CVE-2022-50069
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-06-18

Last updated on: 2025-11-17

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: BPF: Fix potential bad pointer dereference in bpf_sys_bpf() The bpf_sys_bpf() helper function allows an eBPF program to load another eBPF program from within the kernel. In this case the argument union bpf_attr pointer (as well as the insns and license pointers inside) is a kernel address instead of a userspace address (which is the case of a usual bpf() syscall). To make the memory copying process in the syscall work in both cases, bpfptr_t was introduced to wrap around the pointer and distinguish its origin. Specifically, when copying memory contents from a bpfptr_t, a copy_from_user() is performed in case of a userspace address and a memcpy() is performed for a kernel address. This can lead to problems because the in-kernel pointer is never checked for validity. The problem happens when an eBPF syscall program tries to call bpf_sys_bpf() to load a program but provides a bad insns pointer -- say 0xdeadbeef -- in the bpf_attr union. The helper calls __sys_bpf() which would then call bpf_prog_load() to load the program. bpf_prog_load() is responsible for copying the eBPF instructions to the newly allocated memory for the program; it creates a kernel bpfptr_t for insns and invokes copy_from_bpfptr(). Internally, all bpfptr_t operations are backed by the corresponding sockptr_t operations, which performs direct memcpy() on kernel pointers for copy_from/strncpy_from operations. Therefore, the code is always happy to dereference the bad pointer to trigger a un-handle-able page fault and in turn an oops. However, this is not supposed to happen because at that point the eBPF program is already verified and should not cause a memory error. Sample KASAN trace: [ 25.685056][ T228] ================================================================== [ 25.685680][ T228] BUG: KASAN: user-memory-access in copy_from_bpfptr+0x21/0x30 [ 25.686210][ T228] Read of size 80 at addr 00000000deadbeef by task poc/228 [ 25.686732][ T228] [ 25.686893][ T228] CPU: 3 PID: 228 Comm: poc Not tainted 5.19.0-rc7 #7 [ 25.687375][ T228] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS d55cb5a 04/01/2014 [ 25.687991][ T228] Call Trace: [ 25.688223][ T228] <TASK> [ 25.688429][ T228] dump_stack_lvl+0x73/0x9e [ 25.688747][ T228] print_report+0xea/0x200 [ 25.689061][ T228] ? copy_from_bpfptr+0x21/0x30 [ 25.689401][ T228] ? _printk+0x54/0x6e [ 25.689693][ T228] ? _raw_spin_lock_irqsave+0x70/0xd0 [ 25.690071][ T228] ? copy_from_bpfptr+0x21/0x30 [ 25.690412][ T228] kasan_report+0xb5/0xe0 [ 25.690716][ T228] ? copy_from_bpfptr+0x21/0x30 [ 25.691059][ T228] kasan_check_range+0x2bd/0x2e0 [ 25.691405][ T228] ? copy_from_bpfptr+0x21/0x30 [ 25.691734][ T228] memcpy+0x25/0x60 [ 25.692000][ T228] copy_from_bpfptr+0x21/0x30 [ 25.692328][ T228] bpf_prog_load+0x604/0x9e0 [ 25.692653][ T228] ? cap_capable+0xb4/0xe0 [ 25.692956][ T228] ? security_capable+0x4f/0x70 [ 25.693324][ T228] __sys_bpf+0x3af/0x580 [ 25.693635][ T228] bpf_sys_bpf+0x45/0x240 [ 25.693937][ T228] bpf_prog_f0ec79a5a3caca46_bpf_func1+0xa2/0xbd [ 25.694394][ T228] bpf_prog_run_pin_on_cpu+0x2f/0xb0 [ 25.694756][ T228] bpf_prog_test_run_syscall+0x146/0x1c0 [ 25.695144][ T228] bpf_prog_test_run+0x172/0x190 [ 25.695487][ T228] __sys_bpf+0x2c5/0x580 [ 25.695776][ T228] __x64_sys_bpf+0x3a/0x50 [ 25.696084][ T228] do_syscall_64+0x60/0x90 [ 25.696393][ T228] ? fpregs_assert_state_consistent+0x50/0x60 [ 25.696815][ T228] ? exit_to_user_mode_prepare+0x36/0xa0 [ 25.697202][ T228] ? syscall_exit_to_user_mode+0x20/0x40 [ 25.697586][ T228] ? do_syscall_64+0x6e/0x90 [ 25.697899][ T228] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 25.698312][ T228] RIP: 0033:0x7f6d543fb759 [ 25.698624][ T228] Code: 08 5b 89 e8 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d ---truncated---
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Meta Information
Published
2025-06-18
Last Modified
2025-11-17
Generated
2026-05-07
AI Q&A
2025-06-18
EPSS Evaluated
2026-05-05
NVD
CVE-2022-50069
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in the Linux kernel's bpf_sys_bpf() function, which allows an eBPF program to load another eBPF program from within the kernel. The issue arises because the function accepts a pointer that can be either a userspace or kernel address, but it does not properly validate kernel pointers. If a bad kernel pointer (e.g., 0xdeadbeef) is provided, the kernel attempts to dereference it without checking validity, leading to a kernel crash (oops) due to an un-handleable page fault. This happens despite the eBPF program being verified, which should normally prevent such memory errors.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash or become unstable when an eBPF program attempts to load another program using a bad kernel pointer. This can lead to denial of service (DoS) conditions, where the system becomes unresponsive or requires a reboot, potentially impacting availability and reliability of services running on the affected system.


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