diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2010-02-02 11:40:27 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-04-01 15:52:16 -0700 |
commit | 873b48a4cf4a64dd77faef25ddcf1651cef49a32 (patch) | |
tree | 2625ad66c9b82b8ae46aac60ac89d349f24e3263 /include | |
parent | 268ec2564310a552681bcbfb412c35804c06efad (diff) |
futex: Handle user space corruption gracefully
commit 51246bfd189064079c54421507236fd2723b18f3 upstream.
If the owner of a PI futex dies we fix up the pi_state and set
pi_state->owner to NULL. When a malicious or just sloppy programmed
user space application sets the futex value to 0 e.g. by calling
pthread_mutex_init(), then the futex can be acquired again. A new
waiter manages to enqueue itself on the pi_state w/o damage, but on
unlock the kernel dereferences pi_state->owner and oopses.
Prevent this by checking pi_state->owner in the unlock path. If
pi_state->owner is not current we know that user space manipulated the
futex value. Ignore the mess and return -EINVAL.
This catches the above case and also the case where a task hijacks the
futex by setting the tid value and then tries to unlock it.
Reported-by: Jermome Marchand <jmarchan@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'include')
0 files changed, 0 insertions, 0 deletions