x86/boot: Check if the input parameter (buffer) of the function is a null pointer

[PATCH] x86/boot: Check if the input parameter (buffer) of the function is a null pointer

Posted by Liam Ni 2 years, 9 months ago

If the variable buffer is a null pointer, it may cause the kernel to crash.

Signed-off-by: Liam Ni <zhiguangni01@gmail.com>
---
 arch/x86/boot/cmdline.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c
index 21d56ae83cdf..d0809f66054c 100644
--- a/arch/x86/boot/cmdline.c
+++ b/arch/x86/boot/cmdline.c
@@ -39,7 +39,7 @@ int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *b
 		st_bufcpy	/* Copying this to buffer */
 	} state = st_wordstart;
 
-	if (!cmdline_ptr)
+	if (!cmdline_ptr || buffer == NULL)
 		return -1;      /* No command line */
 
 	cptr = cmdline_ptr & 0xf;
-- 
2.25.1

Re: [PATCH] x86/boot: Check if the input parameter (buffer) of the function is a null pointer

Posted by Ingo Molnar 2 years, 8 months ago

* Liam Ni <zhiguangni01@gmail.com> wrote:

> If the variable buffer is a null pointer, it may cause the kernel to crash.
> 
> Signed-off-by: Liam Ni <zhiguangni01@gmail.com>
> ---
>  arch/x86/boot/cmdline.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c
> index 21d56ae83cdf..d0809f66054c 100644
> --- a/arch/x86/boot/cmdline.c
> +++ b/arch/x86/boot/cmdline.c
> @@ -39,7 +39,7 @@ int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *b
>  		st_bufcpy	/* Copying this to buffer */
>  	} state = st_wordstart;
>  
> -	if (!cmdline_ptr)
> +	if (!cmdline_ptr || buffer == NULL)
>  		return -1;      /* No command line */

Can this ever happen?

Thanks,

	Ingo