CVE-2023-52504

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 ]

• linux linux kernel (>= 4.17 < 4.19.297) • linux linux kernel (>= 4.20 < 5.4.270) • linux linux kernel (>= 5.5 < 5.10.199) • linux linux kernel (>= 5.11 < 5.15.136) • linux linux kernel (>= 5.16 < 6.1.59) • linux linux kernel (>= 6.2 < 6.5.8) • linux linux kernel 6.6