From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Quentin Monnet , Jakub Kicinski , Daniel Borkmann , Sasha Levin Subject: [PATCH 4.19 032/142] tools: bpftool: prevent infinite loop in get_fdinfo() Date: Fri, 14 Dec 2018 12:58:37 +0100 Message-Id: <20181214115748.337244816@linuxfoundation.org> In-Reply-To: <20181214115747.053633987@linuxfoundation.org> References: <20181214115747.053633987@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit List-ID: 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 53909030aa29bffe1f8490df62176c2375135652 ] Function getline() returns -1 on failure to read a line, thus creating an infinite loop in get_fdinfo() if the key is not found. Fix it by calling the function only as long as we get a strictly positive return value. Found by copying the code for a key which is not always present... Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool") Signed-off-by: Quentin Monnet Reviewed-by: Jakub Kicinski Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin --- tools/bpf/bpftool/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index b3a0709ea7ed..fcaf00621102 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -304,7 +304,7 @@ char *get_fdinfo(int fd, const char *key) return NULL; } - while ((n = getline(&line, &line_n, fdi))) { + while ((n = getline(&line, &line_n, fdi)) > 0) { char *value; int len; -- 2.19.1