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[PATCH] SELinux: extend task_kill hook to handle signals sent by AIO …
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…completion

This patch extends the security_task_kill hook to handle signals sent by AIO
completion.  In this case, the secid of the task responsible for the signal
needs to be obtained and saved earlier, so a security_task_getsecid() hook is
added, and then this saved value is passed subsequently to the extended
task_kill hook for use in checking.

Signed-off-by: David Quigley <dpquigl@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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David Quigley authored and Linus Torvalds committed Jun 30, 2006
1 parent ed11d9e commit f9008e4
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Showing 3 changed files with 40 additions and 9 deletions.
23 changes: 19 additions & 4 deletions include/linux/security.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -567,6 +567,9 @@ struct swap_info_struct;
* @p.
* @p contains the task_struct for the process.
* Return 0 if permission is granted.
* @task_getsecid:
* Retrieve the security identifier of the process @p.
* @p contains the task_struct for the process and place is into @secid.
* @task_setgroups:
* Check permission before setting the supplementary group set of the
* current process.
Expand Down Expand Up @@ -615,6 +618,7 @@ struct swap_info_struct;
* @p contains the task_struct for process.
* @info contains the signal information.
* @sig contains the signal value.
* @secid contains the sid of the process where the signal originated
* Return 0 if permission is granted.
* @task_wait:
* Check permission before allowing a process to reap a child process @p
Expand Down Expand Up @@ -1219,6 +1223,7 @@ struct security_operations {
int (*task_setpgid) (struct task_struct * p, pid_t pgid);
int (*task_getpgid) (struct task_struct * p);
int (*task_getsid) (struct task_struct * p);
void (*task_getsecid) (struct task_struct * p, u32 * secid);
int (*task_setgroups) (struct group_info *group_info);
int (*task_setnice) (struct task_struct * p, int nice);
int (*task_setioprio) (struct task_struct * p, int ioprio);
Expand All @@ -1228,7 +1233,7 @@ struct security_operations {
int (*task_getscheduler) (struct task_struct * p);
int (*task_movememory) (struct task_struct * p);
int (*task_kill) (struct task_struct * p,
struct siginfo * info, int sig);
struct siginfo * info, int sig, u32 secid);
int (*task_wait) (struct task_struct * p);
int (*task_prctl) (int option, unsigned long arg2,
unsigned long arg3, unsigned long arg4,
Expand Down Expand Up @@ -1839,6 +1844,11 @@ static inline int security_task_getsid (struct task_struct *p)
return security_ops->task_getsid (p);
}

static inline void security_task_getsecid (struct task_struct *p, u32 *secid)
{
security_ops->task_getsecid (p, secid);
}

static inline int security_task_setgroups (struct group_info *group_info)
{
return security_ops->task_setgroups (group_info);
Expand Down Expand Up @@ -1878,9 +1888,10 @@ static inline int security_task_movememory (struct task_struct *p)
}

static inline int security_task_kill (struct task_struct *p,
struct siginfo *info, int sig)
struct siginfo *info, int sig,
u32 secid)
{
return security_ops->task_kill (p, info, sig);
return security_ops->task_kill (p, info, sig, secid);
}

static inline int security_task_wait (struct task_struct *p)
Expand Down Expand Up @@ -2491,6 +2502,9 @@ static inline int security_task_getsid (struct task_struct *p)
return 0;
}

static inline void security_task_getsecid (struct task_struct *p, u32 *secid)
{ }

static inline int security_task_setgroups (struct group_info *group_info)
{
return 0;
Expand Down Expand Up @@ -2530,7 +2544,8 @@ static inline int security_task_movememory (struct task_struct *p)
}

static inline int security_task_kill (struct task_struct *p,
struct siginfo *info, int sig)
struct siginfo *info, int sig,
u32 secid)
{
return 0;
}
Expand Down
6 changes: 5 additions & 1 deletion security/dummy.c
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Original file line number Diff line number Diff line change
Expand Up @@ -506,6 +506,9 @@ static int dummy_task_getsid (struct task_struct *p)
return 0;
}

static void dummy_task_getsecid (struct task_struct *p, u32 *secid)
{ }

static int dummy_task_setgroups (struct group_info *group_info)
{
return 0;
Expand Down Expand Up @@ -548,7 +551,7 @@ static int dummy_task_wait (struct task_struct *p)
}

static int dummy_task_kill (struct task_struct *p, struct siginfo *info,
int sig)
int sig, u32 secid)
{
return 0;
}
Expand Down Expand Up @@ -981,6 +984,7 @@ void security_fixup_ops (struct security_operations *ops)
set_to_dummy_if_null(ops, task_setpgid);
set_to_dummy_if_null(ops, task_getpgid);
set_to_dummy_if_null(ops, task_getsid);
set_to_dummy_if_null(ops, task_getsecid);
set_to_dummy_if_null(ops, task_setgroups);
set_to_dummy_if_null(ops, task_setnice);
set_to_dummy_if_null(ops, task_setioprio);
Expand Down
20 changes: 16 additions & 4 deletions security/selinux/hooks.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2644,6 +2644,11 @@ static int selinux_task_getsid(struct task_struct *p)
return task_has_perm(current, p, PROCESS__GETSESSION);
}

static void selinux_task_getsecid(struct task_struct *p, u32 *secid)
{
selinux_get_task_sid(p, secid);
}

static int selinux_task_setgroups(struct group_info *group_info)
{
/* See the comment for setuid above. */
Expand Down Expand Up @@ -2700,12 +2705,14 @@ static int selinux_task_movememory(struct task_struct *p)
return task_has_perm(current, p, PROCESS__SETSCHED);
}

static int selinux_task_kill(struct task_struct *p, struct siginfo *info, int sig)
static int selinux_task_kill(struct task_struct *p, struct siginfo *info,
int sig, u32 secid)
{
u32 perm;
int rc;
struct task_security_struct *tsec;

rc = secondary_ops->task_kill(p, info, sig);
rc = secondary_ops->task_kill(p, info, sig, secid);
if (rc)
return rc;

Expand All @@ -2716,8 +2723,12 @@ static int selinux_task_kill(struct task_struct *p, struct siginfo *info, int si
perm = PROCESS__SIGNULL; /* null signal; existence test */
else
perm = signal_to_av(sig);

return task_has_perm(current, p, perm);
tsec = p->security;
if (secid)
rc = avc_has_perm(secid, tsec->sid, SECCLASS_PROCESS, perm, NULL);
else
rc = task_has_perm(current, p, perm);
return rc;
}

static int selinux_task_prctl(int option,
Expand Down Expand Up @@ -4434,6 +4445,7 @@ static struct security_operations selinux_ops = {
.task_setpgid = selinux_task_setpgid,
.task_getpgid = selinux_task_getpgid,
.task_getsid = selinux_task_getsid,
.task_getsecid = selinux_task_getsecid,
.task_setgroups = selinux_task_setgroups,
.task_setnice = selinux_task_setnice,
.task_setioprio = selinux_task_setioprio,
Expand Down

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