commit 4c17a6d56b upstream.
This might lead to local privilege escalation (code execution as
kernel) for systems where the following conditions are met:
- CONFIG_CIFS_SMB2 and CONFIG_CIFS_POSIX are enabled
- a cifs filesystem is mounted where:
- the mount option "vers" was used and set to a value >=2.0
- the attacker has write access to at least one file on the filesystem
To attack this, an attacker would have to guess the target_tcon
pointer (but guessing wrong doesn't cause a crash, it just returns an
error code) and win a narrow race.
Signed-off-by: Jann Horn <jann@thejh.net>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
c1589311c9