[PATCH] apparmor: fix off-by-one comparison on MAXMAPPED_SIG

[PATCH] apparmor: fix off-by-one comparison on MAXMAPPED_SIG

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

There is a an off-by-one comparision on sig against MAXMAPPED_SIG
that can lead to a read outside the sig_map array if sig
is MAXMAPPED_SIG. Fix this.

Detected with cppcheck:
"Either the condition 'sig<=35' is redundant or the array 'sig_map[35]'
is accessed at index 35, which is out of bounds."

Fixes: c6bf1adaecaa ("apparmor: add the ability to mediate signals")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 security/apparmor/ipc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/apparmor/ipc.c b/security/apparmor/ipc.c
index 66fb9ede9447..5091c78062e4 100644
--- a/security/apparmor/ipc.c
+++ b/security/apparmor/ipc.c
@@ -128,7 +128,7 @@ static inline int map_signal_num(int sig)
 		return SIGUNKNOWN;
 	else if (sig >= SIGRTMIN)
 		return sig - SIGRTMIN + 128;	/* rt sigs mapped to 128 */
-	else if (sig <= MAXMAPPED_SIG)
+	else if (sig < MAXMAPPED_SIG)
 		return sig_map[sig];
 	return SIGUNKNOWN;
 }
-- 
2.14.1

--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info@ http://vger.kernel.org/majordomo-info.html

[PATCH] apparmor: fix off-by-one comparison on MAXMAPPED_SIG

[John Johansen]

On 08/22/2017 05:58 PM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> There is a an off-by-one comparision on sig against MAXMAPPED_SIG
> that can lead to a read outside the sig_map array if sig
> is MAXMAPPED_SIG. Fix this.
> 
> Detected with cppcheck:
> "Either the condition 'sig<=35' is redundant or the array 'sig_map[35]'
> is accessed at index 35, which is out of bounds."
> 
> Fixes: c6bf1adaecaa ("apparmor: add the ability to mediate signals")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  security/apparmor/ipc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/security/apparmor/ipc.c b/security/apparmor/ipc.c
> index 66fb9ede9447..5091c78062e4 100644
> --- a/security/apparmor/ipc.c
> +++ b/security/apparmor/ipc.c
> @@ -128,7 +128,7 @@ static inline int map_signal_num(int sig)
>  		return SIGUNKNOWN;
>  	else if (sig >= SIGRTMIN)
>  		return sig - SIGRTMIN + 128;	/* rt sigs mapped to 128 */
> -	else if (sig <= MAXMAPPED_SIG)
> +	else if (sig < MAXMAPPED_SIG)
>  		return sig_map[sig];
>  	return SIGUNKNOWN;
>  }
> 

I've pulled this in to apparmor-next

--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html