env: fix crash using default -f -a

env default -a -f calls env_check_apply on all existing environment
variables with a NULL value for "newval" as a way of cleaning up.
This causes string manipulation functions to crash on most architectures.
So replace a NULL argument with an empty string.

Reported-By: Stefano Babic <sbabic@denx.de>
Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Tested-by: Stefano Babic <sbabic@denx.de>

diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c
index 8ecc4982309874e4cbfe8c1c0b6e0dd0efb17010..bb1d4ec3e54df90a6df9d8ce7de7add30b1b3b90 100644 (file)
--- a/common/cmd_nvedit.c
+++ b/common/cmd_nvedit.c
@@ -215,6 +215,9 @@ int env_check_apply(const char *name, const char *oldval,
 {
        int   console = -1;
 
+       /* Default value for NULL to protect string-manipulating functions */
+       newval = newval ? : "";
+
        /* Check for console redirection */
        if (strcmp(name, "stdin") == 0)
                console = stdin;