Commit d84f4f99 authored by David Howells's avatar David Howells Committed by James Morris

CRED: Inaugurate COW credentials

Inaugurate copy-on-write credentials management.  This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.

A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().

With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:

	struct cred *new = prepare_creds();
	int ret = blah(new);
	if (ret < 0) {
		abort_creds(new);
		return ret;
	}
	return commit_creds(new);

There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.

To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const.  The purpose of this is compile-time
discouragement of altering credentials through those pointers.  Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:

  (1) Its reference count may incremented and decremented.

  (2) The keyrings to which it points may be modified, but not replaced.

The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).

This patch and the preceding patches have been tested with the LTP SELinux
testsuite.

This patch makes several logical sets of alteration:

 (1) execve().

     This now prepares and commits credentials in various places in the
     security code rather than altering the current creds directly.

 (2) Temporary credential overrides.

     do_coredump() and sys_faccessat() now prepare their own credentials and
     temporarily override the ones currently on the acting thread, whilst
     preventing interference from other threads by holding cred_replace_mutex
     on the thread being dumped.

     This will be replaced in a future patch by something that hands down the
     credentials directly to the functions being called, rather than altering
     the task's objective credentials.

 (3) LSM interface.

     A number of functions have been changed, added or removed:

     (*) security_capset_check(), ->capset_check()
     (*) security_capset_set(), ->capset_set()

     	 Removed in favour of security_capset().

     (*) security_capset(), ->capset()

     	 New.  This is passed a pointer to the new creds, a pointer to the old
     	 creds and the proposed capability sets.  It should fill in the new
     	 creds or return an error.  All pointers, barring the pointer to the
     	 new creds, are now const.

     (*) security_bprm_apply_creds(), ->bprm_apply_creds()

     	 Changed; now returns a value, which will cause the process to be
     	 killed if it's an error.

     (*) security_task_alloc(), ->task_alloc_security()

     	 Removed in favour of security_prepare_creds().

     (*) security_cred_free(), ->cred_free()

     	 New.  Free security data attached to cred->security.

     (*) security_prepare_creds(), ->cred_prepare()

     	 New. Duplicate any security data attached to cred->security.

     (*) security_commit_creds(), ->cred_commit()

     	 New. Apply any security effects for the upcoming installation of new
     	 security by commit_creds().

     (*) security_task_post_setuid(), ->task_post_setuid()

     	 Removed in favour of security_task_fix_setuid().

     (*) security_task_fix_setuid(), ->task_fix_setuid()

     	 Fix up the proposed new credentials for setuid().  This is used by
     	 cap_set_fix_setuid() to implicitly adjust capabilities in line with
     	 setuid() changes.  Changes are made to the new credentials, rather
     	 than the task itself as in security_task_post_setuid().

     (*) security_task_reparent_to_init(), ->task_reparent_to_init()

     	 Removed.  Instead the task being reparented to init is referred
     	 directly to init's credentials.

	 NOTE!  This results in the loss of some state: SELinux's osid no
	 longer records the sid of the thread that forked it.

     (*) security_key_alloc(), ->key_alloc()
     (*) security_key_permission(), ->key_permission()

     	 Changed.  These now take cred pointers rather than task pointers to
     	 refer to the security context.

 (4) sys_capset().

     This has been simplified and uses less locking.  The LSM functions it
     calls have been merged.

 (5) reparent_to_kthreadd().

     This gives the current thread the same credentials as init by simply using
     commit_thread() to point that way.

 (6) __sigqueue_alloc() and switch_uid()

     __sigqueue_alloc() can't stop the target task from changing its creds
     beneath it, so this function gets a reference to the currently applicable
     user_struct which it then passes into the sigqueue struct it returns if
     successful.

     switch_uid() is now called from commit_creds(), and possibly should be
     folded into that.  commit_creds() should take care of protecting
     __sigqueue_alloc().

 (7) [sg]et[ug]id() and co and [sg]et_current_groups.

