fuse: do not use iocb after it may have been freed

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commit 7cabc61e01 upstream.

There's a race in fuse_direct_IO(), whereby is_sync_kiocb() is called on an
iocb that could have been freed if async io has already completed.  The fix
in this case is simple and obvious: cache the result before starting io.

It was discovered by KASan:

kernel: ==================================================================
kernel: BUG: KASan: use after free in fuse_direct_IO+0xb1a/0xcc0 at addr ffff88036c414390

Signed-off-by: Robert Doebbelin <robert@quobyte.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: bcba24ccdc ("fuse: enable asynchronous processing direct IO")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Robert Doebbelin 2016-03-07 09:50:56 +01:00 • committed by Greg Kroah-Hartman

parent 2775a60447

commit 32b9807433

1 changed files with 4 additions and 3 deletions

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fs/fuse/file.c

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