tee: shm: fix use-after-free via temporarily dropped reference

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commit bb765d1c33 upstream.

Bump the file's refcount before moving the reference into the fd table,
not afterwards. The old code could drop the file's refcount to zero for a
short moment before calling get_file() via get_dma_buf().

This code can only be triggered on ARM systems that use Linaro's OP-TEE.

Fixes: 967c9cca2c ("tee: generic TEE subsystem")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Jann Horn 2018-04-04 21:03:21 +02:00 • committed by Greg Kroah-Hartman

parent 9a19a93bdd

commit bca7faea54

1 changed files with 3 additions and 2 deletions

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drivers/tee/tee_shm.c

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