     The set functions now all use prepare_creds(), commit_creds() and
     abort_creds() to build and check a new set of credentials before applying
     it.

     security_task_set[ug]id() is called inside the prepared section.  This
     guarantees that nothing else will affect the creds until we've finished.

     The calling of set_dumpable() has been moved into commit_creds().

     Much of the functionality of set_user() has been moved into
     commit_creds().

     The get functions all simply access the data directly.

 (8) security_task_prctl() and cap_task_prctl().

     security_task_prctl() has been modified to return -ENOSYS if it doesn't
     want to handle a function, or otherwise return the return value directly
     rather than through an argument.

     Additionally, cap_task_prctl() now prepares a new set of credentials, even
     if it doesn't end up using it.

 (9) Keyrings.

     A number of changes have been made to the keyrings code:

     (a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
     	 all been dropped and built in to the credentials functions directly.
     	 They may want separating out again later.

     (b) key_alloc() and search_process_keyrings() now take a cred pointer
     	 rather than a task pointer to specify the security context.

     (c) copy_creds() gives a new thread within the same thread group a new
     	 thread keyring if its parent had one, otherwise it discards the thread
     	 keyring.

     (d) The authorisation key now points directly to the credentials to extend
     	 the search into rather pointing to the task that carries them.

     (e) Installing thread, process or session keyrings causes a new set of
     	 credentials to be created, even though it's not strictly necessary for
     	 process or session keyrings (they're shared).

(10) Usermode helper.

     The usermode helper code now carries a cred struct pointer in its
     subprocess_info struct instead of a new session keyring pointer.  This set
     of credentials is derived from init_cred and installed on the new process
     after it has been cloned.

     call_usermodehelper_setup() allocates the new credentials and
     call_usermodehelper_freeinfo() discards them if they haven't been used.  A
     special cred function (prepare_usermodeinfo_creds()) is provided
     specifically for call_usermodehelper_setup() to call.

     call_usermodehelper_setkeys() adjusts the credentials to sport the
     supplied keyring as the new session keyring.

(11) SELinux.

     SELinux has a number of changes, in addition to those to support the LSM
     interface changes mentioned above:

     (a) selinux_setprocattr() no longer does its check for whether the
     	 current ptracer can access processes with the new SID inside the lock
     	 that covers getting the ptracer's SID.  Whilst this lock ensures that
     	 the check is done with the ptracer pinned, the result is only valid
     	 until the lock is released, so there's no point doing it inside the
     	 lock.

(12) is_single_threaded().

     This function has been extracted from selinux_setprocattr() and put into
     a file of its own in the lib/ directory as join_session_keyring() now
     wants to use it too.

     The code in SELinux just checked to see whether a task shared mm_structs
     with other tasks (CLONE_VM), but that isn't good enough.  We really want
     to know if they're part of the same thread group (CLONE_THREAD).

(13) nfsd.

