CVE-2023-52909
Linux Kernel NFSidor Server File System Handling Vulnerability
Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix handling of cached open files in nfsd4_open codepath Commit fb70bf124b05 ("NFSD: Instantiate a struct file when creating a regular NFSv4 file") added the ability to cache an open fd over a compound. There are a couple of problems with the way this currently works: It's racy, as a newly-created nfsd_file can end up with its PENDING bit cleared while the nf is hashed, and the nf_file pointer is still zeroed out. Other tasks can find it in this state and they expect to see a valid nf_file, and can oops if nf_file is NULL. Also, there is no guarantee that we'll end up creating a new nfsd_file if one is already in the hash. If an extant entry is in the hash with a valid nf_file, nfs4_get_vfs_file will clobber its nf_file pointer with the value of op_file and the old nf_file will leak. Fix both issues by making a new nfsd_file_acquirei_opened variant that takes an optional file pointer. If one is present when this is called, we'll take a new reference to it instead of trying to open the file. If the nfsd_file already has a valid nf_file, we'll just ignore the optional file and pass the nfsd_file back as-is. Also rework the tracepoints a bit to allow for an "opened" variant and don't try to avoid counting acquisitions in the case where we already have a cached open file.
INFO
Published Date :
Aug. 21, 2024, 7:15 a.m.
Last Modified :
Sept. 12, 2024, 2:52 p.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
3.6
Exploitability Score :
1.0
References to Advisories, Solutions, and Tools
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information, practical solutions, and valuable tools related to
CVE-2023-52909
.
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The following list is the news that have been mention
CVE-2023-52909
vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2023-52909
vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Sep. 12, 2024
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H Changed Reference Type https://git.kernel.org/stable/c/0b3a551fa58b4da941efeb209b3770868e2eddd7 No Types Assigned https://git.kernel.org/stable/c/0b3a551fa58b4da941efeb209b3770868e2eddd7 Patch Changed Reference Type https://git.kernel.org/stable/c/0b778361998d6c6356b8d2fc7ddf025fb3224654 No Types Assigned https://git.kernel.org/stable/c/0b778361998d6c6356b8d2fc7ddf025fb3224654 Patch Changed Reference Type https://git.kernel.org/stable/c/45c08a752982116f3287afcd1bd9c50f4fab0c28 No Types Assigned https://git.kernel.org/stable/c/45c08a752982116f3287afcd1bd9c50f4fab0c28 Patch Changed Reference Type https://git.kernel.org/stable/c/973acfdfe90c8a4e58ade97ff0653a498531ff2e No Types Assigned https://git.kernel.org/stable/c/973acfdfe90c8a4e58ade97ff0653a498531ff2e Patch Added CWE NIST CWE-476 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.19 up to (excluding) 6.1.7 *cpe:2.3:o:linux:linux_kernel:6.2:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.2:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.2:rc3:*:*:*:*:*:* -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 21, 2024
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: nfsd: fix handling of cached open files in nfsd4_open codepath Commit fb70bf124b05 ("NFSD: Instantiate a struct file when creating a regular NFSv4 file") added the ability to cache an open fd over a compound. There are a couple of problems with the way this currently works: It's racy, as a newly-created nfsd_file can end up with its PENDING bit cleared while the nf is hashed, and the nf_file pointer is still zeroed out. Other tasks can find it in this state and they expect to see a valid nf_file, and can oops if nf_file is NULL. Also, there is no guarantee that we'll end up creating a new nfsd_file if one is already in the hash. If an extant entry is in the hash with a valid nf_file, nfs4_get_vfs_file will clobber its nf_file pointer with the value of op_file and the old nf_file will leak. Fix both issues by making a new nfsd_file_acquirei_opened variant that takes an optional file pointer. If one is present when this is called, we'll take a new reference to it instead of trying to open the file. If the nfsd_file already has a valid nf_file, we'll just ignore the optional file and pass the nfsd_file back as-is. Also rework the tracepoints a bit to allow for an "opened" variant and don't try to avoid counting acquisitions in the case where we already have a cached open file. Added Reference kernel.org https://git.kernel.org/stable/c/45c08a752982116f3287afcd1bd9c50f4fab0c28 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/0b778361998d6c6356b8d2fc7ddf025fb3224654 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/973acfdfe90c8a4e58ade97ff0653a498531ff2e [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/0b3a551fa58b4da941efeb209b3770868e2eddd7 [No types assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2023-52909
is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2023-52909
weaknesses.