[PATCH] nios2: force the string buffer NULL-terminated

[PATCH] nios2: force the string buffer NULL-terminated

[Wang Xiayang]

strncpy() does not ensure NULL-termination when the input string
size equals to the destination buffer size COMMAND_LINE_SIZE.
Besides, grep under arch/ with 'boot_command_line' shows
no other arch-specific code uses strncpy() when copying
boot_command_line.

Use strlcpy() instead.

This issue is identified by a Coccinelle script.

Signed-off-by: Wang Xiayang <xywang.sjtu@sjtu.edu.cn>
---
 arch/nios2/kernel/setup.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c
index 6bbd4ae2beb0..4cf35b09c0ec 100644
--- a/arch/nios2/kernel/setup.c
+++ b/arch/nios2/kernel/setup.c
@@ -123,7 +123,7 @@ asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
 		dtb_passed = r6;
 
 		if (r7)
-			strncpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
+			strlcpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
 	}
 #endif
 
@@ -131,10 +131,10 @@ asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
 
 #ifndef CONFIG_CMDLINE_FORCE
 	if (cmdline_passed[0])
-		strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
+		strlcpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
 	else
-		strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+		strlcpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 #endif
 #endif
 
-- 
2.11.0

Re: [PATCH] nios2: force the string buffer NULL-terminated

[Ley Foon Tan]

On Mon, 2019-08-05 at 18:17 +0800, Wang Xiayang wrote:
> strncpy() does not ensure NULL-termination when the input string
> size equals to the destination buffer size COMMAND_LINE_SIZE.
> Besides, grep under arch/ with 'boot_command_line' shows
> no other arch-specific code uses strncpy() when copying
> boot_command_line.
> 
> Use strlcpy() instead.
> 
> This issue is identified by a Coccinelle script.
> 
> Signed-off-by: Wang Xiayang <xywang.sjtu@sjtu.edu.cn>
Merged to v5.4-rc1. Thanks.


Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>


> ---
>  arch/nios2/kernel/setup.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c
> index 6bbd4ae2beb0..4cf35b09c0ec 100644
> --- a/arch/nios2/kernel/setup.c
> +++ b/arch/nios2/kernel/setup.c
> @@ -123,7 +123,7 @@ asmlinkage void __init nios2_boot_init(unsigned
> r4, unsigned r5, unsigned r6,
>                 dtb_passed = r6;
> 
>                 if (r7)
> -                       strncpy(cmdline_passed, (char *)r7,
> COMMAND_LINE_SIZE);
> +                       strlcpy(cmdline_passed, (char *)r7,
> COMMAND_LINE_SIZE);
>         }
>  #endif
> 
> @@ -131,10 +131,10 @@ asmlinkage void __init nios2_boot_init(unsigned
> r4, unsigned r5, unsigned r6,
> 
>  #ifndef CONFIG_CMDLINE_FORCE
>         if (cmdline_passed[0])
> -               strncpy(boot_command_line, cmdline_passed,
> COMMAND_LINE_SIZE);
> +               strlcpy(boot_command_line, cmdline_passed,
> COMMAND_LINE_SIZE);
>  #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
>         else
> -               strncpy(boot_command_line, CONFIG_CMDLINE,
> COMMAND_LINE_SIZE);
> +               strlcpy(boot_command_line, CONFIG_CMDLINE,
> COMMAND_LINE_SIZE);
>  #endif
>  #endif
> 
> --
> 2.11.0
> 
> 
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