From 1b4b4b7f8d4443c3e630838c9b33c9a69fdb6193 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nforro@redhat.com>
Date: Sun, 19 Jun 2016 17:12:01 +0200
Subject: [PATCH] api.c: fix potential buffer overflow
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It is assumed that arguments read from /proc/<pid>/cmdline don't exceed
buf_pname buffer size, which is FILENAME_MAX - 1 characters, but that's
not always the case.

Add check to prevent buffer overflow and discard the excessive part of
an argument.

Signed-off-by: Nikola Forró <nforro@redhat.com>
---
 src/api.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/api.c b/src/api.c
index b40364c..18ce21f 100644
--- a/src/api.c
+++ b/src/api.c
@@ -4055,13 +4055,17 @@ static int cg_get_procname_from_proc_cmdline(pid_t pid,
 
 	while (c != EOF) {
 		c = fgetc(f);
-		if ((c != EOF) && (c != '\0')) {
+		if ((c != EOF) && (c != '\0') && (len < FILENAME_MAX - 1)) {
 			buf_pname[len] = c;
 			len++;
 			continue;
 		}
 		buf_pname[len] = '\0';
 
+		if (len == FILENAME_MAX - 1)
+			while ((c != EOF) && (c != '\0'))
+				c = fgetc(f);
+
 		/*
 		 * The taken process name from /proc/<pid>/status is
 		 * shortened to 15 characters if it is over. So the
-- 
2.7.4