On Mon, Sep 22, 2025 at 10:31:58AM +0200, Jens Wiklander wrote:
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
Changes from v1
- Refactor the if statement as requested by Sumit
- Adding Tested-by: Masami Ichikawa <masami256@gmail.com
- Link to v1: https://lore.kernel.org/op-tee/20250919124217.2934718-1-jens.wiklander@linar...
drivers/tee/tee_shm.c | 8 ++++++++ 1 file changed, 8 insertions(+)
Reviewed-by: Sumit Garg sumit.garg@oss.qualcomm.com
-Sumit
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index daf6e5cfd59a..76c54e1dc98c 100644 --- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -319,6 +319,14 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags, 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;/* -- 2.43.0