]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
tee: add overflow check in register_shm_helper()
authorJens Wiklander <jens.wiklander@linaro.org>
Thu, 18 Aug 2022 11:08:59 +0000 (13:08 +0200)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 18 Aug 2022 16:20:27 +0000 (09:20 -0700)
commit573ae4f13f630d6660008f1974c0a8a29c30e18a
tree522a9f2f62424eeeef9b85bfe4188b9e36100ce2
parent3b06a2755758937add738545ba4a544fc5a1c56d
tee: add overflow check in register_shm_helper()

With special lengths supplied by user space, register_shm_helper() has
an integer overflow when calculating the number of pages covered by a
supplied user space memory region.

This causes internal_get_user_pages_fast() a helper function of
pin_user_pages_fast() to do a NULL pointer dereference:

  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
  Modules linked in:
  CPU: 1 PID: 173 Comm: optee_example_a Not tainted 5.19.0 #11
  Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
  pc : internal_get_user_pages_fast+0x474/0xa80
  Call trace:
   internal_get_user_pages_fast+0x474/0xa80
   pin_user_pages_fast+0x24/0x4c
   register_shm_helper+0x194/0x330
   tee_shm_register_user_buf+0x78/0x120
   tee_ioctl+0xd0/0x11a0
   __arm64_sys_ioctl+0xa8/0xec
   invoke_syscall+0x48/0x114

Fix this by adding an an explicit call to access_ok() in
tee_shm_register_user_buf() to catch an invalid user space address
early.

Fixes: 033ddf12bcf5 ("tee: add register user memory")
Cc: stable@vger.kernel.org
Reported-by: Nimish Mishra <neelam.nimish@gmail.com>
Reported-by: Anirban Chakraborty <ch.anirban00727@gmail.com>
Reported-by: Debdeep Mukhopadhyay <debdeep.mukhopadhyay@gmail.com>
Suggested-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/tee/tee_shm.c