[PATCH teavpn2 2/3] net: iface: Fix a potential NULL pointer dereference

[Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>]

The malloc() call in escapeshellarg() doesn't have a NULL check. This
results in a potential NULL pointer dereference. Fix this by checking
the return value of malloc(). Just return NULL directly if we hit the
ENOMEM case.

Fixes: 0cfd7f8b60a09000a4257015b592e79b0bd8b8bd ("net: rewire iface support for linux")
Cc: Ammar Faizi <ammarfaizi2@gmail.com>
Cc: Louvian Lyndal <louvianlyndal@gmail.com>
Cc: Michael Arminto <kohaku.mski@gmail.com>
Signed-off-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
---
 src/teavpn2/net/linux/iface.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/teavpn2/net/linux/iface.c b/src/teavpn2/net/linux/iface.c
index 010e195..a77c1c8 100644
--- a/src/teavpn2/net/linux/iface.c
+++ b/src/teavpn2/net/linux/iface.c
@@ -107,11 +107,14 @@ __cold static noinline char *escapeshellarg(char *alloc, const char *str,
 	size_t x;
 	char *cmd;
 
-	if (alloc == NULL)
+	if (alloc == NULL) {
 		/* Worst case */
 		cmd = (char *)malloc((sizeof(char) * l * 4) + 1);
-	else
+		if (!cmd)
+			return NULL;
+	} else {
 		cmd = alloc;
+	}
 
 #ifdef WIN32
 	cmd[y++] = '"';
-- 
Alviro Iskandar Setiawan