path: root/security/keys/keyctl.c
diff options
authorEric Biggers <ebiggers@google.com>2017-04-18 15:31:09 +0100
committerDavid Howells <dhowells@redhat.com>2017-04-18 15:31:49 +0100
commitc9f838d104fed6f2f61d68164712e3204bf5271b (patch)
tree11f3973c37a4070994d1f64ed444a233ef7f10b4 /security/keys/keyctl.c
parentKEYS: Change the name of the dead type to ".dead" to prevent user access (diff)
KEYS: fix keyctl_set_reqkey_keyring() to not leak thread keyrings
This fixes CVE-2017-7472. Running the following program as an unprivileged user exhausts kernel memory by leaking thread keyrings: #include <keyutils.h> int main() { for (;;) keyctl_set_reqkey_keyring(KEY_REQKEY_DEFL_THREAD_KEYRING); } Fix it by only creating a new thread keyring if there wasn't one before. To make things more consistent, make install_thread_keyring_to_cred() and install_process_keyring_to_cred() both return 0 if the corresponding keyring is already present. Fixes: d84f4f992cbd ("CRED: Inaugurate COW credentials") Cc: stable@vger.kernel.org # 2.6.29+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to '')
1 files changed, 4 insertions, 7 deletions
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index ab082a2e8fdd..4ad3212adebe 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1258,8 +1258,8 @@ error:
* Read or set the default keyring in which request_key() will cache keys and
* return the old setting.
- * If a process keyring is specified then this will be created if it doesn't
- * yet exist. The old setting will be returned if successful.
+ * If a thread or process keyring is specified then it will be created if it
+ * doesn't yet exist. The old setting will be returned if successful.
long keyctl_set_reqkey_keyring(int reqkey_defl)
@@ -1284,11 +1284,8 @@ long keyctl_set_reqkey_keyring(int reqkey_defl)
ret = install_process_keyring_to_cred(new);
- if (ret < 0) {
- if (ret != -EEXIST)
- goto error;
- ret = 0;
- }
+ if (ret < 0)
+ goto error;
goto set;