When checking for permission to view keys whilst reading from
/proc/keys, we should use the credentials with which the /proc/keys file
was opened. This is because, in a classic type of exploit, it can be
possible to bypass checks for the *current* credentials by passing the
file descriptor to a suid program.
Following commit 34dbbcdbf6 ("Make file credentials available to the
seqfile interfaces") we can finally fix it. So let's do it.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
4aa68e07d8