CVE-2022-50277
MediumIn the Linux kernel, the following vulnerability has been resolved: ext4: don't allow journal inode to have encrypt flag Mounting a filesystem whose journal inode has the encrypt flag causes a NULL dereference in fscrypt_limit_io_blocks() when the 'inlinecrypt' mount option is used. The problem is that when jbd2_journal_init_inode() calls bmap(), it eventually finds its way into ext4_iomap_begin(), which calls fscrypt_limit_io_blocks(). fscrypt_limit_io_blocks() requires that if the inode is encrypted, then its encryption key must already be set up. That's not the case here, since the journal inode is never "opened" like a normal file would be. Hence the crash. A reproducer is: mkfs.ext4 -F /dev/vdb debugfs -w /dev/vdb -R "set_inode_field <8> flags 0x80808" mount /dev/vdb /mnt -o inlinecrypt To fix this, make ext4 consider journal inodes with the encrypt flag to be invalid. (Note, maybe other flags should be rejected on the journal inode too. For now, this is just the minimal fix for the above issue.) I've marked this as fixing the commit that introduced the call to fscrypt_limit_io_blocks(), since that's what made an actual crash start being possible. But this fix could be applied to any version of ext4 that supports the encrypt feature.
CVSS 3.1 score
5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness type
CWE-476CVE-2022-50277 is a NULL Pointer Dereference vulnerability
What is NULL Pointer Dereference?
The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. Learn more on MITRE CWE
Affected versions
Linux kernel versions
5.18
and later are affected. Fixed in
6.0.18,
6.1.4,
6.2
and their respective stable series.
References
The following references provide additional information about CVE-2022-50277 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/105c78e12468413e426625831faa7db4284e1fec
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PatchKernel patch commithttps://git.kernel.org/stable/c/1f7a6626f611aa06d7907aa45b484708dd5ac8bc
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PatchKernel patch commithttps://git.kernel.org/stable/c/bcc5057e1781a3ee889225480d995c3b5cbde555
Frequently asked questions
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What is CVE-2022-50277?
CVE-2022-50277 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a NULL Pointer Dereference flaw (CWE-476) . It affects Linux kernel versions from 5.18 onward and has been patched in 6.0.18, 6.1.4 and 6.2. CVE-2022-50277 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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What is the CVSS score for CVE-2022-50277?
CVE-2022-50277 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. -
Is there a patch available for CVE-2022-50277?
Yes — CVE-2022-50277 has been patched. Fixed versions include 6.0.18, 6.1.4 and 6.2. If you are running Linux kernel 5.18 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2022-50277 actively exploited?
No — CVE-2022-50277 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
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What is NULL Pointer Dereference (CWE-476)?
The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. View CWE-476 on MITRE CWE →