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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, Dan Carpenter <dan.carpenter@oracle.com>,
        Martin KaFai Lau <kafai@fb.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 0483/1095] selftests/bpf: fix a test for snprintf() overflow
Date:   Mon, 15 Aug 2022 19:58:02 +0200
Message-Id: <20220815180449.544839968@linuxfoundation.org>
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From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit c5d22f4cfe8dfb93f1db0a1e7e2e7ebc41395d98 ]

The snprintf() function returns the number of bytes which *would*
have been copied if there were space.  In other words, it can be
> sizeof(pin_path).

Fixes: c0fa1b6c3efc ("bpf: btf: Add BTF tests")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/YtZ+aD/tZMkgOUw+@kili
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/selftests/bpf/prog_tests/btf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c
index ec823561b912..a294176f8a9d 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf.c
@@ -5226,7 +5226,7 @@ static void do_test_pprint(int test_num)
 	ret = snprintf(pin_path, sizeof(pin_path), "%s/%s",
 		       "/sys/fs/bpf", test->map_name);
 
-	if (CHECK(ret == sizeof(pin_path), "pin_path %s/%s is too long",
+	if (CHECK(ret >= sizeof(pin_path), "pin_path %s/%s is too long",
 		  "/sys/fs/bpf", test->map_name)) {
 		err = -1;
 		goto done;
-- 
2.35.1