* [PATCH] Smack: fix a dereference before null check on sock->sk
@ 2017-02-09 12:03 Colin King
2017-02-09 13:09 ` walter harms
0 siblings, 1 reply; 3+ messages in thread
From: Colin King @ 2017-02-09 12:03 UTC (permalink / raw)
To: Casey Schaufler, James Morris, Serge E . Hallyn,
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.
Detected with CoverityScan, CID#1324196 ("Dereference before null check")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
security/smack/smack_lsm.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index fc8fb31..bb17387 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2899,7 +2899,7 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
#endif
#ifdef SMACK_IPV6_SECMARK_LABELING
struct smack_known *rsp;
- struct socket_smack *ssp = sock->sk->sk_security;
+ struct socket_smack *ssp;
#endif
if (sock->sk == NULL)
@@ -2916,9 +2916,11 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
return -EINVAL;
#ifdef SMACK_IPV6_SECMARK_LABELING
rsp = smack_ipv6host_label(sip);
- if (rsp != NULL)
+ if (rsp != NULL) {
+ 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 related [flat|nested] 3+ messages in thread* Re: [PATCH] Smack: fix a dereference before null check on sock->sk
2017-02-09 12:03 [PATCH] Smack: fix a dereference before null check on sock->sk Colin King
@ 2017-02-09 13:09 ` walter harms
2017-02-09 16:49 ` Casey Schaufler
0 siblings, 1 reply; 3+ messages in thread
From: walter harms @ 2017-02-09 13:09 UTC (permalink / raw)
To: Colin King
Cc: Casey Schaufler, James Morris, Serge E . Hallyn,
linux-security-module, kernel-janitors, linux-kernel
Am 09.02.2017 13:03, schrieb Colin King:
> 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.
>
> Detected with CoverityScan, CID#1324196 ("Dereference before null check")
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> security/smack/smack_lsm.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index fc8fb31..bb17387 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -2899,7 +2899,7 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
> #endif
> #ifdef SMACK_IPV6_SECMARK_LABELING
> struct smack_known *rsp;
> - struct socket_smack *ssp = sock->sk->sk_security;
> + struct socket_smack *ssp;
> #endif
>
> if (sock->sk == NULL)
> @@ -2916,9 +2916,11 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
> return -EINVAL;
> #ifdef SMACK_IPV6_SECMARK_LABELING
> rsp = smack_ipv6host_label(sip);
> - if (rsp != NULL)
> + if (rsp != NULL) {
> + 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);
In the hope of reducing the ifdef forrest:
you could move the struct smack_known *rsp; and struct socket_smack *ssp; into the block like:
{
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);
}
}
just my 2 cents ...
re,
wh
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] Smack: fix a dereference before null check on sock->sk
2017-02-09 13:09 ` walter harms
@ 2017-02-09 16:49 ` Casey Schaufler
0 siblings, 0 replies; 3+ messages in thread
From: Casey Schaufler @ 2017-02-09 16:49 UTC (permalink / raw)
To: wharms, Colin King
Cc: James Morris, Serge E . Hallyn, linux-security-module,
kernel-janitors, linux-kernel
On 2/9/2017 5:09 AM, walter harms wrote:
>
> Am 09.02.2017 13:03, schrieb Colin King:
>> 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.
>>
>> Detected with CoverityScan, CID#1324196 ("Dereference before null check")
>>
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>> security/smack/smack_lsm.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
>> index fc8fb31..bb17387 100644
>> --- a/security/smack/smack_lsm.c
>> +++ b/security/smack/smack_lsm.c
>> @@ -2899,7 +2899,7 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
>> #endif
>> #ifdef SMACK_IPV6_SECMARK_LABELING
>> struct smack_known *rsp;
>> - struct socket_smack *ssp = sock->sk->sk_security;
>> + struct socket_smack *ssp;
>> #endif
>>
>> if (sock->sk == NULL)
>> @@ -2916,9 +2916,11 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
>> return -EINVAL;
>> #ifdef SMACK_IPV6_SECMARK_LABELING
>> rsp = smack_ipv6host_label(sip);
>> - if (rsp != NULL)
>> + if (rsp != NULL) {
>> + 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);
>
> In the hope of reducing the ifdef forrest:
> you could move the struct smack_known *rsp; and struct socket_smack *ssp; into the block like:
>
> {
> 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);
> }
> }
>
>
> just my 2 cents ...
I can't say that I'm proud of that chunk of code.
A real clean-up is on my todo list, and I would happily
entertain patches.
>
> re,
> wh
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-02-09 12:03 [PATCH] Smack: fix a dereference before null check on sock->sk Colin King
2017-02-09 13:09 ` walter harms
2017-02-09 16:49 ` Casey Schaufler
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