Alexander Lobakin c2304c50f4 iommu/vt-d: avoid invalid memory access via node_online(NUMA_NO_NODE)
[ Upstream commit b0b0b77ea611e3088e9523e60860f4f41b62b235 ]

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] 0e862838f2

Fixes: ee34b32d8c29 ("dmar: support for parsing Remapping Hardware Static Affinity structure")
Cc: stable@vger.kernel.org # 2.6.33+
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 15:16:08 +02:00
2022-08-17 15:16:07 +02:00
2022-07-27 09:43:07 -07:00
2022-08-17 15:14:20 +02:00

Linux kernel
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There are several guides for kernel developers and users. These guides can
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There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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