From: Darrick J. Wong <darrick.wong@oracle.com>
Date: Sat, 9 May 2020 17:09:44 +0000 (-0400)
Subject: libxcmd: don't crash if el_gets returns null
X-Git-Tag: xfsprogs-5.7-fixes_2020-06-25~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b0c0cdb7ed8ee981e14fab8c23ec86bb2cc64aec;p=thirdparty%2Fxfsprogs-dev.git

libxcmd: don't crash if el_gets returns null

el_gets returns NULL if it fails to read any characters (due to EOF or
errors occurred).  strdup will crash if it is fed a NULL string, so
check the return value to avoid segfaulting.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
---

diff --git a/libxcmd/input.c b/libxcmd/input.c
index 203110df7..e3fa626a7 100644
--- a/libxcmd/input.c
+++ b/libxcmd/input.c
@@ -33,6 +33,7 @@ fetchline(void)
 	static EditLine	*el;
 	static History	*hist;
 	HistEvent	hevent;
+	const char	*cmd;
 	char		*line;
 	int		count;
 
@@ -45,13 +46,18 @@ fetchline(void)
 		el_set(el, EL_PROMPT, el_get_prompt);
 		el_set(el, EL_HIST, history, (const char *)hist);
 	}
-	line = strdup(el_gets(el, &count));
-	if (line) {
-		if (count > 0)
-			line[count-1] = '\0';
-		if (*line)
-			history(hist, &hevent, H_ENTER, line);
-	}
+	cmd = el_gets(el, &count);
+	if (!cmd)
+		return NULL;
+
+	line = strdup(cmd);
+	if (!line)
+		return NULL;
+
+	if (count > 0)
+		line[count-1] = '\0';
+	if (*line)
+		history(hist, &hevent, H_ENTER, line);
 	return line;
 }
 #else