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 <darwish.07@gmail.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ahmed S. Darwish 2008-03-19 17:00:51 -07:00 committed by Linus Torvalds
parent 4ebf89845b
commit 1d252fb870
1 changed files with 6 additions and 3 deletions

View File

@ -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);
}