md: fix mddev uaf while iterating all_mddevs list
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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: md: fix mddev uaf while iterating all_mddevs list While iterating all_mddevs list from md_notify_reboot() and md_exit(), list_for_each_entry_safe is used, and this can race with deletint the next mddev, causing UAF: t1: spin_lock //list_for_each_entry_safe(mddev, n, ...) mddev_get(mddev1) // assume mddev2 is the next entry spin_unlock t2: //remove mddev2 ... mddev_free spin_lock list_del spin_unlock kfree(mddev2) mddev_put(mddev1) spin_lock //continue dereference mddev2->all_mddevs The old helper for_each_mddev() actually grab the reference of mddev2 while holding the lock, to prevent from being freed. This problem can be fixed the same way, however, the code will be complex. Hence switch to use list_for_each_entry, in this case mddev_put() can free the mddev1 and it's not safe as well. Refer to md_seq_show(), also factor out a helper mddev_put_locked() to fix this problem.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
Version range not reported
- Linux Linux
6.0