CVE-2022-50093

Summary

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

iommu/vt-d: avoid invalid memory access via node_online(NUMA_NO_NODE)

KASAN reports:

[ 4.668325][ T0] BUG: KASAN: wild-memory-access in dmar_parse_one_rhsa (arch/x86/include/asm/bitops.h:214 arch/x86/include/asm/bitops.h:226 include/asm-generic/bitops/instrumented-non-atomic.h:142 include/linux/nodemask.h:415 drivers/iommu/intel/dmar.c:497) [ 4.676149][ T0] Read of size 8 at addr 1fffffff85115558 by task swapper/0/0 [ 4.683454][ T0] [ 4.685638][ T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc3-00004-g0e862838f290 #1 [ 4.694331][ T0] Hardware name: Supermicro SYS-5018D-FN4T/X10SDV-8C-TLN4F, BIOS 1.1 03/02/2016 [ 4.703196][ T0] Call Trace: [ 4.706334][ T0] <TASK> [ 4.709133][ T0] ? dmar_parse_one_rhsa (arch/x86/include/asm/bitops.h:214 arch/x86/include/asm/bitops.h:226 include/asm-generic/bitops/instrumented-non-atomic.h:142 include/linux/nodemask.h:415 drivers/iommu/intel/dmar.c:497)

after converting the type of the first argument (@nr, bit number) of arch_test_bit() from long to unsigned long[0].

Under certain conditions (for example, when ACPI NUMA is disabled via command line), pxm_to_node() can return %NUMA_NO_NODE (-1). It is valid 'magic' number of NUMA node, but not valid bit number to use in bitops. node_online() eventually descends to test_bit() without checking for the input, assuming it's on caller side (which might be good for perf-critical tasks). There, -1 becomes %ULONG_MAX which leads to an insane array index when calculating bit position in memory.

For now, add an explicit check for @node being not %NUMA_NO_NODE before calling test_bit(). The actual logics didn't change here at all.

[0] https://github.com/norov/linux/commit/0e862838f290147ea9c16db852d8d494b552d38d

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/b12304984654d8e58a2b22ff94c4410906d6267f
• https://git.kernel.org/stable/c/5659efdadf04b56707d58c1b758df16d2e0eff2c
• https://git.kernel.org/stable/c/0b4c0003aeda32a600f95df53b2848da8a5aa3fa
• https://git.kernel.org/stable/c/73ce2046e04ad488cecc66757c36cbe1bdf089d4
• https://git.kernel.org/stable/c/c2304c50f4d94f56c2e326f25c9dc8cf2ba6f5fa
• https://git.kernel.org/stable/c/b0b0b77ea611e3088e9523e60860f4f41b62b235

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