CVE-2022-49802: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix null pointer dereference in ftrace_add_mod() The @ftrace_mod is allocated by kzalloc(), so both the members {prev,next} of @ftrace_mode->list are NULL, it's not a valid state to call list_del(). If kstrdup() for @ftrace_mod->{func|module} fails, it goes to @out_free tag and calls free_ftrace_mod() to destroy @ftrace_mod, then list_del() will write prev->next and next->prev, where null pointer dereference happens. BUG: kernel NULL pointer dereference, address: 0000000000000008 Oops: 0002 [#1] PREEMPT SMP NOPTI Call Trace: <TASK> ftrace_mod_callback+0x20d/0x220 ? do_filp_open+0xd9/0x140 ftrace_process_regex.isra.51+0xbf/0x130 ftrace_regex_write.isra.52.part.53+0x6e/0x90 vfs_write+0xee/0x3a0 ? __audit_filter_op+0xb1/0x100 ? auditd_test_task+0x38/0x50 ksys_write+0xa5/0xe0 do_syscall_64+0x3a/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Kernel panic - not syncing: Fatal exception So call INIT_LIST_HEAD() to initialize the list member to fix this issue.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	4.13 — 4.14.300
linux	linux_kernel	4.15 — 4.19.267
linux	linux_kernel	4.20 — 5.4.225
linux	linux_kernel	5.5 — 5.10.156
linux	linux_kernel	5.11 — 5.15.80
linux	linux_kernel	5.16 — 6.0.10
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/19ba6c8af9382c4c05dc6a0a79af3013b9a35cd0 https://git.kernel.org/stable/c/1bea037a1abb23a6729bef36a2265a4565f5ea77 https://git.kernel.org/stable/c/665b4c6648bf2b91f69b33817f4321cf4c3cafe9 https://git.kernel.org/stable/c/6a14828caddad0d989495a72af678adf60992704 https://git.kernel.org/stable/c/6e50eb4b1807017f6c2d5089064256ce2de8aef1 https://git.kernel.org/stable/c/b5bfc61f541d3f092b13dedcfe000d86eb8e133c https://git.kernel.org/stable/c/f715f31559b82e3f75ce047fa476de63d8107584

Frequently Asked Questions

What is CVE-2022-49802? +

In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix null pointer dereference in ftrace_add_mod() The @ftrace_mod is allocated by kzalloc(), so both the members {prev,next} of @ftrace_mode->list are NULL, it's not a valid state to call list_del(). If kstrdup() for @ftrace_mod->{func|module} fails, it goes to @out_free tag and calls free_ftrace_mod() to destroy @ftrace_mod, then list_del() will write prev->next and next->prev, where null pointer dereference happens. BUG: kernel NULL pointer dereference, address: 0000000000000008 Oops: 0002 [#1] PREEMPT SMP NOPTI Call Trace: <TASK> ftrace_mod_callback+0x20d/0x220 ? do_filp_open+0xd9/0x140 ftrace_process_regex.isra.51+0xbf/0x130 ftrace_regex_write.isra.52.part.53+0x6e/0x90 vfs_write+0xee/0x3a0 ? __audit_filter_op+0xb1/0x100 ? auditd_test_task+0x38/0x50 ksys_write+0xa5/0xe0 do_syscall_64+0x3a/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Kernel panic - not syncing: Fatal exception So call INIT_LIST_HEAD() to initialize the list member to fix this issue. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2022-49802? +

CVE-2022-49802 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2022-49802? +

CVE-2022-49802 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2022-49802? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2022-49802