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Subject[PATCH 11/24] CRED: Use RCU to access another task's creds and to release a task's own creds [ver #7]
Date
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>
---
drivers/connector/cn_proc.c | 16 +++++++----
fs/binfmt_elf.c | 8 ++++-
fs/binfmt_elf_fdpic.c | 8 ++++-
fs/fcntl.c | 15 +++++++---
fs/fuse/dir.c | 23 ++++++++++-----
fs/ioprio.c | 14 +++++++--
fs/proc/array.c | 32 ++++++++++++++-------
fs/proc/base.c | 32 ++++++++++++++++-----
include/linux/cred.h | 3 +-
kernel/auditsc.c | 33 ++++++++++++----------
kernel/cgroup.c | 16 +++++------
kernel/exit.c | 14 ++++++---
kernel/futex.c | 22 +++++++++-----
kernel/futex_compat.c | 7 +++--
kernel/ptrace.c | 22 +++++++++-----
kernel/sched.c | 31 ++++++++++++++------
kernel/signal.c | 49 ++++++++++++++++++++------------
kernel/sys.c | 11 +++++--
kernel/tsacct.c | 6 +++-
mm/mempolicy.c | 8 +++--
mm/migrate.c | 8 +++--
mm/oom_kill.c | 6 ++--
security/commoncap.c | 64 ++++++++++++++++++++++++++----------------
security/keys/permission.c | 10 ++++---
security/keys/process_keys.c | 24 +++++++++-------
security/selinux/selinuxfs.c | 13 ++++++---
security/smack/smack_lsm.c | 32 +++++++++++----------
27 files changed, 335 insertions(+), 192 deletions(-)

diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index 354c1ff..c5afc98 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -106,6 +106,7 @@ void proc_id_connector(struct task_struct *task, int which_id)
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE];
struct timespec ts;
+ const struct cred *cred;

if (atomic_read(&proc_event_num_listeners) < 1)
return;
@@ -115,14 +116,19 @@ void proc_id_connector(struct task_struct *task, int which_id)
ev->what = which_id;
ev->event_data.id.process_pid = task->pid;
ev->event_data.id.process_tgid = task->tgid;
+ rcu_read_lock();
+ cred = __task_cred(task);
if (which_id == PROC_EVENT_UID) {
- ev->event_data.id.r.ruid = task->cred->uid;
- ev->event_data.id.e.euid = task->cred->euid;
+ ev->event_data.id.r.ruid = cred->uid;
+ ev->event_data.id.e.euid = cred->euid;
} else if (which_id == PROC_EVENT_GID) {
- ev->event_data.id.r.rgid = task->cred->gid;
- ev->event_data.id.e.egid = task->cred->egid;
- } else
+ ev->event_data.id.r.rgid = cred->gid;
+ ev->event_data.id.e.egid = cred->egid;
+ } else {
+ rcu_read_unlock();
return;
+ }
+ rcu_read_unlock();
get_seq(&msg->seq, &ev->cpu);
ktime_get_ts(&ts); /* get high res monotonic timestamp */
put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 8692d4a..8761e97 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1358,6 +1358,7 @@ static void fill_prstatus(struct elf_prstatus *prstatus,
static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
struct mm_struct *mm)
{
+ const struct cred *cred;
unsigned int i, len;

/* first copy the parameters from user space */
@@ -1385,8 +1386,11 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
psinfo->pr_zomb = psinfo->pr_sname == 'Z';
psinfo->pr_nice = task_nice(p);
psinfo->pr_flag = p->flags;
- SET_UID(psinfo->pr_uid, p->cred->uid);
- SET_GID(psinfo->pr_gid, p->cred->gid);
+ rcu_read_lock();
+ cred = __task_cred(p);
+ SET_UID(psinfo->pr_uid, cred->uid);
+ SET_GID(psinfo->pr_gid, cred->gid);
+ rcu_read_unlock();
strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));

return 0;
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 6232e55..5625b23 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1380,6 +1380,7 @@ static void fill_prstatus(struct elf_prstatus *prstatus,
static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
struct mm_struct *mm)
{
+ const struct cred *cred;
unsigned int i, len;

/* first copy the parameters from user space */
@@ -1407,8 +1408,11 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
psinfo->pr_zomb = psinfo->pr_sname == 'Z';
psinfo->pr_nice = task_nice(p);
psinfo->pr_flag = p->flags;
- SET_UID(psinfo->pr_uid, p->cred->uid);
- SET_GID(psinfo->pr_gid, p->cred->gid);
+ rcu_read_lock();
+ cred = __task_cred(p);
+ SET_UID(psinfo->pr_uid, cred->uid);
+ SET_GID(psinfo->pr_gid, cred->gid);
+ rcu_read_unlock();
strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));

return 0;
diff --git a/fs/fcntl.c b/fs/fcntl.c
index c594cc0..87c39f1 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -401,10 +401,17 @@ static const long band_table[NSIGPOLL] = {
static inline int sigio_perm(struct task_struct *p,
struct fown_struct *fown, int sig)
{
- return (((fown->euid == 0) ||
- (fown->euid == p->cred->suid) || (fown->euid == p->cred->uid) ||
- (fown->uid == p->cred->suid) || (fown->uid == p->cred->uid)) &&
- !security_file_send_sigiotask(p, fown, sig));
+ const struct cred *cred;
+ int ret;
+
+ rcu_read_lock();
+ cred = __task_cred(p);
+ ret = ((fown->euid == 0 ||
+ fown->euid == cred->suid || fown->euid == cred->uid ||
+ fown->uid == cred->suid || fown->uid == cred->uid) &&
+ !security_file_send_sigiotask(p, fown, sig));
+ rcu_read_unlock();
+ return ret;
}

static void send_sigio_to_task(struct task_struct *p,
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index e97a989..95bc22b 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -869,18 +869,25 @@ int fuse_update_attributes(struct inode *inode, struct kstat *stat,
*/
int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task)
{
+ const struct cred *cred;
+ int ret;
+
if (fc->flags & FUSE_ALLOW_OTHER)
return 1;

