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authorDavid Howells <dhowells@redhat.com>2008-11-14 10:39:19 +1100
committerJames Morris <jmorris@namei.org>2008-11-14 10:39:19 +1100
commitc69e8d9c01db2adc503464993c358901c9af9de4 (patch)
treebed94aaa9aeb7a7834d1c880f72b62a11a752c78 /kernel/auditsc.c
parent86a264abe542cfececb4df129bc45a0338d8cdb9 (diff)
downloadlinux-c69e8d9c01db2adc503464993c358901c9af9de4.tar.bz2
CRED: Use RCU to access another task's creds and to release a task's own creds
Use RCU to access another task's creds and to release a task's own creds. This means that it will be possible for the credentials of a task to be replaced without another task (a) requiring a full lock to read them, and (b) seeing deallocated memory. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'kernel/auditsc.c')
-rw-r--r--kernel/auditsc.c33
1 files changed, 19 insertions, 14 deletions
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 2febf5165fad..ae8ef88ade3f 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -447,7 +447,7 @@ static int audit_filter_rules(struct task_struct *tsk,
struct audit_names *name,
enum audit_state *state)
{
- struct cred *cred = tsk->cred;
+ const struct cred *cred = get_task_cred(tsk);
int i, j, need_sid = 1;
u32 sid;
@@ -642,8 +642,10 @@ static int audit_filter_rules(struct task_struct *tsk,
break;
}
- if (!result)
+ if (!result) {
+ put_cred(cred);
return 0;
+ }
}
if (rule->filterkey && ctx)
ctx->filterkey = kstrdup(rule->filterkey, GFP_ATOMIC);
@@ -651,6 +653,7 @@ static int audit_filter_rules(struct task_struct *tsk,
case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
}
+ put_cred(cred);
return 1;
}
@@ -1229,7 +1232,7 @@ static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
static void audit_log_exit(struct audit_context *context, struct task_struct *tsk)
{
- struct cred *cred = tsk->cred;
+ const struct cred *cred;
int i, call_panic = 0;
struct audit_buffer *ab;
struct audit_aux_data *aux;
@@ -1239,13 +1242,14 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
context->pid = tsk->pid;
if (!context->ppid)
context->ppid = sys_getppid();
- context->uid = cred->uid;
- context->gid = cred->gid;
- context->euid = cred->euid;
- context->suid = cred->suid;
+ cred = current_cred();
+ context->uid = cred->uid;
+ context->gid = cred->gid;
+ context->euid = cred->euid;
+ context->suid = cred->suid;
context->fsuid = cred->fsuid;
- context->egid = cred->egid;
- context->sgid = cred->sgid;
+ context->egid = cred->egid;
+ context->sgid = cred->sgid;
context->fsgid = cred->fsgid;
context->personality = tsk->personality;
@@ -2088,7 +2092,7 @@ int audit_set_loginuid(struct task_struct *task, uid_t loginuid)
audit_log_format(ab, "login pid=%d uid=%u "
"old auid=%u new auid=%u"
" old ses=%u new ses=%u",
- task->pid, task->cred->uid,
+ task->pid, task_uid(task),
task->loginuid, loginuid,
task->sessionid, sessionid);
audit_log_end(ab);
@@ -2471,7 +2475,7 @@ void __audit_ptrace(struct task_struct *t)
context->target_pid = t->pid;
context->target_auid = audit_get_loginuid(t);
- context->target_uid = t->cred->uid;
+ context->target_uid = task_uid(t);
context->target_sessionid = audit_get_sessionid(t);
security_task_getsecid(t, &context->target_sid);
memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
@@ -2490,6 +2494,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
struct audit_aux_data_pids *axp;
struct task_struct *tsk = current;
struct audit_context *ctx = tsk->audit_context;
+ uid_t uid = current_uid(), t_uid = task_uid(t);
if (audit_pid && t->tgid == audit_pid) {
if (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1 || sig == SIGUSR2) {
@@ -2497,7 +2502,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
if (tsk->loginuid != -1)
audit_sig_uid = tsk->loginuid;
else
- audit_sig_uid = tsk->cred->uid;
+ audit_sig_uid = uid;
security_task_getsecid(tsk, &audit_sig_sid);
}
if (!audit_signals || audit_dummy_context())
@@ -2509,7 +2514,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
if (!ctx->target_pid) {
ctx->target_pid = t->tgid;
ctx->target_auid = audit_get_loginuid(t);
- ctx->target_uid = t->cred->uid;
+ ctx->target_uid = t_uid;
ctx->target_sessionid = audit_get_sessionid(t);
security_task_getsecid(t, &ctx->target_sid);
memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
@@ -2530,7 +2535,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
axp->target_pid[axp->pid_count] = t->tgid;
axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
- axp->target_uid[axp->pid_count] = t->cred->uid;
+ axp->target_uid[axp->pid_count] = t_uid;
axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
security_task_getsecid(t, &axp->target_sid[axp->pid_count]);
memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);