In the Linux kernel, the following vulnerability has been resolved:
gfs2: Validate i_depth for exhash directories
A fuzzer test introduced corruption that ends up with a depth of 0 in
dir_e_read(), causing an undefined shift by 32 at:
index = hash >> (32 - dip->i_depth);
As calculated in an open-coded way in dir_make_exhash(), the minimum
depth for an exhash directory is ilog2(sdp->sd_hash_ptrs) and 0 is
invalid as sdp->sd_hash_ptrs is fixed as sdp->bsize / 16 at mount time.
So we can avoid the undefined behaviour by checking for depth values
lower than the minimum in gfs2_dinode_in(). Values greater than the
maximum are already being checked for there.
Also switch the calculation in dir_make_exhash() to use ilog2() to
clarify how the depth is calculated.
Tested with the syzkaller repro.c and xfstests '-g quick'.
gfs2: Validate i_depth for exhash directories
A fuzzer test introduced corruption that ends up with a depth of 0 in
dir_e_read(), causing an undefined shift by 32 at:
index = hash >> (32 - dip->i_depth);
As calculated in an open-coded way in dir_make_exhash(), the minimum
depth for an exhash directory is ilog2(sdp->sd_hash_ptrs) and 0 is
invalid as sdp->sd_hash_ptrs is fixed as sdp->bsize / 16 at mount time.
So we can avoid the undefined behaviour by checking for depth values
lower than the minimum in gfs2_dinode_in(). Values greater than the
maximum are already being checked for there.
Also switch the calculation in dir_make_exhash() to use ilog2() to
clarify how the depth is calculated.
Tested with the syzkaller repro.c and xfstests '-g quick'.
Metrics
Affected Vendors & Products
References
History
Fri, 05 Sep 2025 14:15:00 +0000
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Linux
Linux linux Kernel |
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Vendors & Products |
Linux
Linux linux Kernel |
Fri, 05 Sep 2025 00:15:00 +0000
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References |
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Metrics |
threat_severity
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cvssV3_1
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Thu, 04 Sep 2025 15:45:00 +0000
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Description | In the Linux kernel, the following vulnerability has been resolved: gfs2: Validate i_depth for exhash directories A fuzzer test introduced corruption that ends up with a depth of 0 in dir_e_read(), causing an undefined shift by 32 at: index = hash >> (32 - dip->i_depth); As calculated in an open-coded way in dir_make_exhash(), the minimum depth for an exhash directory is ilog2(sdp->sd_hash_ptrs) and 0 is invalid as sdp->sd_hash_ptrs is fixed as sdp->bsize / 16 at mount time. So we can avoid the undefined behaviour by checking for depth values lower than the minimum in gfs2_dinode_in(). Values greater than the maximum are already being checked for there. Also switch the calculation in dir_make_exhash() to use ilog2() to clarify how the depth is calculated. Tested with the syzkaller repro.c and xfstests '-g quick'. | |
Title | gfs2: Validate i_depth for exhash directories | |
References |
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-09-04T15:33:00.629Z
Reserved: 2025-04-16T04:51:24.033Z
Link: CVE-2025-38710

No data.

Status : Awaiting Analysis
Published: 2025-09-04T16:15:40.137
Modified: 2025-09-05T17:47:24.833
Link: CVE-2025-38710


Updated: 2025-09-05T14:02:36Z