- if (task->cred->euid == fc->user_id &&
- task->cred->suid == fc->user_id &&
- task->cred->uid == fc->user_id &&
- task->cred->egid == fc->group_id &&
- task->cred->sgid == fc->group_id &&
- task->cred->gid == fc->group_id)
- return 1;
+ rcu_read_lock();
+ ret = 0;
+ cred = __task_cred(task);
+ if (cred->euid == fc->user_id &&
+ cred->suid == fc->user_id &&
+ cred->uid == fc->user_id &&
+ cred->egid == fc->group_id &&
+ cred->sgid == fc->group_id &&
+ cred->gid == fc->group_id)
+ ret = 1;
+ rcu_read_unlock();

- return 0;
+ return ret;
}

static int fuse_access(struct inode *inode, int mask)
diff --git a/fs/ioprio.c b/fs/ioprio.c
index 6d96eac..f716f8d 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -31,10 +31,16 @@ static int set_task_ioprio(struct task_struct *task, int ioprio)
{
int err;
struct io_context *ioc;
+ const struct cred *cred = current_cred(), *tcred;

- if (task->cred->uid != current_euid() &&
- task->cred->uid != current_uid() && !capable(CAP_SYS_NICE))
+ rcu_read_lock();
+ tcred = __task_cred(task);
+ if (tcred->uid != cred->euid &&
+ tcred->uid != cred->uid && !capable(CAP_SYS_NICE)) {
+ rcu_read_unlock();
return -EPERM;
+ }
+ rcu_read_unlock();

err = security_task_setioprio(task, ioprio);
if (err)
@@ -131,7 +137,7 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
break;

do_each_thread(g, p) {
- if (p->cred->uid != who)
+ if (__task_cred(p)->uid != who)
continue;
ret = set_task_ioprio(p, ioprio);
if (ret)
@@ -224,7 +230,7 @@ asmlinkage long sys_ioprio_get(int which, int who)
break;

do_each_thread(g, p) {
- if (p->cred->uid != user->uid)
+ if (__task_cred(p)->uid != user->uid)
continue;
tmpio = get_task_ioprio(p);
if (tmpio < 0)
diff --git a/fs/proc/array.c b/fs/proc/array.c
index af0962b..13944a3 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -164,6 +164,7 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
struct group_info *group_info;
int g;
struct fdtable *fdt = NULL;
+ const struct cred *cred;
pid_t ppid, tpid;

rcu_read_lock();
@@ -175,6 +176,7 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
if (tracer)
tpid = task_pid_nr_ns(tracer, ns);
}
+ cred = get_cred((struct cred *) __task_cred(p));
seq_printf(m,
"State:\t%s\n"
"Tgid:\t%d\n"
@@ -187,8 +189,8 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
task_tgid_nr_ns(p, ns),
pid_nr_ns(pid, ns),
ppid, tpid,
- p->cred->uid, p->cred->euid, p->cred->suid, p->cred->fsuid,
- p->cred->gid, p->cred->egid, p->cred->sgid, p->cred->fsgid);
+ cred->uid, cred->euid, cred->suid, cred->fsuid,
+ cred->gid, cred->egid, cred->sgid, cred->fsgid);

task_lock(p);
if (p->files)
@@ -199,13 +201,12 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
fdt ? fdt->max_fds : 0);
rcu_read_unlock();

- group_info = p->cred->group_info;
- get_group_info(group_info);
+ group_info = cred->group_info;
task_unlock(p);

for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
seq_printf(m, "%d ", GROUP_AT(group_info, g));
- put_group_info(group_info);
+ put_cred(cred);

seq_printf(m, "\n");
}
@@ -268,7 +269,7 @@ static inline void task_sig(struct seq_file *m, struct task_struct *p)
blocked = p->blocked;
collect_sigign_sigcatch(p, &ignored, &caught);
num_threads = atomic_read(&p->signal->count);
- qsize = atomic_read(&p->cred->user->sigpending);
+ qsize = atomic_read(&__task_cred(p)->user->sigpending);
qlim = p->signal->rlim[RLIMIT_SIGPENDING].rlim_cur;
unlock_task_sighand(p, &flags);
}
@@ -300,12 +301,21 @@ static void render_cap_t(struct seq_file *m, const char *header,

static inline void task_cap(struct seq_file *m, struct task_struct *p)
{
- struct cred *cred = p->cred;
+ const struct cred *cred;
+ kernel_cap_t cap_inheritable, cap_permitted, cap_effective, cap_bset;

- render_cap_t(m, "CapInh:\t", &cred->cap_inheritable);
- render_cap_t(m, "CapPrm:\t", &cred->cap_permitted);
- render_cap_t(m, "CapEff:\t", &cred->cap_effective);
- render_cap_t(m, "CapBnd:\t", &cred->cap_bset);
+ rcu_read_lock();
+ cred = __task_cred(p);
+ cap_inheritable = cred->cap_inheritable;
+ cap_permitted = cred->cap_permitted;
+ cap_effective = cred->cap_effective;
+ cap_bset = cred->cap_bset;
+ rcu_read_unlock();
+
+ render_cap_t(m, "CapInh:\t", &cap_inheritable);
+ render_cap_t(m, "CapPrm:\t", &cap_permitted);
+ render_cap_t(m, "CapEff:\t", &cap_effective);
+ render_cap_t(m, "CapBnd:\t", &cap_bset);
}

static inline void task_context_switch_counts(struct seq_file *m,
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 96fb315..74db376 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1414,6 +1414,7 @@ static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_st
{
struct inode * inode;
struct proc_inode *ei;
+ const struct cred *cred;