     The NFS server daemon now has to use the COW credentials to set the
     credentials it is going to use.  It really needs to pass the credentials
     down to the functions it calls, but it can't do that until other patches
     in this series have been applied.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarJames Morris <jmorris@namei.org>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 745ca247
......@@ -1007,13 +1007,12 @@ int flush_old_exec(struct linux_binprm * bprm)
*/
current->mm->task_size = TASK_SIZE;
if (bprm->e_uid != current_euid() || bprm->e_gid != current_egid()) {
suid_keys(current);
if (bprm->e_uid != current_euid() ||
bprm->e_gid != current_egid()) {
set_dumpable(current->mm, suid_dumpable);
current->pdeath_signal = 0;
} else if (file_permission(bprm->file, MAY_READ) ||
(bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
suid_keys(current);
set_dumpable(current->mm, suid_dumpable);
}
......@@ -1096,10 +1095,8 @@ void compute_creds(struct linux_binprm *bprm)
{
int unsafe;
if (bprm->e_uid != current_uid()) {
suid_keys(current);
if (bprm->e_uid != current_uid())
current->pdeath_signal = 0;
}
exec_keys(current);
task_lock(current);
......@@ -1709,8 +1706,9 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
struct linux_binfmt * binfmt;
struct inode * inode;
struct file * file;
const struct cred *old_cred;
struct cred *cred;
int retval = 0;
int fsuid = current_fsuid();
int flag = 0;
int ispipe = 0;
unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
......@@ -1723,12 +1721,20 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
binfmt = current->binfmt;
if (!binfmt || !binfmt->core_dump)
goto fail;
cred = prepare_creds();
if (!cred) {
retval = -ENOMEM;
goto fail;
}
down_write(&mm->mmap_sem);
/*
* If another thread got here first, or we are not dumpable, bail out.
*/
if (mm->core_state || !get_dumpable(mm)) {
up_write(&mm->mmap_sem);
put_cred(cred);
goto fail;
}
......@@ -1739,12 +1745,16 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
*/
if (get_dumpable(mm) == 2) { /* Setuid core dump mode */
flag = O_EXCL; /* Stop rewrite attacks */
current->cred->fsuid = 0; /* Dump root private */
cred->fsuid = 0; /* Dump root private */
}
retval = coredump_wait(exit_code, &core_state);
if (retval < 0)
if (retval < 0) {
put_cred(cred);
goto fail;
}
old_cred = override_creds(cred);
/*
* Clear any false indication of pending signals that might
......@@ -1835,7 +1845,8 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
if (helper_argv)
argv_free(helper_argv);
current->cred->fsuid = fsuid;
revert_creds(old_cred);
put_cred(cred);
coredump_finish(mm);
fail:
return retval;
......
......@@ -27,55 +27,67 @@ int nfsexp_flags(struct svc_rqst *rqstp, struct svc_export *exp)
int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
{
struct cred *act_as = current->cred ;
struct svc_cred cred = rqstp->rq_cred;
struct group_info *rqgi;
struct group_info *gi;
struct cred *new;
int i;
int flags = nfsexp_flags(rqstp, exp);
int ret;
new = prepare_creds();
if (!new)
return -ENOMEM;
new->fsuid = rqstp->rq_cred.cr_uid;
new->fsgid = rqstp->rq_cred.cr_gid;
rqgi = rqstp->rq_cred.cr_group_info;
if (flags & NFSEXP_ALLSQUASH) {
cred.cr_uid = exp->ex_anon_uid;
cred.cr_gid = exp->ex_anon_gid;
cred.cr_group_info = groups_alloc(0);
new->fsuid = exp->ex_anon_uid;
new->fsgid = exp->ex_anon_gid;
gi = groups_alloc(0);
} else if (flags & NFSEXP_ROOTSQUASH) {
struct group_info *gi;
if (!cred.cr_uid)
cred.cr_uid = exp->ex_anon_uid;
if (!cred.cr_gid)
cred.cr_gid = exp->ex_anon_gid;
