CVE-2023-52504

Summary

In the Linux kernel, the following vulnerability has been resolved:

x86/alternatives: Disable KASAN in apply_alternatives()

Fei has reported that KASAN triggers during apply_alternatives() on a 5-level paging machine:

BUG: KASAN: out-of-bounds in rcu_is_watching()
Read of size 4 at addr ff110003ee6419a0 by task swapper/0/0
...
__asan_load4()
rcu_is_watching()
trace_hardirqs_on()
text_poke_early()
apply_alternatives()
...

On machines with 5-level paging, cpu_feature_enabled(X86_FEATURE_LA57) gets patched. It includes KASAN code, where KASAN_SHADOW_START depends on __VIRTUAL_MASK_SHIFT, which is defined with cpu_feature_enabled().

KASAN gets confused when apply_alternatives() patches the KASAN_SHADOW_START users. A test patch that makes KASAN_SHADOW_START static, by replacing __VIRTUAL_MASK_SHIFT with 56, works around the issue.

Fix it for real by disabling KASAN while the kernel is patching alternatives.

[ mingo: updated the changelog ]

Affected Software

VendorProductVersion RangeStatus
LinuxLinux6657fca06e3ffab8d0b3f9d8b397f5ee498952d7 < 3719d3c36aa853d5a2401af9f8d6b116c91ad5aeaffected
LinuxLinux6657fca06e3ffab8d0b3f9d8b397f5ee498952d7 < 3770c38cd6a60494da29ac2da73ff8156440a2d1affected
LinuxLinux6657fca06e3ffab8d0b3f9d8b397f5ee498952d7 < 6788b10620ca6e98575d1e06e72a8974aad7657eaffected
LinuxLinux6657fca06e3ffab8d0b3f9d8b397f5ee498952d7 < ecba5afe86f30605eb9dfb7f265a8de0218d4cfcaffected
LinuxLinux6657fca06e3ffab8d0b3f9d8b397f5ee498952d7 < 5b784489c8158518bf7a466bb3cc045b0fb66b4baffected
LinuxLinux6657fca06e3ffab8d0b3f9d8b397f5ee498952d7 < cd287cc208dfe6bd6da98e7f88e723209242c9b4affected
LinuxLinux6657fca06e3ffab8d0b3f9d8b397f5ee498952d7 < d35652a5fc9944784f6f50a5c979518ff8dacf61affected
LinuxLinux4.17affected
LinuxLinux0 < 4.17unaffected
LinuxLinux4.19.297 <= 4.19.*unaffected
LinuxLinux5.4.270 <= 5.4.*unaffected
LinuxLinux5.10.199 <= 5.10.*unaffected
LinuxLinux5.15.136 <= 5.15.*unaffected
LinuxLinux6.1.59 <= 6.1.*unaffected
LinuxLinux6.5.8 <= 6.5.*unaffected
LinuxLinux6.6 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References