/* We need a new inode */

@@ -1436,8 +1437,11 @@ static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_st
inode->i_uid = 0;
inode->i_gid = 0;
if (task_dumpable(task)) {
- inode->i_uid = task->cred->euid;
- inode->i_gid = task->cred->egid;
+ rcu_read_lock();
+ cred = __task_cred(task);
+ inode->i_uid = cred->euid;
+ inode->i_gid = cred->egid;
+ rcu_read_unlock();
}
security_task_to_inode(task, inode);

@@ -1453,6 +1457,8 @@ static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat
{
struct inode *inode = dentry->d_inode;
struct task_struct *task;
+ const struct cred *cred;
+
generic_fillattr(inode, stat);

rcu_read_lock();
@@ -1462,8 +1468,9 @@ static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat
if (task) {
if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
task_dumpable(task)) {
- stat->uid = task->cred->euid;
- stat->gid = task->cred->egid;
+ cred = __task_cred(task);
+ stat->uid = cred->euid;
+ stat->gid = cred->egid;
}
}
rcu_read_unlock();
@@ -1491,11 +1498,16 @@ static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
{
struct inode *inode = dentry->d_inode;
struct task_struct *task = get_proc_task(inode);
+ const struct cred *cred;
+
if (task) {
if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
task_dumpable(task)) {
- inode->i_uid = task->cred->euid;
- inode->i_gid = task->cred->egid;
+ rcu_read_lock();
+ cred = __task_cred(task);
+ inode->i_uid = cred->euid;
+ inode->i_gid = cred->egid;
+ rcu_read_unlock();
} else {
inode->i_uid = 0;
inode->i_gid = 0;
@@ -1657,6 +1669,7 @@ static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
struct task_struct *task = get_proc_task(inode);
int fd = proc_fd(inode);
struct files_struct *files;
+ const struct cred *cred;

if (task) {
files = get_files_struct(task);
@@ -1666,8 +1679,11 @@ static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
rcu_read_unlock();
put_files_struct(files);
if (task_dumpable(task)) {
- inode->i_uid = task->cred->euid;
- inode->i_gid = task->cred->egid;
+ rcu_read_lock();
+ cred = __task_cred(task);
+ inode->i_uid = cred->euid;
+ inode->i_gid = cred->egid;
+ rcu_read_unlock();
} else {
inode->i_uid = 0;
inode->i_gid = 0;
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 45e954d..5c4e098 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -147,8 +147,9 @@ static inline struct cred *get_cred(struct cred *cred)
* Release a reference to a set of credentials, deleting them when the last ref
* is released.
*/
-static inline void put_cred(struct cred *cred)
+static inline void put_cred(const struct cred *_cred)
{
+ struct cred *cred = (struct cred *) _cred;
if (atomic_dec_and_test(&(cred)->usage))
__put_cred(cred);
}
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 9e817df..58c3854 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -413,7 +413,7 @@ 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;

@@ -608,8 +608,10 @@ 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);
@@ -617,6 +619,7 @@ 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;
}

@@ -1166,7 +1169,7 @@ static void audit_log_execve_info(struct audit_context *context,

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;
@@ -1176,13 +1179,14 @@ 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;

@@ -1973,7 +1977,7 @@ 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);
@@ -2356,7 +2360,7 @@ 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);
@@ -2375,6 +2379,7 @@ 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) {
@@ -2382,7 +2387,7 @@ 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())
@@ -2394,7 +2399,7 @@ 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);
@@ -2415,7 +2420,7 @@ 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);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 5658dc3..3569fef 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1276,7 +1276,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
{
struct task_struct *tsk;
- uid_t euid;
+ const struct cred *cred = current_cred(), *tcred;
int ret;

if (pid) {
@@ -1286,16 +1286,16 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
rcu_read_unlock();
return -ESRCH;
}
- get_task_struct(tsk);
- rcu_read_unlock();

- euid = current_euid();
- if (euid &&
- euid != tsk->cred->uid &&
- euid != tsk->cred->suid) {
- put_task_struct(tsk);
+ tcred = __task_cred(tsk);
+ if (cred->euid &&
+ cred->euid != tcred->uid &&
+ cred->euid != tcred->suid) {
+ rcu_read_unlock();
return -EACCES;
}
+ get_task_struct(tsk);
+ rcu_read_unlock();
} else {
tsk = current;
get_task_struct(tsk);
diff --git a/kernel/exit.c b/kernel/exit.c
index 5ba3db3..9bce79b 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -159,7 +159,10 @@ void release_task(struct task_struct * p)
int zap_leader;
repeat:
tracehook_prepare_release_task(p);
- atomic_dec(&p->cred->user->processes);
+ /* don't need to get the RCU readlock here - the process is dead and
+ * can't be modifying its own credentials */
+ atomic_dec(&__task_cred(p)->user->processes);
+
proc_flush_task(p);
write_lock_irq(&tasklist_lock);
tracehook_finish_release_task(p);
@@ -1267,12 +1270,12 @@ static int wait_task_zombie(struct task_struct *p, int options,
unsigned long state;
int retval, status, traced;
pid_t pid = task_pid_vnr(p);
+ uid_t uid = __task_cred(p)->uid;

if (!likely(options & WEXITED))
return 0;

if (unlikely(options & WNOWAIT)) {
- uid_t uid = p->cred->uid;
int exit_code = p->exit_code;
int why, status;

@@ -1389,7 +1392,7 @@ static int wait_task_zombie(struct task_struct *p, int options,
if (!retval && infop)
retval = put_user(pid, &infop->si_pid);
if (!retval && infop)
- retval = put_user(p->cred->uid, &infop->si_uid);
+ retval = put_user(uid, &infop->si_uid);
if (!retval)
retval = pid;