gi = groups_alloc(cred.cr_group_info->ngroups);
if (gi)
for (i = 0; i < cred.cr_group_info->ngroups; i++) {
if (!GROUP_AT(cred.cr_group_info, i))
GROUP_AT(gi, i) = exp->ex_anon_gid;
else
GROUP_AT(gi, i) = GROUP_AT(cred.cr_group_info, i);
}
cred.cr_group_info = gi;
} else
get_group_info(cred.cr_group_info);
if (cred.cr_uid != (uid_t) -1)
act_as->fsuid = cred.cr_uid;
else
act_as->fsuid = exp->ex_anon_uid;
if (cred.cr_gid != (gid_t) -1)
act_as->fsgid = cred.cr_gid;
else
act_as->fsgid = exp->ex_anon_gid;
if (!new->fsuid)
new->fsuid = exp->ex_anon_uid;
if (!new->fsgid)
new->fsgid = exp->ex_anon_gid;
if (!cred.cr_group_info)
return -ENOMEM;
ret = set_groups(act_as, cred.cr_group_info);
put_group_info(cred.cr_group_info);
if ((cred.cr_uid)) {
act_as->cap_effective =
cap_drop_nfsd_set(act_as->cap_effective);
gi = groups_alloc(rqgi->ngroups);
if (!gi)
goto oom;
for (i = 0; i < rqgi->ngroups; i++) {
if (!GROUP_AT(rqgi, i))
GROUP_AT(gi, i) = exp->ex_anon_gid;
else
GROUP_AT(gi, i) = GROUP_AT(rqgi, i);
}
} else {
act_as->cap_effective =
cap_raise_nfsd_set(act_as->cap_effective,
act_as->cap_permitted);
gi = get_group_info(rqgi);
}
if (new->fsuid == (uid_t) -1)
new->fsuid = exp->ex_anon_uid;
if (new->fsgid == (gid_t) -1)
new->fsgid = exp->ex_anon_gid;
ret = set_groups(new, gi);
put_group_info(gi);
if (!ret)
goto error;
if (new->uid)
new->cap_effective = cap_drop_nfsd_set(new->cap_effective);
else
new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
new->cap_permitted);
return commit_creds(new);
oom:
ret = -ENOMEM;
error:
abort_creds(new);
return ret;
}
......@@ -54,20 +54,26 @@
static struct path rec_dir;
static int rec_dir_init = 0;
static void
nfs4_save_user(uid_t *saveuid, gid_t *savegid)
static int
nfs4_save_creds(const struct cred **original_creds)
{
*saveuid = current->cred->fsuid;
*savegid = current->cred->fsgid;
current->cred->fsuid = 0;
current->cred->fsgid = 0;
struct cred *new;
new = prepare_creds();
if (!new)
return -ENOMEM;
new->fsuid = 0;
new->fsgid = 0;
*original_creds = override_creds(new);
put_cred(new);
return 0;
}
static void
nfs4_reset_user(uid_t saveuid, gid_t savegid)
nfs4_reset_creds(const struct cred *original)
{
current->cred->fsuid = saveuid;
current->cred->fsgid = savegid;
revert_creds(original);
}
static void
......@@ -129,10 +135,9 @@ nfsd4_sync_rec_dir(void)
int
nfsd4_create_clid_dir(struct nfs4_client *clp)
{
const struct cred *original_cred;
char *dname = clp->cl_recdir;
struct dentry *dentry;
uid_t uid;
gid_t gid;
int status;
dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
......@@ -140,7 +145,9 @@ nfsd4_create_clid_dir(struct nfs4_client *clp)
if (!rec_dir_init || clp->cl_firststate)
return 0;
nfs4_save_user(&uid, &gid);
status = nfs4_save_creds(&original_cred);
if (status < 0)
return status;
/* lock the parent */
mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
......@@ -168,7 +175,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp)
clp->cl_firststate = 1;
nfsd4_sync_rec_dir();
}
nfs4_reset_user(uid, gid);
nfs4_reset_creds(original_cred);
dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
return status;
}
......@@ -211,20 +218,21 @@ nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
static int
nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
{
const struct cred *original_cred;
struct file *filp;
struct dentry_list_arg dla = {
.parent = dir,
};
struct list_head *dentries = &dla.dentries;
struct dentry_list *child;
uid_t uid;
gid_t gid;
int status;
if (!rec_dir_init)
return 0;
nfs4_save_user(&uid, &gid);
