* [PATCH][V2] Smack: fix a dereference before null check on sock->sk
@ 2017-02-09 17:11 Colin King
2017-02-09 18:44 ` Casey Schaufler
0 siblings, 1 reply; 3+ messages in thread
From: Colin King @ 2017-02-09 17:11 UTC (permalink / raw)
To: Casey Schaufler, James Morris, Serge E . Hally, linux-security-module
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
The initialisation of pointer ssp is from a dereference on sock->sk
before sock-sk is null checked, hence there is a potential for a
null pointer deference. Fix this by moving the assignment of ssp
to just before it is used in the call to smk_ipv6_check.
Also minor clean up of code to reduce #ifdef noise.
Detected with CoverityScan, CID#1324196 ("Dereference before null check")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
security/smack/smack_lsm.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index fc8fb31..0c5656d 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2897,10 +2897,6 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
#if IS_ENABLED(CONFIG_IPV6)
struct sockaddr_in6 *sip = (struct sockaddr_in6 *)sap;
#endif
-#ifdef SMACK_IPV6_SECMARK_LABELING
- struct smack_known *rsp;
- struct socket_smack *ssp = sock->sk->sk_security;
-#endif
if (sock->sk == NULL)
return 0;
@@ -2915,10 +2911,17 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
if (addrlen < sizeof(struct sockaddr_in6))
return -EINVAL;
#ifdef SMACK_IPV6_SECMARK_LABELING
- rsp = smack_ipv6host_label(sip);
- if (rsp != NULL)
- rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
- SMK_CONNECTING);
+ {
+ struct smack_known *rsp = smack_ipv6host_label(sip);
+
+ if (rsp != NULL) {
+ struct socket_smack *ssp =
+ sock->sk->sk_security;
+
+ rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
+ SMK_CONNECTING);
+ }
+ }
#endif
#ifdef SMACK_IPV6_PORT_LABELING
rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING);
--
2.10.2
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH][V2] Smack: fix a dereference before null check on sock->sk
2017-02-09 17:11 [PATCH][V2] Smack: fix a dereference before null check on sock->sk Colin King
@ 2017-02-09 18:44 ` Casey Schaufler
2017-02-09 18:45 ` Colin Ian King
0 siblings, 1 reply; 3+ messages in thread
From: Casey Schaufler @ 2017-02-09 18:44 UTC (permalink / raw)
To: Colin King, James Morris, Serge E . Hally, linux-security-module
Cc: kernel-janitors, linux-kernel
On 2/9/2017 9:11 AM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> The initialisation of pointer ssp is from a dereference on sock->sk
> before sock-sk is null checked, hence there is a potential for a
> null pointer deference. Fix this by moving the assignment of ssp
> to just before it is used in the call to smk_ipv6_check.
>
> Also minor clean up of code to reduce #ifdef noise.
> Detected with CoverityScan, CID#1324196 ("Dereference before null check")
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> security/smack/smack_lsm.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index fc8fb31..0c5656d 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -2897,10 +2897,6 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
> #if IS_ENABLED(CONFIG_IPV6)
> struct sockaddr_in6 *sip = (struct sockaddr_in6 *)sap;
> #endif
> -#ifdef SMACK_IPV6_SECMARK_LABELING
> - struct smack_known *rsp;
> - struct socket_smack *ssp = sock->sk->sk_security;
> -#endif
>
> if (sock->sk == NULL)
> return 0;
> @@ -2915,10 +2911,17 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
> if (addrlen < sizeof(struct sockaddr_in6))
> return -EINVAL;
> #ifdef SMACK_IPV6_SECMARK_LABELING
> - rsp = smack_ipv6host_label(sip);
> - if (rsp != NULL)
> - rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
> - SMK_CONNECTING);
> + {
> + struct smack_known *rsp = smack_ipv6host_label(sip);
I make a habit of not using nested declarations.
I appreciate the intent of the patch, but I would
rather take a more global approach to the cleanup.
> +
> + if (rsp != NULL) {
> + struct socket_smack *ssp =
> + sock->sk->sk_security;
> +
> + rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
> + SMK_CONNECTING);
> + }
> + }
> #endif
> #ifdef SMACK_IPV6_PORT_LABELING
> rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING);
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH][V2] Smack: fix a dereference before null check on sock->sk
2017-02-09 18:44 ` Casey Schaufler
@ 2017-02-09 18:45 ` Colin Ian King
0 siblings, 0 replies; 3+ messages in thread
From: Colin Ian King @ 2017-02-09 18:45 UTC (permalink / raw)
To: Casey Schaufler, James Morris, Serge E . Hally, linux-security-module
Cc: kernel-janitors, linux-kernel
On 09/02/17 18:44, Casey Schaufler wrote:
> On 2/9/2017 9:11 AM, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> The initialisation of pointer ssp is from a dereference on sock->sk
>> before sock-sk is null checked, hence there is a potential for a
>> null pointer deference. Fix this by moving the assignment of ssp
>> to just before it is used in the call to smk_ipv6_check.
>>
>> Also minor clean up of code to reduce #ifdef noise.
>> Detected with CoverityScan, CID#1324196 ("Dereference before null check")
>>
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>> security/smack/smack_lsm.c | 19 +++++++++++--------
>> 1 file changed, 11 insertions(+), 8 deletions(-)
>>
>> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
>> index fc8fb31..0c5656d 100644
>> --- a/security/smack/smack_lsm.c
>> +++ b/security/smack/smack_lsm.c
>> @@ -2897,10 +2897,6 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
>> #if IS_ENABLED(CONFIG_IPV6)
>> struct sockaddr_in6 *sip = (struct sockaddr_in6 *)sap;
>> #endif
>> -#ifdef SMACK_IPV6_SECMARK_LABELING
>> - struct smack_known *rsp;
>> - struct socket_smack *ssp = sock->sk->sk_security;
>> -#endif
>>
>> if (sock->sk == NULL)
>> return 0;
>> @@ -2915,10 +2911,17 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
>> if (addrlen < sizeof(struct sockaddr_in6))
>> return -EINVAL;
>> #ifdef SMACK_IPV6_SECMARK_LABELING
>> - rsp = smack_ipv6host_label(sip);
>> - if (rsp != NULL)
>> - rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
>> - SMK_CONNECTING);
>> + {
>> + struct smack_known *rsp = smack_ipv6host_label(sip);
>
> I make a habit of not using nested declarations.
> I appreciate the intent of the patch, but I would
> rather take a more global approach to the cleanup.
Yup. tad frustrating this, the original patch is now going to turn into
a larger change set, which was not my original intent in a trivial bug fix.
>
>> +
>> + if (rsp != NULL) {
>> + struct socket_smack *ssp =
>> + sock->sk->sk_security;
>> +
>> + rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
>> + SMK_CONNECTING);
>> + }
>> + }
>> #endif
>> #ifdef SMACK_IPV6_PORT_LABELING
>> rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING);
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-02-09 18:48 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2017-02-09 17:11 [PATCH][V2] Smack: fix a dereference before null check on sock->sk Colin King
2017-02-09 18:44 ` Casey Schaufler
2017-02-09 18:45 ` Colin Ian King
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