@@ -1454,7 +1457,8 @@ static int wait_task_stopped(int ptrace, struct task_struct *p,
if (!unlikely(options & WNOWAIT))
p->exit_code = 0;

- uid = p->cred->uid;
+ /* don't need the RCU readlock here as we're holding a spinlock */
+ uid = __task_cred(p)->uid;
unlock_sig:
spin_unlock_irq(&p->sighand->siglock);
if (!exit_code)
@@ -1528,10 +1532,10 @@ static int wait_task_continued(struct task_struct *p, int options,
}
if (!unlikely(options & WNOWAIT))
p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
+ uid = __task_cred(p)->uid;
spin_unlock_irq(&p->sighand->siglock);

pid = task_pid_vnr(p);
- uid = p->cred->uid;
get_task_struct(p);
read_unlock(&tasklist_lock);

diff --git a/kernel/futex.c b/kernel/futex.c
index 3f594ac..063795e 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -439,15 +439,20 @@ static void free_pi_state(struct futex_pi_state *pi_state)
static struct task_struct * futex_find_get_task(pid_t pid)
{
struct task_struct *p;
- uid_t euid = current_euid();
+ const struct cred *cred = current_cred(), *pcred;

rcu_read_lock();
p = find_task_by_vpid(pid);
- if (!p || (euid != p->cred->euid &&
- euid != p->cred->uid))
+ if (!p) {
p = ERR_PTR(-ESRCH);
- else
- get_task_struct(p);
+ } else {
+ pcred = __task_cred(p);
+ if (cred->euid != pcred->euid &&
+ cred->euid != pcred->uid)
+ p = ERR_PTR(-ESRCH);
+ else
+ get_task_struct(p);
+ }

rcu_read_unlock();

@@ -1828,7 +1833,7 @@ sys_get_robust_list(int pid, struct robust_list_head __user * __user *head_ptr,
{
struct robust_list_head __user *head;
unsigned long ret;
- uid_t euid = current_euid();
+ const struct cred *cred = current_cred(), *pcred;

if (!futex_cmpxchg_enabled)
return -ENOSYS;
@@ -1844,8 +1849,9 @@ sys_get_robust_list(int pid, struct robust_list_head __user * __user *head_ptr,
if (!p)
goto err_unlock;
ret = -EPERM;
- if (euid != p->cred->euid &&
- euid != p->cred->uid &&
+ pcred = __task_cred(p);
+ if (cred->euid != pcred->euid &&
+ cred->euid != pcred->uid &&
!capable(CAP_SYS_PTRACE))
goto err_unlock;
head = p->robust_list;
diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
index 2c3fd5e..d607a5b 100644
--- a/kernel/futex_compat.c
+++ b/kernel/futex_compat.c
@@ -135,7 +135,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
{
struct compat_robust_list_head __user *head;
unsigned long ret;
- uid_t euid = current_euid();
+ const struct cred *cred = current_cred(), *pcred;

if (!futex_cmpxchg_enabled)
return -ENOSYS;
@@ -151,8 +151,9 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
if (!p)
goto err_unlock;
ret = -EPERM;
- if (euid != p->cred->euid &&
- euid != p->cred->uid &&
+ pcred = __task_cred(p);
+ if (cred->euid != pcred->euid &&
+ cred->euid != pcred->uid &&
!capable(CAP_SYS_PTRACE))
goto err_unlock;
head = p->compat_robust_list;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index efa4556..ed65d9f 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -115,7 +115,7 @@ int ptrace_check_attach(struct task_struct *child, int kill)

int __ptrace_may_access(struct task_struct *task, unsigned int mode)
{
- struct cred *cred = current->cred, *tcred = task->cred;
+ const struct cred *cred = current_cred(), *tcred;

/* May we inspect the given task?
* This check is used both for attaching with ptrace
@@ -125,19 +125,23 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
* because setting up the necessary parent/child relationship
* or halting the specified task is impossible.
*/
- uid_t uid = cred->uid;
- gid_t gid = cred->gid;
int dumpable = 0;
/* Don't let security modules deny introspection */
if (task == current)
return 0;
- if ((uid != tcred->euid ||
- uid != tcred->suid ||
- uid != tcred->uid ||
- gid != tcred->egid ||
- gid != tcred->sgid ||
- gid != tcred->gid) && !capable(CAP_SYS_PTRACE))
+ rcu_read_lock();
+ tcred = __task_cred(task);
+ if ((cred->uid != tcred->euid ||
+ cred->uid != tcred->suid ||
+ cred->uid != tcred->uid ||
+ cred->gid != tcred->egid ||
+ cred->gid != tcred->sgid ||
+ cred->gid != tcred->gid) &&
+ !capable(CAP_SYS_PTRACE)) {
+ rcu_read_unlock();
return -EPERM;
+ }
+ rcu_read_unlock();
smp_rmb();
if (task->mm)
dumpable = get_dumpable(task->mm);
diff --git a/kernel/sched.c b/kernel/sched.c
index 152ea80..dd85fe0 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -339,7 +339,9 @@ static inline struct task_group *task_group(struct task_struct *p)
struct task_group *tg;

#ifdef CONFIG_USER_SCHED
- tg = p->cred->user->tg;
+ rcu_read_lock();
+ tg = __task_cred(p)->user->tg;
+ rcu_read_unlock();
#elif defined(CONFIG_CGROUP_SCHED)
tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
struct task_group, css);
@@ -4940,6 +4942,22 @@ __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
set_load_weight(p);
}

+/*
+ * check the target process has a UID that matches the current process's
+ */
+static bool check_same_owner(struct task_struct *p)
+{
+ const struct cred *cred = current_cred(), *pcred;
+ bool match;
+
+ rcu_read_lock();
+ pcred = __task_cred(p);
+ match = (cred->euid == pcred->euid ||
+ cred->euid == pcred->uid);
+ rcu_read_unlock();
+ return match;
+}
+
static int __sched_setscheduler(struct task_struct *p, int policy,
struct sched_param *param, bool user)
{
@@ -4947,7 +4965,6 @@ static int __sched_setscheduler(struct task_struct *p, int policy,
unsigned long flags;
const struct sched_class *prev_class = p->sched_class;
struct rq *rq;
- uid_t euid;

