CVE-2022-50080

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> tee: add overflow check in register_shm_helper()<br /> <br /> With special lengths supplied by user space, register_shm_helper() has<br /> an integer overflow when calculating the number of pages covered by a<br /> supplied user space memory region.<br /> <br /> This causes internal_get_user_pages_fast() a helper function of<br /> pin_user_pages_fast() to do a NULL pointer dereference:<br /> <br /> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010<br /> Modules linked in:<br /> CPU: 1 PID: 173 Comm: optee_example_a Not tainted 5.19.0 #11<br /> Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015<br /> pc : internal_get_user_pages_fast+0x474/0xa80<br /> Call trace:<br /> internal_get_user_pages_fast+0x474/0xa80<br /> pin_user_pages_fast+0x24/0x4c<br /> register_shm_helper+0x194/0x330<br /> tee_shm_register_user_buf+0x78/0x120<br /> tee_ioctl+0xd0/0x11a0<br /> __arm64_sys_ioctl+0xa8/0xec<br /> invoke_syscall+0x48/0x114<br /> <br /> Fix this by adding an an explicit call to access_ok() in<br /> tee_shm_register_user_buf() to catch an invalid user space address<br /> early.