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: bpf@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
kernel/bpf/verifier.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 014ee0953dbd..eb8c34db74c7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1027,12 +1027,17 @@ static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t
*/
static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size)
{
+ void *new_arr;
+
if (!new_n || old_n == new_n)
goto out;
- arr = krealloc_array(arr, new_n, size, GFP_KERNEL);
- if (!arr)
+ new_arr = krealloc_array(arr, new_n, size, GFP_KERNEL);
+ if (!new_arr) {
+ kfree(arr);
return NULL;
+ }
+ arr = new_arr;
if (new_n > old_n)
memset(arr + old_n * size, 0, (new_n - old_n) * size);
--
2.34.1
next prev parent reply other threads:[~2022-10-29 2:55 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-29 2:54 [PATCH bpf-next v2 0/3] bpf/verifier: Use kmalloc_size_roundup() to match ksize() usage Kees Cook
2022-10-29 2:54 ` Kees Cook [this message]
2022-10-31 20:16 ` [PATCH bpf-next v2 1/3] bpf/verifier: Fix potential memory leak in array reallocation Bill Wendling
2022-11-01 13:46 ` Daniel Borkmann
2022-11-15 16:07 ` Lorenz Bauer
2022-10-29 2:54 ` [PATCH bpf-next v2 2/3] bpf/verifier: Use kmalloc_size_roundup() to match ksize() usage Kees Cook
2022-11-01 13:52 ` Daniel Borkmann
2022-11-01 17:01 ` Kees Cook
2022-10-29 2:54 ` [PATCH bpf-next v2 3/3] bpf/verifier: Take advantage of full allocation sizes Kees Cook
2022-10-31 21:53 ` Stanislav Fomichev
2022-11-01 5:23 ` Kees Cook
2022-11-01 13:40 ` [PATCH bpf-next v2 0/3] bpf/verifier: Use kmalloc_size_roundup() to match ksize() usage patchwork-bot+netdevbpf
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