On 2/9/2017 9:11 AM, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> 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 <[email protected]>
> ---
> 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);