/* may grab non-irq protected spin_locks */
BUG_ON(in_interrupt());
@@ -5000,9 +5017,7 @@ recheck:
return -EPERM;

/* can't change other user's priorities */
- euid = current_euid();
- if (euid != p->cred->euid &&
- euid != p->cred->uid)
+ if (!check_same_owner(p))
return -EPERM;
}

@@ -5210,7 +5225,6 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
cpumask_t cpus_allowed;
cpumask_t new_mask = *in_mask;
struct task_struct *p;
- uid_t euid;
int retval;

get_online_cpus();
@@ -5231,11 +5245,8 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
get_task_struct(p);
read_unlock(&tasklist_lock);

- euid = current_euid();
retval = -EPERM;
- if (euid != p->cred->euid &&
- euid != p->cred->uid &&
- !capable(CAP_SYS_NICE))
+ if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
goto out_unlock;

retval = security_task_setscheduler(p, 0, NULL);
diff --git a/kernel/signal.c b/kernel/signal.c
index dfdbaaf..2632d94 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -176,6 +176,11 @@ int next_signal(struct sigpending *pending, sigset_t *mask)
return sig;
}

+/*
+ * allocate a new signal queue record
+ * - this may be called without locks if and only if t == current, otherwise an
+ * appopriate lock must be held to protect t's user_struct
+ */
static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
int override_rlimit)
{
@@ -183,11 +188,12 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
struct user_struct *user;

/*
- * In order to avoid problems with "switch_user()", we want to make
- * sure that the compiler doesn't re-load "t->user"
+ * We won't get problems with the target's UID changing under us
+ * because changing it requires RCU be used, and if t != current, the
+ * caller must be holding the RCU readlock (by way of a spinlock) and
+ * we use RCU protection here
*/
- user = t->cred->user;
- barrier();
+ user = __task_cred(t)->user;
atomic_inc(&user->sigpending);
if (override_rlimit ||
atomic_read(&user->sigpending) <=
@@ -561,12 +567,13 @@ static int rm_from_queue(unsigned long mask, struct sigpending *s)

/*
* Bad permissions for sending the signal
+ * - the caller must hold at least the RCU read lock
*/
static int check_kill_permission(int sig, struct siginfo *info,
struct task_struct *t)
{
+ const struct cred *cred = current_cred(), *tcred;
struct pid *sid;
- uid_t uid, euid;
int error;

if (!valid_signal(sig))
@@ -579,10 +586,11 @@ static int check_kill_permission(int sig, struct siginfo *info,
if (error)
return error;

- uid = current_uid();
- euid = current_euid();
- if ((euid ^ t->cred->suid) && (euid ^ t->cred->uid) &&
- (uid ^ t->cred->suid) && (uid ^ t->cred->uid) &&
+ tcred = __task_cred(t);
+ if ((cred->euid ^ tcred->suid) &&
+ (cred->euid ^ tcred->uid) &&
+ (cred->uid ^ tcred->suid) &&
+ (cred->uid ^ tcred->uid) &&
!capable(CAP_KILL)) {
switch (sig) {
case SIGCONT:
@@ -1008,6 +1016,10 @@ struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long
return sighand;
}

+/*
+ * send signal info to all the members of a group
+ * - the caller must hold the RCU read lock at least
+ */
int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
unsigned long flags;
@@ -1029,8 +1041,8 @@ int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
/*
* __kill_pgrp_info() sends a signal to a process group: this is what the tty
* control characters do (^C, ^Z etc)
+ * - the caller must hold at least a readlock on tasklist_lock
*/
-
int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
{
struct task_struct *p = NULL;
@@ -1086,6 +1098,7 @@ int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
{
int ret = -EINVAL;
struct task_struct *p;
+ const struct cred *pcred;

if (!valid_signal(sig))
return ret;
@@ -1096,9 +1109,11 @@ int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
ret = -ESRCH;
goto out_unlock;
}
- if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
- && (euid != p->cred->suid) && (euid != p->cred->uid)
- && (uid != p->cred->suid) && (uid != p->cred->uid)) {
+ pcred = __task_cred(p);
+ if ((info == SEND_SIG_NOINFO ||
+ (!is_si_special(info) && SI_FROMUSER(info))) &&
+ euid != pcred->suid && euid != pcred->uid &&
+ uid != pcred->suid && uid != pcred->uid) {
ret = -EPERM;
goto out_unlock;
}
@@ -1365,10 +1380,9 @@ int do_notify_parent(struct task_struct *tsk, int sig)
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
+ info.si_uid = __task_cred(tsk)->uid;
rcu_read_unlock();

- info.si_uid = tsk->cred->uid;
-
info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime,
tsk->signal->utime));
info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime,
@@ -1437,10 +1451,9 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
+ info.si_uid = __task_cred(tsk)->uid;
rcu_read_unlock();

- info.si_uid = tsk->cred->uid;
-
info.si_utime = cputime_to_clock_t(tsk->utime);
info.si_stime = cputime_to_clock_t(tsk->stime);

@@ -1707,7 +1720,7 @@ static int ptrace_signal(int signr, siginfo_t *info,
info->si_errno = 0;
info->si_code = SI_USER;
info->si_pid = task_pid_vnr(current->parent);
- info->si_uid = current->parent->cred->uid;
+ info->si_uid = task_uid(current->parent);
}

/* If the (new) signal is now blocked, requeue it. */
diff --git a/kernel/sys.c b/kernel/sys.c
index e2a16eb..4c4ac7a 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -112,14 +112,17 @@ EXPORT_SYMBOL(cad_pid);

void (*pm_power_off_prepare)(void);

