Hi Guenter,
On Mon, Feb 26, 2018 at 09:21:19AM -0800, Guenter Roeck wrote:
On Fri, Feb 23, 2018 at 07:24:20PM +0100, gregkh@linuxfoundation.org wrote:
4.4-stable review patch. If anyone has any objections, please let me know.
From: Eric Biggers ebiggers@google.com
commit f88982679f54f75daa5b8eff3da72508f1e7422f upstream.
If the kzalloc() in binder_get_thread() fails, binder_poll() dereferences the resulting NULL pointer.
Fix it by returning POLLERR if the memory allocation failed.
This bug was found by syzkaller using fault injection.
Reported-by: syzbot syzkaller@googlegroups.com Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
drivers/android/binder.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2622,6 +2622,8 @@ static unsigned int binder_poll(struct f binder_lock(__func__); thread = binder_get_thread(proc);
- if (!thread)
return POLLERR;Noticed while merging into chromeos-4.4:
This will cause trouble in v4.4.y. Notice the call to "binder_lock(__func__)" above. This call has been removed upstream, but not in v4.4.y. As a result, the lock won't be released, which will result in subsequent hangups if/when the function is called again.
v4.9.y has the same problem. v4.14.y+ are fine.
Greg - can you fix this up yourself or do you want me to send fixup patches ? It might take a few days for me to get to it.
Guenter
Thanks for spotting this! I'll send a patch to fix it.
Eric