On Mon, Aug 22, 2022 at 12:01 PM Greg KH gregkh@linuxfoundation.org wrote:
On Mon, Aug 22, 2022 at 11:59:17AM +0200, Greg KH wrote:
On Mon, Aug 22, 2022 at 11:26:21AM +0200, Jens Wiklander wrote:
commit 573ae4f13f630d6660008f1974c0a8a29c30e18a upstream.
With special lengths supplied by user space, tee_shm_register() has an integer overflow when calculating the number of pages covered by a supplied user space memory region.
This may cause pin_user_pages_fast() to do a NULL pointer dereference.
Fix this by adding an an explicit call to access_ok() in tee_ioctl_shm_register() to catch an invalid user space address early.
Fixes: 033ddf12bcf5 ("tee: add register user memory") Cc: stable@vger.kernel.org # 5.4 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: Linus Torvalds torvalds@linux-foundation.org [JW: backport to stable-5.4 + update commit message]
Will this also work for 4.19?
Nope, it breaks the build on 4.19.y, needs a different backport there:
Yeah, I'm just about to post a 4.19.y backport too.
Cheers, Jens
CC [M] drivers/tee/tee_core.o drivers/tee/tee_core.c: In function ‘tee_ioctl_shm_register’: drivers/tee/tee_core.c:178:76: error: macro "access_ok" requires 3 arguments, but only 2 given 178 | if (!access_ok((void __user *)(unsigned long)data.addr, data.length)) | ^ In file included from ./include/linux/uaccess.h:14, from drivers/tee/tee_core.c:24: ./arch/x86/include/asm/uaccess.h:98: note: macro "access_ok" defined here 98 | #define access_ok(type, addr, size) \ | drivers/tee/tee_core.c:178:14: error: ‘access_ok’ undeclared (first use in this function) 178 | if (!access_ok((void __user *)(unsigned long)data.addr, data.length)) | ^~~~~~~~~