status = nfs4_save_creds(&original_cred);
if (status < 0)
return status;
filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY,
current_cred());
......@@ -250,7 +258,7 @@ nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
dput(child->dentry);
kfree(child);
}
nfs4_reset_user(uid, gid);
nfs4_reset_creds(original_cred);
return status;
}
......@@ -312,8 +320,7 @@ nfsd4_unlink_clid_dir(char *name, int namlen)
void
nfsd4_remove_clid_dir(struct nfs4_client *clp)
{
uid_t uid;
gid_t gid;
const struct cred *original_cred;
int status;
if (!rec_dir_init || !clp->cl_firststate)
......@@ -323,9 +330,13 @@ nfsd4_remove_clid_dir(struct nfs4_client *clp)
if (status)
goto out;
clp->cl_firststate = 0;
nfs4_save_user(&uid, &gid);
status = nfs4_save_creds(&original_cred);
if (status < 0)
goto out;
status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
nfs4_reset_user(uid, gid);
nfs4_reset_creds(original_cred);
if (status == 0)
nfsd4_sync_rec_dir();
mnt_drop_write(rec_dir.mnt);
......@@ -402,16 +413,21 @@ nfsd4_recdir_load(void) {
void
nfsd4_init_recdir(char *rec_dirname)
{
uid_t uid = 0;
gid_t gid = 0;
int status;
const struct cred *original_cred;
int status;
printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
rec_dirname);
BUG_ON(rec_dir_init);
nfs4_save_user(&uid, &gid);
status = nfs4_save_creds(&original_cred);
if (status < 0) {
printk("NFSD: Unable to change credentials to find recovery"
" directory: error %d\n",
status);
return;
}
status = kern_path(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
&rec_dir);
......@@ -421,7 +437,7 @@ nfsd4_init_recdir(char *rec_dirname)
if (!status)
rec_dir_init = 1;
nfs4_reset_user(uid, gid);
nfs4_reset_creds(original_cred);
}
void
......
......@@ -186,9 +186,14 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
* access control settings being in effect, we cannot
* fix that case easily.
*/
current->cred->cap_effective =
cap_raise_nfsd_set(current->cred->cap_effective,
current->cred->cap_permitted);
struct cred *new = prepare_creds();
if (!new)
return nfserrno(-ENOMEM);
new->cap_effective =
cap_raise_nfsd_set(new->cap_effective,
new->cap_permitted);
put_cred(override_creds(new));
put_cred(new);
} else {
error = nfsd_setuser_and_check_port(rqstp, exp);
if (error)
......
......@@ -425,30 +425,33 @@ asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len)
*/
asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
{
struct cred *cred = current->cred;
const struct cred *old_cred;
struct cred *override_cred;
struct path path;
struct inode *inode;
int old_fsuid, old_fsgid;
kernel_cap_t uninitialized_var(old_cap); /* !SECURE_NO_SETUID_FIXUP */
int res;
if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
return -EINVAL;
old_fsuid = cred->fsuid;
old_fsgid = cred->fsgid;
override_cred = prepare_creds();
if (!override_cred)
return -ENOMEM;
cred->fsuid = cred->uid;
cred->fsgid = cred->gid;
override_cred->fsuid = override_cred->uid;
override_cred->fsgid = override_cred->gid;
if (!issecure(SECURE_NO_SETUID_FIXUP)) {
/* Clear the capabilities if we switch to a non-root user */
if (current->cred->uid)
old_cap = cap_set_effective(__cap_empty_set);
if (override_cred->uid)
cap_clear(override_cred->cap_effective);
else
old_cap = cap_set_effective(cred->cap_permitted);
override_cred->cap_effective =
override_cred->cap_permitted;
}
old_cred = override_creds(override_cred);
res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
if (res)
goto out;
......@@ -485,12 +488,8 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
out_path_release:
path_put(&path);
out:
