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From:   =?utf-8?q?Thomas_Wei=C3=9Fschuh?= <linux@weissschuh.net>
Date:   Tue, 01 Aug 2023 07:30:16 +0200
Subject: [PATCH v2 09/10] selftests/nolibc: test return value of read() in
 test_vfprintf
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Message-Id: <20230801-nolibc-warnings-v2-9-1ba5ca57bd9b@weissschuh.net>
References: <20230801-nolibc-warnings-v2-0-1ba5ca57bd9b@weissschuh.net>
In-Reply-To: <20230801-nolibc-warnings-v2-0-1ba5ca57bd9b@weissschuh.net>
To:     Willy Tarreau <w@1wt.eu>, Shuah Khan <shuah@kernel.org>
Cc:     linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
        Yuan Tan <tanyuan@tinylab.org>,
        Zhangjin Wu <falcon@tinylab.org>,
        =?utf-8?q?Thomas_Wei=C3=9Fschuh?= <linux@weissschuh.net>
Precedence: bulk

If read() fails and returns -1 buf would be accessed out of bounds.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 tools/testing/selftests/nolibc/nolibc-test.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 82714051c72f..a334f8450a34 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -1031,6 +1031,12 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm
 	lseek(fd, 0, SEEK_SET);
 
 	r = read(fd, buf, sizeof(buf) - 1);
+	if (r == -1) {
+		llen += printf(" read() = %s", errorname(errno));
+		result(llen, FAIL);
+		return 1;
+	}
+
 	buf[r] = '\0';
 
 	fclose(memfile);

-- 
2.41.0