From 1d252fb870aa9cd227c4beb1a226ecd434f57f28 Mon Sep 17 00:00:00 2001 From: "Ahmed S. Darwish" Date: Wed, 19 Mar 2008 17:00:51 -0700 Subject: [PATCH] smack: do not dereference NULL ipc object In the SYSV ipc msgctl(),semctl(),shmctl() family, if the user passed *_INFO as the desired operation, no specific object is meant to be controlled and only system-wide information is returned. This leads to a NULL IPC object in the LSM hooks if the _INFO flag is given. Avoid dereferencing this NULL pointer in Smack ipc *ctl() methods. Signed-off-by: Ahmed S. Darwish Acked-by: Casey Schaufler Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- security/smack/smack_lsm.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 0241fd359675..38d707593b31 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1508,7 +1508,7 @@ static int smack_shm_associate(struct shmid_kernel *shp, int shmflg) */ static int smack_shm_shmctl(struct shmid_kernel *shp, int cmd) { - char *ssp = smack_of_shm(shp); + char *ssp; int may; switch (cmd) { @@ -1532,6 +1532,7 @@ static int smack_shm_shmctl(struct shmid_kernel *shp, int cmd) return -EINVAL; } + ssp = smack_of_shm(shp); return smk_curacc(ssp, may); } @@ -1616,7 +1617,7 @@ static int smack_sem_associate(struct sem_array *sma, int semflg) */ static int smack_sem_semctl(struct sem_array *sma, int cmd) { - char *ssp = smack_of_sem(sma); + char *ssp; int may; switch (cmd) { @@ -1645,6 +1646,7 @@ static int smack_sem_semctl(struct sem_array *sma, int cmd) return -EINVAL; } + ssp = smack_of_sem(sma); return smk_curacc(ssp, may); } @@ -1730,7 +1732,7 @@ static int smack_msg_queue_associate(struct msg_queue *msq, int msqflg) */ static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd) { - char *msp = smack_of_msq(msq); + char *msp; int may; switch (cmd) { @@ -1752,6 +1754,7 @@ static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd) return -EINVAL; } + msp = smack_of_msq(msq); return smk_curacc(msp, may); }