In gcm_mode_decrypt_contiguous_blocks(), if vmem_alloc() fails,
bcopy is called with a NULL pointer destination and a length > 0.
This results in undefined behavior. Further ctx->gcm_pt_buf is
freed but not set to NULL, leading to a potential write after
free and a double free due to missing return value handling in
crypto_update_uio(). The code as is may write to ctx->gcm_pt_buf
in gcm_decrypt_final() and may free ctx->gcm_pt_buf again in
aes_decrypt_atomic().
The fix is to slightly rework error handling and check the return
value in crypto_update_uio().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes#9659
54c8366e39