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-rw-r--r--security/keys/process_keys.c69
1 files changed, 63 insertions, 6 deletions
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 276d27882ce..5c23afb31ec 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -17,6 +17,7 @@
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/mutex.h>
+#include <linux/security.h>
#include <linux/user_namespace.h>
#include <asm/uaccess.h>
#include "internal.h"
@@ -487,7 +488,7 @@ static int lookup_user_key_possessed(const struct key *key, const void *target)
* - don't create special keyrings unless so requested
* - partially constructed keys aren't found unless requested
*/
-key_ref_t lookup_user_key(key_serial_t id, int create, int partial,
+key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
key_perm_t perm)
{
struct request_key_auth *rka;
@@ -503,7 +504,7 @@ try_again:
switch (id) {
case KEY_SPEC_THREAD_KEYRING:
if (!cred->thread_keyring) {
- if (!create)
+ if (!(lflags & KEY_LOOKUP_CREATE))
goto error;
ret = install_thread_keyring();
@@ -521,7 +522,7 @@ try_again:
case KEY_SPEC_PROCESS_KEYRING:
if (!cred->tgcred->process_keyring) {
- if (!create)
+ if (!(lflags & KEY_LOOKUP_CREATE))
goto error;
ret = install_process_keyring();
@@ -642,7 +643,14 @@ try_again:
break;
}
- if (!partial) {
+ /* unlink does not use the nominated key in any way, so can skip all
+ * the permission checks as it is only concerned with the keyring */
+ if (lflags & KEY_LOOKUP_FOR_UNLINK) {
+ ret = 0;
+ goto error;
+ }
+
+ if (!(lflags & KEY_LOOKUP_PARTIAL)) {
ret = wait_for_key_construction(key, true);
switch (ret) {
case -ERESTARTSYS:
@@ -660,7 +668,8 @@ try_again:
}
ret = -EIO;
- if (!partial && !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
+ if (!(lflags & KEY_LOOKUP_PARTIAL) &&
+ !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
goto invalid_key;
/* check the permissions */
@@ -702,7 +711,7 @@ long join_session_keyring(const char *name)
/* only permit this if there's a single thread in the thread group -
* this avoids us having to adjust the creds on all threads and risking
* ENOMEM */
- if (!is_single_threaded(current))
+ if (!current_is_single_threaded())
return -EMLINK;
new = prepare_creds();
@@ -760,3 +769,51 @@ error:
abort_creds(new);
return ret;
}
+
+/*
+ * Replace a process's session keyring when that process resumes userspace on
+ * behalf of one of its children
+ */
+void key_replace_session_keyring(void)
+{
+ const struct cred *old;
+ struct cred *new;
+
+ if (!current->replacement_session_keyring)
+ return;
+
+ write_lock_irq(&tasklist_lock);
+ new = current->replacement_session_keyring;
+ current->replacement_session_keyring = NULL;
+ write_unlock_irq(&tasklist_lock);
+
+ if (!new)
+ return;
+
+ old = current_cred();
+ new-> uid = old-> uid;
+ new-> euid = old-> euid;
+ new-> suid = old-> suid;
+ new->fsuid = old->fsuid;
+ new-> gid = old-> gid;
+ new-> egid = old-> egid;
+ new-> sgid = old-> sgid;
+ new->fsgid = old->fsgid;
+ new->user = get_uid(old->user);
+ new->group_info = get_group_info(old->group_info);
+
+ new->securebits = old->securebits;
+ new->cap_inheritable = old->cap_inheritable;
+ new->cap_permitted = old->cap_permitted;
+ new->cap_effective = old->cap_effective;
+ new->cap_bset = old->cap_bset;
+
+ new->jit_keyring = old->jit_keyring;
+ new->thread_keyring = key_get(old->thread_keyring);
+ new->tgcred->tgid = old->tgcred->tgid;
+ new->tgcred->process_keyring = key_get(old->tgcred->process_keyring);
+
+ security_transfer_creds(new, old);
+
+ commit_creds(new);
+}