MIPS: fw: Allow firmware to pass a empty env

FlyGoat · tsbogend · commit ee1809ed7bc4 · 2023-04-12T15:07:36.000+02:00
fw_getenv will use env entry to determine style of env, however it is legal for firmware to just pass a empty list. Check if first entry exist before running strchr to avoid null pointer dereference. Cc: stable@vger.kernel.org Link: clbr/n64bootloader#5 Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
diff --git a/arch/mips/fw/lib/cmdline.c b/arch/mips/fw/lib/cmdline.c
@@ -53,7 +53,7 @@ char *fw_getenv(char *envname)
 {
 	char *result = NULL;
 
-	if (_fw_envp != NULL) {
+	if (_fw_envp != NULL && fw_envp(0) != NULL) {
 		/*
 		 * Return a pointer to the given environment variable.
 		 * YAMON uses "name", "value" pairs, while U-Boot uses

Original file line number	Diff line number	Diff line change
`@@ -53,7 +53,7 @@ char fw_getenv(char envname)`
`53`	`53`	`{`
`54`	`54`	`char *result = NULL;`
`55`	`55`
`56`		`- if (_fw_envp != NULL) {`
	`56`	`+ if (_fw_envp != NULL && fw_envp(0) != NULL) {`
`57`	`57`	`/*`
`58`	`58`	`* Return a pointer to the given environment variable.`
`59`	`59`	`* YAMON uses "name", "value" pairs, while U-Boot uses`