+/*
+ * set the priority of a task
+ * - the caller must hold the RCU read lock
+ */
static int set_one_prio(struct task_struct *p, int niceval, int error)
{
- uid_t euid = current_euid();
+ const struct cred *cred = current_cred(), *pcred = __task_cred(p);
int no_nice;

- if (p->cred->uid != euid &&
- p->cred->euid != euid &&
- !capable(CAP_SYS_NICE)) {
+ if (pcred->uid != cred->euid &&
+ pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
error = -EPERM;
goto out;
}
diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 6d1ed07..2dc06ab 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -27,6 +27,7 @@
*/
void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
{
+ const struct cred *tcred;
struct timespec uptime, ts;
u64 ac_etime;

@@ -53,10 +54,11 @@ void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
stats->ac_flag |= AXSIG;
stats->ac_nice = task_nice(tsk);
stats->ac_sched = tsk->policy;
- stats->ac_uid = tsk->cred->uid;
- stats->ac_gid = tsk->cred->gid;
stats->ac_pid = tsk->pid;
rcu_read_lock();
+ tcred = __task_cred(tsk);
+ stats->ac_uid = tcred->uid;
+ stats->ac_gid = tcred->gid;
stats->ac_ppid = pid_alive(tsk) ?
rcu_dereference(tsk->real_parent)->tgid : 0;
rcu_read_unlock();
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 4374a83..488d4f6 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1106,7 +1106,7 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
const unsigned long __user *old_nodes,
const unsigned long __user *new_nodes)
{
- struct cred *cred, *tcred;
+ const struct cred *cred = current_cred(), *tcred;
struct mm_struct *mm;
struct task_struct *task;
nodemask_t old;
@@ -1141,14 +1141,16 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
* capabilities, superuser privileges or the same
* userid as the target process.
*/
- cred = current->cred;
- tcred = task->cred;
+ rcu_read_lock();
+ tcred = __task_cred(task);
if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
cred->uid != tcred->suid && cred->uid != tcred->uid &&
!capable(CAP_SYS_NICE)) {
+ rcu_read_unlock();
err = -EPERM;
goto out;
}
+ rcu_read_unlock();

task_nodes = cpuset_mems_allowed(task);
/* Is the user allowed to access the target nodes? */
diff --git a/mm/migrate.c b/mm/migrate.c
index 78af7fd..32b352d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -984,7 +984,7 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
const int __user *nodes,
int __user *status, int flags)
{
- struct cred *cred, *tcred;
+ const struct cred *cred = current_cred(), *tcred;
int err = 0;
int i;
struct task_struct *task;
@@ -1018,14 +1018,16 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
* capabilities, superuser privileges or the same
* userid as the target process.
*/
- cred = current->cred;
- tcred = task->cred;
+ rcu_read_lock();
+ tcred = __task_cred(task);
if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
cred->uid != tcred->suid && cred->uid != tcred->uid &&
!capable(CAP_SYS_NICE)) {
+ rcu_read_unlock();
err = -EPERM;
goto out2;
}
+ rcu_read_unlock();

err = security_task_movememory(task);
if (err)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index c156ffb..235b7f7 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -298,9 +298,9 @@ static void dump_tasks(const struct mem_cgroup *mem)

task_lock(p);
printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d %3d %s\n",
- p->pid, p->cred->uid, p->tgid, p->mm->total_vm,
- get_mm_rss(p->mm), (int)task_cpu(p), p->oomkilladj,
- p->comm);
+ p->pid, __task_cred(p)->uid, p->tgid,
+ p->mm->total_vm, get_mm_rss(p->mm), (int)task_cpu(p),
+ p->oomkilladj, p->comm);
task_unlock(p);
} while_each_thread(g, p);
}
diff --git a/security/commoncap.c b/security/commoncap.c
index 2de5cbe..d6456b0 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -50,10 +50,13 @@ EXPORT_SYMBOL(cap_netlink_recv);
*/
int cap_capable (struct task_struct *tsk, int cap)
{
+ __u32 cap_raised;
+
/* Derived from include/linux/sched.h:capable. */
- if (cap_raised(tsk->cred->cap_effective, cap))
- return 0;
- return -EPERM;
+ rcu_read_lock();
+ cap_raised = cap_raised(__task_cred(tsk)->cap_effective, cap);
+ rcu_read_unlock();
+ return cap_raised ? 0 : -EPERM;
}

int cap_settime(struct timespec *ts, struct timezone *tz)
@@ -65,34 +68,42 @@ int cap_settime(struct timespec *ts, struct timezone *tz)

int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
{
- /* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
- if (cap_issubset(child->cred->cap_permitted,
- current->cred->cap_permitted))
- return 0;
- if (capable(CAP_SYS_PTRACE))
- return 0;
- return -EPERM;
+ int ret = 0;
+
+ rcu_read_lock();
+ if (!cap_issubset(child->cred->cap_permitted,
+ current->cred->cap_permitted) &&
+ !capable(CAP_SYS_PTRACE))
+ ret = -EPERM;
+ rcu_read_unlock();
+ return ret;
}

int cap_ptrace_traceme(struct task_struct *parent)
{
- if (cap_issubset(current->cred->cap_permitted,
- parent->cred->cap_permitted))
- return 0;
- if (has_capability(parent, CAP_SYS_PTRACE))
- return 0;
- return -EPERM;
+ int ret = 0;
+
+ rcu_read_lock();
+ if (!cap_issubset(current->cred->cap_permitted,
+ parent->cred->cap_permitted) &&
+ !has_capability(parent, CAP_SYS_PTRACE))
+ ret = -EPERM;
+ rcu_read_unlock();
+ return ret;
}

int cap_capget (struct task_struct *target, kernel_cap_t *effective,
kernel_cap_t *inheritable, kernel_cap_t *permitted)
{
- struct cred *cred = target->cred;
+ const struct cred *cred;

