From: Quentin Monnet <quentin.monnet@netronome.com>
Date: Thu, 8 Nov 2018 11:52:25 +0000 (+0000)
Subject: tools: bpftool: prevent infinite loop in get_fdinfo()
X-Git-Tag: v4.19.10~112
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b42ab52844123694b7f0524be08c96c8408aaa37;p=platform%2Fkernel%2Flinux-rpi.git

tools: bpftool: prevent infinite loop in get_fdinfo()

[ 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 <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index b3a0709..fcaf006 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;