Bug 2334462 (CVE-2024-56612)
| Summary: | CVE-2024-56612 kernel: mm/gup: handle NULL pages in unpin_user_pages() | ||
|---|---|---|---|
| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | dfreiber, drow, jburrell, vkumar |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
In the Linux kernel, the following vulnerability has been resolved: mm/gup: handle NULL pages in unpin_user_pages() The recent addition of "pofs" (pages or folios) handling to gup has a flaw: it assumes that unpin_user_pages() handles NULL pages in the pages** array. That's not the case, as I discovered when I ran on a new configuration on my test machine. Fix this by skipping NULL pages in unpin_user_pages(), just like unpin_folios() already does. Details: when booting on x86 with "numa=fake=2 movablecore=4G" on Linux 6.12, and running this: tools/testing/selftests/mm/gup_longterm ...I get the following crash: BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:sanity_check_pinned_pages+0x3a/0x2d0 ... Call Trace: <TASK> ? __die_body+0x66/0xb0 ? page_fault_oops+0x30c/0x3b0 ? do_user_addr_fault+0x6c3/0x720 ? irqentry_enter+0x34/0x60 ? exc_page_fault+0x68/0x100 ? asm_exc_page_fault+0x22/0x30 ? sanity_check_pinned_pages+0x3a/0x2d0 unpin_user_pages+0x24/0xe0 check_and_migrate_movable_pages_or_folios+0x455/0x4b0 __gup_longterm_locked+0x3bf/0x820 ? mmap_read_lock_killable+0x12/0x50 ? __pfx_mmap_read_lock_killable+0x10/0x10 pin_user_pages+0x66/0xa0 gup_test_ioctl+0x358/0xb20 __se_sys_ioctl+0x6b/0xc0 do_syscall_64+0x7b/0x150 entry_SYSCALL_64_after_hwframe+0x76/0x7e