From dc49c1f94e3469d94b952e8f5160dd4ccd791d79 Mon Sep 17 00:00:00 2001 From: Catherine Zhang Date: Wed, 2 Aug 2006 14:12:06 -0700 Subject: [AF_UNIX]: Kernel memory leak fix for af_unix datagram getpeersec patch From: Catherine Zhang This patch implements a cleaner fix for the memory leak problem of the original unix datagram getpeersec patch. Instead of creating a security context each time a unix datagram is sent, we only create the security context when the receiver requests it. This new design requires modification of the current unix_getsecpeer_dgram LSM hook and addition of two new hooks, namely, secid_to_secctx and release_secctx. The former retrieves the security context and the latter releases it. A hook is required for releasing the security context because it is up to the security module to decide how that's done. In the case of Selinux, it's a simple kfree operation. Acked-by: Stephen Smalley Signed-off-by: David S. Miller --- include/net/af_unix.h | 6 ++---- include/net/scm.h | 29 +++++++++++++++++++++++++---- 2 files changed, 27 insertions(+), 8 deletions(-) (limited to 'include/net') diff --git a/include/net/af_unix.h b/include/net/af_unix.h index 2fec827c880..c0398f5a8cb 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -54,15 +54,13 @@ struct unix_skb_parms { struct ucred creds; /* Skb credentials */ struct scm_fp_list *fp; /* Passed files */ #ifdef CONFIG_SECURITY_NETWORK - char *secdata; /* Security context */ - u32 seclen; /* Security length */ + u32 secid; /* Security ID */ #endif }; #define UNIXCB(skb) (*(struct unix_skb_parms*)&((skb)->cb)) #define UNIXCREDS(skb) (&UNIXCB((skb)).creds) -#define UNIXSECDATA(skb) (&UNIXCB((skb)).secdata) -#define UNIXSECLEN(skb) (&UNIXCB((skb)).seclen) +#define UNIXSID(skb) (&UNIXCB((skb)).secid) #define unix_state_rlock(s) spin_lock(&unix_sk(s)->lock) #define unix_state_runlock(s) spin_unlock(&unix_sk(s)->lock) diff --git a/include/net/scm.h b/include/net/scm.h index 02daa097cdc..5637d5e22d5 100644 --- a/include/net/scm.h +++ b/include/net/scm.h @@ -3,6 +3,7 @@ #include #include +#include /* Well, we should have at least one descriptor open * to accept passed FDs 8) @@ -20,8 +21,7 @@ struct scm_cookie struct ucred creds; /* Skb credentials */ struct scm_fp_list *fp; /* Passed files */ #ifdef CONFIG_SECURITY_NETWORK - char *secdata; /* Security context */ - u32 seclen; /* Security length */ + u32 secid; /* Passed security ID */ #endif unsigned long seq; /* Connection seqno */ }; @@ -32,6 +32,16 @@ extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie extern void __scm_destroy(struct scm_cookie *scm); extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl); +#ifdef CONFIG_SECURITY_NETWORK +static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm) +{ + security_socket_getpeersec_dgram(sock, NULL, &scm->secid); +} +#else +static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm) +{ } +#endif /* CONFIG_SECURITY_NETWORK */ + static __inline__ void scm_destroy(struct scm_cookie *scm) { if (scm && scm->fp) @@ -47,6 +57,7 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg, scm->creds.pid = p->tgid; scm->fp = NULL; scm->seq = 0; + unix_get_peersec_dgram(sock, scm); if (msg->msg_controllen <= 0) return 0; return __scm_send(sock, msg, scm); @@ -55,8 +66,18 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg, #ifdef CONFIG_SECURITY_NETWORK static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) { - if (test_bit(SOCK_PASSSEC, &sock->flags) && scm->secdata != NULL) - put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, scm->seclen, scm->secdata); + char *secdata; + u32 seclen; + int err; + + if (test_bit(SOCK_PASSSEC, &sock->flags)) { + err = security_secid_to_secctx(scm->secid, &secdata, &seclen); + + if (!err) { + put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata); + security_release_secctx(secdata, seclen); + } + } } #else static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) -- cgit v1.2.3