CVE-2024-26656CVE-2024-26656

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: fix use-after-free bug The bug can be triggered by sending a single amdgpu_gem_userptr_ioctl to the AMDGPU DRM driver on any ASICs with an invalid address and size. The bug was reported by Joonkyo Jung <joonkyoj@yonsei.ac.kr>. For example the following code: static void Syzkaller1(int fd) { struct drm_amdgpu_gem_userptr arg; int ret; arg.addr = 0xffffffffffff0000; arg.size = 0x80000000; /*2 Gb*/ arg.flags = 0x7; ret = drmIoctl(fd, 0xc1186451/*amdgpu_gem_userptr_ioctl*/, &arg); } Due to the address and size are not valid there is a failure in amdgpu_hmm_register->mmu_interval_notifier_insert->__mmu_interval_notifier_insert-> check_shl_overflow, but we even the amdgpu_hmm_register failure we still call amdgpu_hmm_unregister into amdgpu_gem_object_free which causes access to a bad address. The following stack is below when the issue is reproduced when Kazan is enabled: [ +0.000014] Hardware name: