[git commit] udhcpc: fix segmentation fault on empty bin opt

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=1f1988d5256c9705a4f296ed48cdb7e463525ba4
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

The following caused udhcpc to segfault:
  busybox udhcpc -i lo -s /dev/null -x 0x3d:

function                                             old     new   delta
udhcp_str2optset                                     629     641     +12

Signed-off-by: Michal Kazior <michal at plume.com>
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 networking/udhcp/common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c
index 4a452cdb9..9ec752dfc 100644
--- a/networking/udhcp/common.c
+++ b/networking/udhcp/common.c
@@ -539,7 +539,7 @@ int FAST_FUNC udhcp_str2optset(const char *const_str, void *arg,
 
 		if (optflag->flags == OPTION_BIN) {
 			val = strtok(NULL, ""); /* do not split "'q w e'" */
-			trim(val);
+			if (val) trim(val);
 		} else
 			val = strtok(NULL, ", \t");
 		if (!val)