/* Derived from kernel/capability.c:sys_capget. */
+ rcu_read_lock();
+ cred = __task_cred(target);
*effective = cred->cap_effective;
*inheritable = cred->cap_inheritable;
*permitted = cred->cap_permitted;
+ rcu_read_unlock();
return 0;
}

@@ -398,7 +409,7 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)

int cap_bprm_secureexec (struct linux_binprm *bprm)
{
- const struct cred *cred = current->cred;
+ const struct cred *cred = current_cred();

if (cred->uid != 0) {
if (bprm->cap_effective)
@@ -476,11 +487,11 @@ static inline void cap_emulate_setxuid (int old_ruid, int old_euid,
if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
(cred->uid != 0 && cred->euid != 0 && cred->suid != 0) &&
!issecure(SECURE_KEEP_CAPS)) {
- cap_clear (cred->cap_permitted);
- cap_clear (cred->cap_effective);
+ cap_clear(cred->cap_permitted);
+ cap_clear(cred->cap_effective);
}
if (old_euid == 0 && cred->euid != 0) {
- cap_clear (cred->cap_effective);
+ cap_clear(cred->cap_effective);
}
if (old_euid != 0 && cred->euid == 0) {
cred->cap_effective = cred->cap_permitted;
@@ -547,9 +558,14 @@ int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
*/
static inline int cap_safe_nice(struct task_struct *p)
{
- if (!cap_issubset(p->cred->cap_permitted,
- current->cred->cap_permitted) &&
- !capable(CAP_SYS_NICE))
+ int is_subset;
+
+ rcu_read_lock();
+ is_subset = cap_issubset(__task_cred(p)->cap_permitted,
+ current_cred()->cap_permitted);
+ rcu_read_unlock();
+
+ if (!is_subset && !capable(CAP_SYS_NICE))
return -EPERM;
return 0;
}
diff --git a/security/keys/permission.c b/security/keys/permission.c
index baf3d5f..13c3616 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -22,13 +22,16 @@ int key_task_permission(const key_ref_t key_ref,
struct task_struct *context,
key_perm_t perm)
{
- struct cred *cred = context->cred;
+ const struct cred *cred;
struct key *key;
key_perm_t kperm;
int ret;

key = key_ref_to_ptr(key_ref);

+ rcu_read_lock();
+ cred = __task_cred(context);
+
/* use the second 8-bits of permissions for keys the caller owns */
if (key->uid == cred->fsuid) {
kperm = key->perm >> 16;
@@ -43,10 +46,7 @@ int key_task_permission(const key_ref_t key_ref,
goto use_these_perms;
}

- spin_lock(&cred->lock);
ret = groups_search(cred->group_info, key->gid);
- spin_unlock(&cred->lock);
-
if (ret) {
kperm = key->perm >> 8;
goto use_these_perms;
@@ -57,6 +57,8 @@ int key_task_permission(const key_ref_t key_ref,
kperm = key->perm;

use_these_perms:
+ rcu_read_lock();
+
/* use the top 8-bits of permissions for keys the caller possesses
* - possessor permissions are additive with other permissions
*/
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index c9ccbdb..d3fa0ae 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -412,10 +412,13 @@ key_ref_t search_process_keyrings(struct key_type *type,
struct task_struct *context)
{
struct request_key_auth *rka;
+ struct cred *cred;
key_ref_t key_ref, ret, err;

might_sleep();

+ cred = get_task_cred(context);
+
/* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
* searchable, but we failed to find a key or we found a negative key;
* otherwise we want to return a sample error (probably -EACCES) if
@@ -428,9 +431,9 @@ key_ref_t search_process_keyrings(struct key_type *type,
err = ERR_PTR(-EAGAIN);

/* search the thread keyring first */
- if (context->cred->thread_keyring) {
+ if (cred->thread_keyring) {
key_ref = keyring_search_aux(
- make_key_ref(context->cred->thread_keyring, 1),
+ make_key_ref(cred->thread_keyring, 1),
context, type, description, match);
if (!IS_ERR(key_ref))
goto found;
@@ -495,9 +498,9 @@ key_ref_t search_process_keyrings(struct key_type *type,
}
}
/* or search the user-session keyring */
- else if (context->cred->user->session_keyring) {
+ else if (cred->user->session_keyring) {
key_ref = keyring_search_aux(
- make_key_ref(context->cred->user->session_keyring, 1),
+ make_key_ref(cred->user->session_keyring, 1),
context, type, description, match);
if (!IS_ERR(key_ref))
goto found;
@@ -519,20 +522,20 @@ key_ref_t search_process_keyrings(struct key_type *type,
* search the keyrings of the process mentioned there
* - we don't permit access to request_key auth keys via this method
*/
- if (context->cred->request_key_auth &&
+ if (cred->request_key_auth &&
context == current &&
type != &key_type_request_key_auth
) {
/* defend against the auth key being revoked */
- down_read(&context->cred->request_key_auth->sem);
+ down_read(&cred->request_key_auth->sem);

- if (key_validate(context->cred->request_key_auth) == 0) {
- rka = context->cred->request_key_auth->payload.data;
+ if (key_validate(cred->request_key_auth) == 0) {
+ rka = cred->request_key_auth->payload.data;

key_ref = search_process_keyrings(type, description,
match, rka->context);

- up_read(&context->cred->request_key_auth->sem);
+ up_read(&cred->request_key_auth->sem);

if (!IS_ERR(key_ref))
goto found;
@@ -549,7 +552,7 @@ key_ref_t search_process_keyrings(struct key_type *type,
break;
}
} else {
- up_read(&context->cred->request_key_auth->sem);
+ up_read(&cred->request_key_auth->sem);
}
}

