[PATCH] MIPS: fw: Allow firmware to pass a empty env

[PATCH] MIPS: fw: Allow firmware to pass a empty env

[Jiaxun Yang]

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: https://github.com/clbr/n64bootloader/issues/5
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
Note: Fixes tag is intentionally omitted for this patch, although
the booting issue only comes in 6.1, the logic issue is been since very start.
---
 arch/mips/fw/lib/cmdline.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/fw/lib/cmdline.c b/arch/mips/fw/lib/cmdline.c
index f24cbb4a39b5..892765b742bb 100644
--- 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
-- 
2.39.2 (Apple Git-143)

Re: [PATCH] MIPS: fw: Allow firmware to pass a empty env

[Thomas Bogendoerfer]

On Tue, Apr 11, 2023 at 12:14:26PM +0100, Jiaxun Yang wrote:
> 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: https://github.com/clbr/n64bootloader/issues/5
> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
> Note: Fixes tag is intentionally omitted for this patch, although
> the booting issue only comes in 6.1, the logic issue is been since very start.
> ---
>  arch/mips/fw/lib/cmdline.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/mips/fw/lib/cmdline.c b/arch/mips/fw/lib/cmdline.c
> index f24cbb4a39b5..892765b742bb 100644
> --- 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
> -- 
> 2.39.2 (Apple Git-143)

applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]