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In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu: Use the correct type in nvidia_smmu_context_fault() This was missed because of the function pointer indirection. nvidia_smmu_context_fault() is also installed as a irq function, and the 'void *' was changed to a struct arm_smmu_domain. Since the iommu_domain is embedded at a non-zero offset this causes nvidia_smmu_context_fault() to miscompute the offset. Fixup the types. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000120 Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 user pgtable: 4k pages, 48-bit VAs, pgdp=0000000107c9f000 [0000000000000120] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 0000000096000004 [#1] SMP Modules linked in: CPU: 1 PID: 47 Comm: kworker/u25:0 Not tainted 6.9.0-0.rc7.58.eln136.aarch64 #1 Hardware name: Unknown NVIDIA Jetson Orin NX/NVIDIA Jetson Orin NX, BIOS 3.1-32827747 03/19/2023 Workqueue: events_unbound deferred_probe_work_func pstate: 604000c9 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : nvidia_smmu_context_fault+0x1c/0x158 lr : __free_irq+0x1d4/0x2e8 sp : ffff80008044b6f0 x29: ffff80008044b6f0 x28: ffff000080a60b18 x27: ffffd32b5172e970 x26: 0000000000000000 x25: ffff0000802f5aac x24: ffff0000802f5a30 x23: ffff0000802f5b60 x22: 0000000000000057 x21: 0000000000000000 x20: ffff0000802f5a00 x19: ffff000087d4cd80 x18: ffffffffffffffff x17: 6234362066666666 x16: 6630303078302d30 x15: ffff00008156d888 x14: 0000000000000000 x13: ffff0000801db910 x12: ffff00008156d6d0 x11: 0000000000000003 x10: ffff0000801db918 x9 : ffffd32b50f94d9c x8 : 1fffe0001032fda1 x7 : ffff00008197ed00 x6 : 000000000000000f x5 : 000000000000010e x4 : 000000000000010e x3 : 0000000000000000 x2 : ffffd32b51720cd8 x1 : ffff000087e6f700 x0 : 0000000000000057 Call trace: nvidia_smmu_context_fault+0x1c/0x158 __free_irq+0x1d4/0x2e8 free_irq+0x3c/0x80 devm_free_irq+0x64/0xa8 arm_smmu_domain_free+0xc4/0x158 iommu_domain_free+0x44/0xa0 iommu_deinit_device+0xd0/0xf8 __iommu_group_remove_device+0xcc/0xe0 iommu_bus_notifier+0x64/0xa8 notifier_call_chain+0x78/0x148 blocking_notifier_call_chain+0x4c/0x90 bus_notify+0x44/0x70 device_del+0x264/0x3e8 pci_remove_bus_device+0x84/0x120 pci_remove_root_bus+0x5c/0xc0 dw_pcie_host_deinit+0x38/0xe0 tegra_pcie_config_rp+0xc0/0x1f0 tegra_pcie_dw_probe+0x34c/0x700 platform_probe+0x70/0xe8 really_probe+0xc8/0x3a0 __driver_probe_device+0x84/0x160 driver_probe_device+0x44/0x130 __device_attach_driver+0xc4/0x170 bus_for_each_drv+0x90/0x100 __device_attach+0xa8/0x1c8 device_initial_probe+0x1c/0x30 bus_probe_device+0xb0/0xc0 deferred_probe_work_func+0xbc/0x120 process_one_work+0x194/0x490 worker_thread+0x284/0x3b0 kthread+0xf4/0x108 ret_from_fork+0x10/0x20 Code: a9b97bfd 910003fd a9025bf5 f85a0035 (b94122a1)
CVSS 3.1 Base Score 5.5. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
While there are no complete fixes aside from conscientious programming, the following steps will go a long way to ensure that NULL pointer dereferences do not occur.
}
/* make use of pointer1 *//* ... */If you are working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the if statement; and unlock when it has finished.
This example takes an IP address from a user, verifies that it is well formed and then looks up the hostname and copies it into a buffer.
}
strcpy(hostname, hp->h_name);/*routine that ensures user_supplied_addr is in the right format for conversion */If an attacker provides an address that appears to be well-formed, but the address does not resolve to a hostname, then the call to gethostbyaddr() will return NULL. Since the code does not check the return value from gethostbyaddr (CWE-252), a NULL pointer dereference would then occur in the call to strcpy().
Note that this example is also vulnerable to a buffer overflow (see CWE-119).
In the following code, the programmer assumes that the system always has a property named "cmd" defined. If an attacker can control the program's environment so that "cmd" is not defined, the program throws a NULL pointer exception when it attempts to call the trim() method.
cmd = cmd.trim();This application has registered to handle a URL when sent an intent:
}......
}
}int length = URL.length();...The application assumes the URL will always be included in the intent. When the URL is not present, the call to getStringExtra() will return null, thus causing a null pointer exception when length() is called.
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