@@ -557,6 +560,7 @@ key_ref_t search_process_keyrings(struct key_type *type,
key_ref = ret ? ret : err;

found:
+ put_cred(cred);
return key_ref;

} /* end search_process_keyrings() */
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 10715d1..c863036 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -95,13 +95,18 @@ extern void selnl_notify_setenforce(int val);
static int task_has_security(struct task_struct *tsk,
u32 perms)
{
- struct task_security_struct *tsec;
-
- tsec = tsk->cred->security;
+ const struct task_security_struct *tsec;
+ u32 sid = 0;
+
+ rcu_read_lock();
+ tsec = __task_cred(tsk)->security;
+ if (tsec)
+ sid = tsec->sid;
+ rcu_read_unlock();
if (!tsec)
return -EACCES;

- return avc_has_perm(tsec->sid, SECINITSID_SECURITY,
+ return avc_has_perm(sid, SECINITSID_SECURITY,
SECCLASS_SECURITY, perms, NULL);
}

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 9d2e227..3e3dcbf 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -30,6 +30,8 @@

#include "smack.h"

+#define task_security(task) (task_cred_xxx((task), security))
+
/*
* I hope these are the hokeyist lines of code in the module. Casey.
*/
@@ -1012,7 +1014,7 @@ static void smack_cred_free(struct cred *cred)
*/
static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
{
- return smk_curacc(p->cred->security, MAY_WRITE);
+ return smk_curacc(task_security(p), MAY_WRITE);
}

/**
@@ -1023,7 +1025,7 @@ static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
*/
static int smack_task_getpgid(struct task_struct *p)
{
- return smk_curacc(p->cred->security, MAY_READ);
+ return smk_curacc(task_security(p), MAY_READ);
}

/**
@@ -1034,7 +1036,7 @@ static int smack_task_getpgid(struct task_struct *p)
*/
static int smack_task_getsid(struct task_struct *p)
{
- return smk_curacc(p->cred->security, MAY_READ);
+ return smk_curacc(task_security(p), MAY_READ);
}

/**
@@ -1046,7 +1048,7 @@ static int smack_task_getsid(struct task_struct *p)
*/
static void smack_task_getsecid(struct task_struct *p, u32 *secid)
{
- *secid = smack_to_secid(p->cred->security);
+ *secid = smack_to_secid(task_security(p));
}

/**
@@ -1062,7 +1064,7 @@ static int smack_task_setnice(struct task_struct *p, int nice)

rc = cap_task_setnice(p, nice);
if (rc == 0)
- rc = smk_curacc(p->cred->security, MAY_WRITE);
+ rc = smk_curacc(task_security(p), MAY_WRITE);
return rc;
}

@@ -1079,7 +1081,7 @@ static int smack_task_setioprio(struct task_struct *p, int ioprio)

rc = cap_task_setioprio(p, ioprio);
if (rc == 0)
- rc = smk_curacc(p->cred->security, MAY_WRITE);
+ rc = smk_curacc(task_security(p), MAY_WRITE);
return rc;
}

@@ -1091,7 +1093,7 @@ static int smack_task_setioprio(struct task_struct *p, int ioprio)
*/
static int smack_task_getioprio(struct task_struct *p)
{
- return smk_curacc(p->cred->security, MAY_READ);
+ return smk_curacc(task_security(p), MAY_READ);
}

/**
@@ -1109,7 +1111,7 @@ static int smack_task_setscheduler(struct task_struct *p, int policy,

rc = cap_task_setscheduler(p, policy, lp);
if (rc == 0)
- rc = smk_curacc(p->cred->security, MAY_WRITE);
+ rc = smk_curacc(task_security(p), MAY_WRITE);
return rc;
}

@@ -1121,7 +1123,7 @@ static int smack_task_setscheduler(struct task_struct *p, int policy,
*/
static int smack_task_getscheduler(struct task_struct *p)
{
- return smk_curacc(p->cred->security, MAY_READ);
+ return smk_curacc(task_security(p), MAY_READ);
}

/**
@@ -1132,7 +1134,7 @@ static int smack_task_getscheduler(struct task_struct *p)
*/
static int smack_task_movememory(struct task_struct *p)
{
- return smk_curacc(p->cred->security, MAY_WRITE);
+ return smk_curacc(task_security(p), MAY_WRITE);
}

/**
@@ -1155,13 +1157,13 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
* can write the receiver.
*/
if (secid == 0)
- return smk_curacc(p->cred->security, MAY_WRITE);
+ return smk_curacc(task_security(p), MAY_WRITE);
/*
* If the secid isn't 0 we're dealing with some USB IO
* specific behavior. This is not clean. For one thing
* we can't take privilege into account.
*/
- return smk_access(smack_from_secid(secid), p->cred->security, MAY_WRITE);
+ return smk_access(smack_from_secid(secid), task_security(p), MAY_WRITE);
}

/**
@@ -1174,7 +1176,7 @@ static int smack_task_wait(struct task_struct *p)
{
int rc;

- rc = smk_access(current->cred->security, p->cred->security, MAY_WRITE);
+ rc = smk_access(current_security(), task_security(p), MAY_WRITE);
if (rc == 0)
return 0;

@@ -1205,7 +1207,7 @@ static int smack_task_wait(struct task_struct *p)
static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
{
struct inode_smack *isp = inode->i_security;
- isp->smk_inode = p->cred->security;
+ isp->smk_inode = task_security(p);
}

/*
@@ -2010,7 +2012,7 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
if (strcmp(name, "current") != 0)
return -EINVAL;

- cp = kstrdup(p->cred->security, GFP_KERNEL);
+ cp = kstrdup(task_security(p), GFP_KERNEL);
if (cp == NULL)
return -ENOMEM;



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  Last update: 2008-08-06 17:57    [from the cache]
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