| Summary: |
VUL-0: CVE-2024-39501: kernel: drivers: core: synchronize really_probe() and dev_uevent() |
| Product: |
[Novell Products] SUSE Security Incidents
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Reporter: |
SMASH SMASH <smash_bz> |
| Component: |
Incidents | Assignee: |
Security Team bot <security-team> |
| Status: |
NEW
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QA Contact: |
Security Team bot <security-team> |
| Severity: |
Normal
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| Priority: |
P3 - Medium
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CC: |
andrea.mattiazzo, miroslav.franc, tiwai
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| Version: |
unspecified | |
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| Target Milestone: |
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| Hardware: |
Other | |
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| OS: |
Other | |
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| URL: |
https://smash.suse.de/issue/413816/
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| Whiteboard: |
CVSSv3.1:SUSE:CVE-2024-39501:4.7:(AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H) |
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Found By:
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Security Response Team
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Services Priority:
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Business Priority:
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Blocker:
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Marketing QA Status:
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IT Deployment:
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In the Linux kernel, the following vulnerability has been resolved: drivers: core: synchronize really_probe() and dev_uevent() Synchronize the dev->driver usage in really_probe() and dev_uevent(). These can run in different threads, what can result in the following race condition for dev->driver uninitialization: Thread #1: ========== really_probe() { ... probe_failed: ... device_unbind_cleanup(dev) { ... dev->driver = NULL; // <= Failed probe sets dev->driver to NULL ... } ... } Thread #2: ========== dev_uevent() { ... if (dev->driver) // If dev->driver is NULLed from really_probe() from here on, // after above check, the system crashes add_uevent_var(env, "DRIVER=%s", dev->driver->name); ... } really_probe() holds the lock, already. So nothing needs to be done there. dev_uevent() is called with lock held, often, too. But not always. What implies that we can't add any locking in dev_uevent() itself. So fix this race by adding the lock to the non-protected path. This is the path where above race is observed: dev_uevent+0x235/0x380 uevent_show+0x10c/0x1f0 <= Add lock here dev_attr_show+0x3a/0xa0 sysfs_kf_seq_show+0x17c/0x250 kernfs_seq_show+0x7c/0x90 seq_read_iter+0x2d7/0x940 kernfs_fop_read_iter+0xc6/0x310 vfs_read+0x5bc/0x6b0 ksys_read+0xeb/0x1b0 __x64_sys_read+0x42/0x50 x64_sys_call+0x27ad/0x2d30 do_syscall_64+0xcd/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Similar cases are reported by syzkaller in https://syzkaller.appspot.com/bug?extid=ffa8143439596313a85a But these are regarding the *initialization* of dev->driver dev->driver = drv; As this switches dev->driver to non-NULL these reports can be considered to be false-positives (which should be "fixed" by this commit, as well, though). The same issue was reported and tried to be fixed back in 2015 in https://lore.kernel.org/lkml/1421259054-2574-1-git-send-email-a.sangwan@samsung.com/ already. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-39501 https://www.cve.org/CVERecord?id=CVE-2024-39501 https://git.kernel.org/stable/c/08891eeaa97c079b7f95d60b62dcf0e3ce034b69 https://git.kernel.org/stable/c/13d25e82b6d00d743c7961dcb260329f86bedf7c https://git.kernel.org/stable/c/760603e30bf19d7b4c28e9d81f18b54fa3b745ad https://git.kernel.org/stable/c/95d03d369ea647b89e950667f1c3363ea6f564e6 https://git.kernel.org/stable/c/a42b0060d6ff2f7e59290a26d5f162a3c6329b90 https://git.kernel.org/stable/c/bb3641a5831789d83a58a39ed4a928bcbece7080 https://git.kernel.org/stable/c/c0a40097f0bc81deafc15f9195d1fb54595cd6d0 https://git.kernel.org/stable/c/ec772ed7cb21b46fb132f89241682553efd0b721 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-39501.mbox