From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 23 Nov 2021 16:23:23 -0800
Subject: selftests/bpf: Prevent out-of-bounds stack access in test_bpffs
Patch-mainline: v5.17-rc1
Git-commit: 57428298b5acf2ba2dd98359c532774f6eaeecb3
References: jsc#PED-1377
Buf can be not zero-terminated leading to strstr() to access data beyond
the intended buf[] array. Fix by forcing zero termination.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211124002325.1737739-12-andrii@kernel.org
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/testing/selftests/bpf/prog_tests/test_bpffs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
@@ -19,11 +19,13 @@ static int read_iter(char *file)
fd = open(file, 0);
if (fd < 0)
return -1;
- while ((len = read(fd, buf, sizeof(buf))) > 0)
+ while ((len = read(fd, buf, sizeof(buf))) > 0) {
+ buf[sizeof(buf) - 1] = '\0';
if (strstr(buf, "iter")) {
close(fd);
return 0;
}
+ }
close(fd);
return -1;
}