6.17-stable review patch. If anyone has any objections, please let me know.
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From: Jens Wiklander jens.wiklander@linaro.org
commit d5cf5b37064b1699d946e8b7ab4ac7d7d101814c upstream.
In register_shm_helper(), fix incorrect error handling for a call to iov_iter_extract_pages(). A case is missing for when iov_iter_extract_pages() only got some pages and return a number larger than 0, but not the requested amount.
This fixes a possible NULL pointer dereference following a bad input from ioctl(TEE_IOC_SHM_REGISTER) where parts of the buffer isn't mapped.
Cc: stable@vger.kernel.org Reported-by: Masami Ichikawa masami256@gmail.com Closes: https://lore.kernel.org/op-tee/CACOXgS-Bo2W72Nj1_44c7bntyNYOavnTjJAvUbEiQfq=... Tested-by: Masami Ichikawa masami256@gmail.com Fixes: 7bdee4157591 ("tee: Use iov_iter to better support shared buffer registration") Signed-off-by: Jens Wiklander jens.wiklander@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tee/tee_shm.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -321,6 +321,14 @@ register_shm_helper(struct tee_context * if (unlikely(len <= 0)) { ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM); goto err_free_shm_pages; + } else if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) { + /* + * If we only got a few pages, update to release the + * correct amount below. + */ + shm->num_pages = len / PAGE_SIZE; + ret = ERR_PTR(-ENOMEM); + goto err_put_shm_pages; }
/*