[v1] apparmor: Replace memcpy + NUL termination with kmemdup_nul in do_setattr

[PATCH RESEND] apparmor: Replace memcpy + NUL termination with kmemdup_nul in do_setattr

Posted by Thorsten Blum 3 weeks, 3 days ago

Use kmemdup_nul() to copy 'value' instead of using memcpy() followed by
a manual NUL termination.  No functional changes.

Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 security/apparmor/lsm.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index c1d42fc72fdb..49aa6ad68838 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -858,12 +858,9 @@ static int do_setattr(u64 attr, void *value, size_t size)
 
 	/* AppArmor requires that the buffer must be null terminated atm */
 	if (args[size - 1] != '\0') {
-		/* null terminate */
-		largs = args = kmalloc(size + 1, GFP_KERNEL);
+		largs = args = kmemdup_nul(value, size, GFP_KERNEL);
 		if (!args)
 			return -ENOMEM;
-		memcpy(args, value, size);
-		args[size] = '\0';
 	}
 
 	error = -EINVAL;

Re: [PATCH RESEND] apparmor: Replace memcpy + NUL termination with kmemdup_nul in do_setattr

Posted by John Johansen 2 weeks, 1 day ago

On 3/9/26 15:41, Thorsten Blum wrote:
> Use kmemdup_nul() to copy 'value' instead of using memcpy() followed by
> a manual NUL termination.  No functional changes.
> 
> Reviewed-by: Serge Hallyn <serge@hallyn.com>
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>

sorry this got lost in the mess of the last month, this has
now been pulled into my tree


> ---
>   security/apparmor/lsm.c | 5 +----
>   1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> index c1d42fc72fdb..49aa6ad68838 100644
> --- a/security/apparmor/lsm.c
> +++ b/security/apparmor/lsm.c
> @@ -858,12 +858,9 @@ static int do_setattr(u64 attr, void *value, size_t size)
>   
>   	/* AppArmor requires that the buffer must be null terminated atm */
>   	if (args[size - 1] != '\0') {
> -		/* null terminate */
> -		largs = args = kmalloc(size + 1, GFP_KERNEL);
> +		largs = args = kmemdup_nul(value, size, GFP_KERNEL);
>   		if (!args)
>   			return -ENOMEM;
> -		memcpy(args, value, size);
> -		args[size] = '\0';
>   	}
>   
>   	error = -EINVAL;