CVE-2022-49990High· 7.8▾ TwilightIn the Linux kernel, the following vulnerability has been resolved: s390: fix double free of GS and RI CBs on fork() failure The pointers for guarded storage and runtime instrumentation control blocks are stored in the thread_struct of…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 42.9 · likelihood 0.1 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Oct 15.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
0.3%
7.8 → 5.5
high → medium
0.3% → 0.3%
5.5 → 7.8
medium → high
In the Linux kernel, the following vulnerability has been resolved:
s390: fix double free of GS and RI CBs on fork() failure
The pointers for guarded storage and runtime instrumentation control blocks are stored in the thread_struct of the associated task. These pointers are initially copied on fork() via arch_dup_task_struct() and then cleared via copy_thread() before fork() returns. If fork() happens to fail after the initial task dup and before copy_thread(), the newly allocated task and associated thread_struct memory are freed via free_task() -> arch_release_task_struct(). This results in a double free of the guarded storage and runtime info structs because the fields in the failed task still refer to memory associated with the source task.
This problem can manifest as a BUG_ON() in set_freepointer() (with CONFIG_SLAB_FREELIST_HARDENED enabled) or KASAN splat (if enabled) when running trinity syscall fuzz tests on s390x. To avoid this problem, clear the associated pointer fields in arch_dup_task_struct() immediately after the new task is copied. Note that the RI flag is still cleared in copy_thread() because it resides in thread stack memory and that is where stack info is copied.
linux_kernel >= 4.4.105, < 4.5linux_kernel >= 4.9.68, < 4.10linux_kernel >= 4.14.5, < 4.19.257linux_kernel >= 4.20, < 5.4.212linux_kernel >= 5.5, < 5.10.140linux_kernel >= 5.11, < 5.15.64linux_kernel >= 5.16, < 5.19.6linux_kernel = 6.0Upgrade past the affected range:
linux_kernel 5.19.6Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
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