3.16.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Eric Biggers ebiggers@google.com
commit 884bee0215fcc239b30c062c37ca29077005e064 upstream.
In keyctl_assume_authority(), if keyctl_change_reqkey_auth() were to fail, we would leak the reference to the 'authkey'. Currently this can only happen if prepare_creds() fails to allocate memory. But it still should be fixed, as it is a more severe bug waiting to happen.
This patch also moves the read of 'authkey->serial' to before the reference to the authkey is dropped. Doing the read after dropping the reference is very fragile because it assumes we still hold another reference to the key. (Which we do, in current->cred->request_key_auth, but there's no reason not to write it in the "obviously correct" way.)
Fixes: d84f4f992cbd ("CRED: Inaugurate COW credentials") Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- security/keys/keyctl.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
--- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -1401,11 +1401,9 @@ long keyctl_assume_authority(key_serial_ }
ret = keyctl_change_reqkey_auth(authkey); - if (ret < 0) - goto error; + if (ret == 0) + ret = authkey->serial; key_put(authkey); - - ret = authkey->serial; error: return ret; }