[PATCH AUTOSEL 3.18 94/98] KEYS: put keyring if install_session_keyring_to_cred() fails

Sasha Levin
2018-10-25T14:18:49Z

From: Eric Biggers <ebiggers@google.com>

[ Upstream commit d636bd9f12a66ea3775c9fabbf3f8e118253467a ]

In join_session_keyring(), if install_session_keyring_to_cred() were to
fail, we would leak the keyring reference, just like in the bug fixed by
commit 23567fd052a9 ("KEYS: Fix keyring ref leak in
join_session_keyring()"). Fortunately this cannot happen currently, but
we really should be more careful. Do this by adding and using a new
error label at which the keyring reference is dropped.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/keys/process_keys.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 85b61a3ac981..6f32ca53456a 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -808,15 +808,14 @@ long join_session_keyring(const char *name)
ret = PTR_ERR(keyring);
goto error2;
} else if (keyring == new->session_keyring) {
- key_put(keyring);
ret = 0;
- goto error2;
+ goto error3;
}

/* we've got a keyring - now to install it */
ret = install_session_keyring_to_cred(new, keyring);
if (ret < 0)
- goto error2;
+ goto error3;

commit_creds(new);
mutex_unlock(&key_session_mutex);
@@ -826,6 +825,8 @@ long join_session_keyring(const char *name)
okay:
return ret;

+error3:
+ key_put(keyring);
error2:
mutex_unlock(&key_session_mutex);
error:
--
2.17.1