accel/qaic: Treat remaining == 0 as error in find_and_map_user_pages()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: accel/qaic: Treat remaining == 0 as error in find_and_map_user_pages() Currently, if find_and_map_user_pages() takes a DMA xfer request from the user with a length field set to 0, or in a rare case, the host receives QAIC_TRANS_DMA_XFER_CONT from the device where resources->xferred_dma_size is equal to the requested transaction size, the function will return 0 before allocating an sgt or setting the fields of the dma_xfer struct. In that case, encode_addr_size_pairs() will try to access the sgt which will lead to a general protection fault. Return an EINVAL in case the user provides a zero-sized ALP, or the device requests continuation after all of the bytes have been transferred.

References

• https://git.kernel.org/stable/c/48b1d42286bfef7628b1d6c8c28d4e456c90f725
• https://git.kernel.org/stable/c/551f1dfbcb7f3e6ed07f9d6c8c1c64337fcd0ede
• https://git.kernel.org/stable/c/1ab9733d14cc9987cc5dcd1f0ad1f416e302e2e6
• https://git.kernel.org/stable/c/11f08c30a3e4157305ba692f1d44cca5fc9a8fca