CVE-2020-7053

In the Linux kernel 4.14 longterm through 4.14.165 and 4.19 longterm through 4.19.96 (and 5.x before 5.2), there is a use-after-free (write) in the i915_ppgtt_close function in drivers/gpu/drm/i915/i915_gem_gtt.c, aka CID-7dc40713618c. This is related to i915_gem_context_destroy_ioctl in drivers/gpu/drm/i915/i915_gem_context.c.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00021.html
• http://packetstormsecurity.com/files/156455/Kernel-Live-Patch-Security-Notice-LSN-0063-1.html
• https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1859522
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.2
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7dc40713618c884bf07c030d1ab1f47a9dc1f310
• https://lore.kernel.org/stable/20200114183937.12224-1-tyhicks%40canonical.com
• https://security.netapp.com/advisory/ntap-20200204-0002/
• https://usn.ubuntu.com/4255-1/
• https://usn.ubuntu.com/4255-2/
• https://usn.ubuntu.com/4285-1/
• https://usn.ubuntu.com/4287-1/
• https://usn.ubuntu.com/4287-2/
• http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00021.html
• http://packetstormsecurity.com/files/156455/Kernel-Live-Patch-Security-Notice-LSN-0063-1.html
• https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1859522
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.2
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7dc40713618c884bf07c030d1ab1f47a9dc1f310
• https://lore.kernel.org/stable/20200114183937.12224-1-tyhicks%40canonical.com
• https://security.netapp.com/advisory/ntap-20200204-0002/
• https://usn.ubuntu.com/4255-1/
• https://usn.ubuntu.com/4255-2/
• https://usn.ubuntu.com/4285-1/
• https://usn.ubuntu.com/4287-1/
• https://usn.ubuntu.com/4287-2/