cred->fsuid = old_fsuid;
cred->fsgid = old_fsgid;
if (!issecure(SECURE_NO_SETUID_FIXUP))
cap_set_effective(old_cap);
revert_creds(old_cred);
put_cred(override_cred);
return res;
}
......
......@@ -454,8 +454,10 @@ extern int __audit_mq_timedsend(mqd_t mqdes, size_t msg_len, unsigned int msg_pr
extern int __audit_mq_timedreceive(mqd_t mqdes, size_t msg_len, unsigned int __user *u_msg_prio, const struct timespec __user *u_abs_timeout);
extern int __audit_mq_notify(mqd_t mqdes, const struct sigevent __user *u_notification);
extern int __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat);
extern void __audit_log_bprm_fcaps(struct linux_binprm *bprm, kernel_cap_t *pP, kernel_cap_t *pE);
extern int __audit_log_capset(pid_t pid, kernel_cap_t *eff, kernel_cap_t *inh, kernel_cap_t *perm);
extern int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
const struct cred *new,
const struct cred *old);
extern int __audit_log_capset(pid_t pid, const struct cred *new, const struct cred *old);
static inline int audit_ipc_obj(struct kern_ipc_perm *ipcp)
{
......@@ -522,16 +524,20 @@ static inline int audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
*
* -Eric
*/
static inline void audit_log_bprm_fcaps(struct linux_binprm *bprm, kernel_cap_t *pP, kernel_cap_t *pE)
static inline int audit_log_bprm_fcaps(struct linux_binprm *bprm,
const struct cred *new,
const struct cred *old)
{
if (unlikely(!audit_dummy_context()))
__audit_log_bprm_fcaps(bprm, pP, pE);
return __audit_log_bprm_fcaps(bprm, new, old);
return 0;
}
static inline int audit_log_capset(pid_t pid, kernel_cap_t *eff, kernel_cap_t *inh, kernel_cap_t *perm)
static inline int audit_log_capset(pid_t pid, const struct cred *new,
const struct cred *old)
{
if (unlikely(!audit_dummy_context()))
return __audit_log_capset(pid, eff, inh, perm);
return __audit_log_capset(pid, new, old);
return 0;
}
......@@ -566,8 +572,8 @@ extern int audit_signals;
#define audit_mq_timedreceive(d,l,p,t) ({ 0; })
#define audit_mq_notify(d,n) ({ 0; })
#define audit_mq_getsetattr(d,s) ({ 0; })
#define audit_log_bprm_fcaps(b, p, e) do { ; } while (0)
#define audit_log_capset(pid, e, i, p) ({ 0; })
#define audit_log_bprm_fcaps(b, ncr, ocr) ({ 0; })
#define audit_log_capset(pid, ncr, ocr) ({ 0; })
#define audit_ptrace(t) ((void)0)
#define audit_n_rules 0
#define audit_signals 0
......
......@@ -519,8 +519,6 @@ extern const kernel_cap_t __cap_empty_set;
extern const kernel_cap_t __cap_full_set;
extern const kernel_cap_t __cap_init_eff_set;
kernel_cap_t cap_set_effective(const kernel_cap_t pE_new);
/**
* has_capability - Determine if a task has a superior capability available
* @t: The task in question
......
......@@ -84,6 +84,8 @@ struct thread_group_cred {
struct key *process_keyring; /* keyring private to this process */
struct rcu_head rcu; /* RCU deletion hook */
};
extern void release_tgcred(struct cred *cred);
#endif
/*
......@@ -137,11 +139,30 @@ struct cred {
struct user_struct *user; /* real user ID subscription */
struct group_info *group_info; /* supplementary groups for euid/fsgid */
struct rcu_head rcu; /* RCU deletion hook */
spinlock_t lock; /* lock for pointer changes */
};
extern void __put_cred(struct cred *);
extern int copy_creds(struct task_struct *, unsigned long);
extern struct cred *prepare_creds(void);
extern struct cred *prepare_usermodehelper_creds(void);
extern int commit_creds(struct cred *);
extern void abort_creds(struct cred *);
extern const struct cred *override_creds(const struct cred *) __deprecated;
