[PATCH] KEYS: fix key refcount leak in keyctl_read_key()

From: Eric Biggers
Date: Mon Sep 18 2017 - 14:36:46 EST

From: Eric Biggers <ebiggers@xxxxxxxxxx>

In keyctl_read_key(), if key_permission() were to return an error code
other than EACCES, we would leak a the reference to the key. This can't
actually happen currently because key_permission() can only return an
error code other than EACCES if security_key_permission() does, only
SELinux and Smack implement that hook, and neither can return an error
code other than EACCES. But it should still be fixed, as it is a bug
waiting to happen.

Fixes: 29db91906340 ("[PATCH] Keys: Add LSM hooks for key management [try #3]")
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
security/keys/keyctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 552e4460683b..365ff85d7e27 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -776,7 +776,7 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
if (ret == 0)
goto can_read_key;
if (ret != -EACCES)
- goto error;
+ goto error2;

/* we can't; see if it's searchable from this process's keyrings
* - we automatically take account of the fact that it may be