extern void revert_creds(const struct cred *) __deprecated;
extern void __init cred_init(void);
/**
* get_new_cred - Get a reference on a new set of credentials
* @cred: The new credentials to reference
*
* Get a reference on the specified set of new credentials. The caller must
* release the reference.
*/
static inline struct cred *get_new_cred(struct cred *cred)
{
atomic_inc(&cred->usage);
return cred;
}
/**
* get_cred - Get a reference on a set of credentials
......@@ -150,10 +171,9 @@ extern int copy_creds(struct task_struct *, unsigned long);
* Get a reference on the specified set of credentials. The caller must
* release the reference.
*/
static inline struct cred *get_cred(struct cred *cred)
static inline const struct cred *get_cred(const struct cred *cred)
{
atomic_inc(&cred->usage);
return cred;
return get_new_cred((struct cred *) cred);
}
/**
......@@ -166,6 +186,8 @@ static inline struct cred *get_cred(struct cred *cred)
static inline void put_cred(const struct cred *_cred)
{
struct cred *cred = (struct cred *) _cred;
BUG_ON(atomic_read(&(cred)->usage) <= 0);
if (atomic_dec_and_test(&(cred)->usage))
__put_cred(cred);
}
......@@ -250,13 +272,13 @@ static inline void put_cred(const struct cred *_cred)
__groups; \
})
#define task_cred_xxx(task, xxx) \
({ \
__typeof__(task->cred->xxx) ___val; \
rcu_read_lock(); \
___val = __task_cred((task))->xxx; \
rcu_read_unlock(); \
___val; \
#define task_cred_xxx(task, xxx) \
({ \
__typeof__(((struct cred *)NULL)->xxx) ___val; \
rcu_read_lock(); \
___val = __task_cred((task))->xxx; \
rcu_read_unlock(); \
___val; \
})
#define task_uid(task) (task_cred_xxx((task), uid))
......
......@@ -150,6 +150,8 @@ extern struct cred init_cred;
.sibling = LIST_HEAD_INIT(tsk.sibling), \
.group_leader = &tsk, \
.cred = &init_cred, \
.cred_exec_mutex = \
__MUTEX_INITIALIZER(tsk.cred_exec_mutex), \
.comm = "swapper", \
.thread = INIT_THREAD, \
.fs = &init_fs, \
......
......@@ -73,6 +73,7 @@ struct key;
struct seq_file;
struct user_struct;
struct signal_struct;
struct cred;
struct key_type;
struct key_owner;
......@@ -181,7 +182,7 @@ struct key {
extern struct key *key_alloc(struct key_type *type,
const char *desc,
uid_t uid, gid_t gid,
struct task_struct *ctx,
const struct cred *cred,
key_perm_t perm,
unsigned long flags);
......@@ -249,7 +250,7 @@ extern int key_unlink(struct key *keyring,
struct key *key);
extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
struct task_struct *ctx,
const struct cred *cred,
unsigned long flags,
struct key *dest);
......@@ -276,22 +277,12 @@ extern ctl_table key_sysctls[];
/*
* the userspace interface
*/
extern void switch_uid_keyring(struct user_struct *new_user);
extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
extern void exit_keys(struct task_struct *tsk);
extern int suid_keys(struct task_struct *tsk);
extern int install_thread_keyring_to_cred(struct cred *cred);
extern int exec_keys(struct task_struct *tsk);
extern void key_fsuid_changed(struct task_struct *tsk);
extern void key_fsgid_changed(struct task_struct *tsk);
extern void key_init(void);
#define __install_session_keyring(keyring) \
({ \
struct key *old_session = current->cred->tgcred->session_keyring; \
current->cred->tgcred->session_keyring = keyring; \
old_session; \
})
#else /* CONFIG_KEYS */
#define key_validate(k) 0
......@@ -303,11 +294,6 @@ extern void key_init(void);
#define make_key_ref(k, p) NULL
#define key_ref_to_ptr(k) NULL
#define is_key_possessed(k) 0
#define switch_uid_keyring(u) do { } while(0)
#define __install_session_keyring(k) ({ NULL; })