-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43188
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not propagate page array emplacement errors as batch errors
When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.
However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.
Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.
For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.
-
CVE-2026-43187
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
xfs: delete attr leaf freemap entries when empty
Back in commit 2a2b5932db6758 ("xfs: fix attr leaf header freemap.size
underflow"), Brian Foster observed that it's possible for a small
freemap at the end of the end of the xattr entries array to experience
a size underflow when subtracting the space consumed by an expansion of
the entries array. There are only three freemap entries, which means
that it is not a complete index of all free space in the leaf block.
This code can leave behind a zero-length freemap entry with a nonzero
base. Subsequent setxattr operations can increase the base up to the
point that it overlaps with another freemap entry. This isn't in and of
itself a problem because the code in _leaf_add that finds free space
ignores any freemap entry with zero size.
However, there's another bug in the freemap update code in _leaf_add,
which is that it fails to update a freemap entry that begins midway
through the xattr entry that was just appended to the array. That can
result in the freemap containing two entries with the same base but
different sizes (0 for the "pushed-up" entry, nonzero for the entry
that's actually tracking free space). A subsequent _leaf_add can then
allocate xattr namevalue entries on top of the entries array, leading to
data loss. But fixing that is for later.
For now, eliminate the possibility of confusion by zeroing out the base
of any freemap entry that has zero size. Because the freemap is not
intended to be a complete index of free space, a subsequent failure to
find any free space for a new xattr will trigger block compaction, which
regenerates the freemap.
It looks like this bug has been in the codebase for quite a long time.
-
CVE-2026-43187
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
xfs: delete attr leaf freemap entries when empty
Back in commit 2a2b5932db6758 ("xfs: fix attr leaf header freemap.size
underflow"), Brian Foster observed that it's possible for a small
freemap at the end of the end of the xattr entries array to experience
a size underflow when subtracting the space consumed by an expansion of
the entries array. There are only three freemap entries, which means
that it is not a complete index of all free space in the leaf block.
This code can leave behind a zero-length freemap entry with a nonzero
base. Subsequent setxattr operations can increase the base up to the
point that it overlaps with another freemap entry. This isn't in and of
itself a problem because the code in _leaf_add that finds free space
ignores any freemap entry with zero size.
However, there's another bug in the freemap update code in _leaf_add,
which is that it fails to update a freemap entry that begins midway
through the xattr entry that was just appended to the array. That can
result in the freemap containing two entries with the same base but
different sizes (0 for the "pushed-up" entry, nonzero for the entry
that's actually tracking free space). A subsequent _leaf_add can then
allocate xattr namevalue entries on top of the entries array, leading to
data loss. But fixing that is for later.
For now, eliminate the possibility of confusion by zeroing out the base
of any freemap entry that has zero size. Because the freemap is not
intended to be a complete index of free space, a subsequent failure to
find any free space for a new xattr will trigger block compaction, which
regenerates the freemap.
It looks like this bug has been in the codebase for quite a long time.
-
CVE-2026-43187
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
xfs: delete attr leaf freemap entries when empty
Back in commit 2a2b5932db6758 ("xfs: fix attr leaf header freemap.size
underflow"), Brian Foster observed that it's possible for a small
freemap at the end of the end of the xattr entries array to experience
a size underflow when subtracting the space consumed by an expansion of
the entries array. There are only three freemap entries, which means
that it is not a complete index of all free space in the leaf block.
This code can leave behind a zero-length freemap entry with a nonzero
base. Subsequent setxattr operations can increase the base up to the
point that it overlaps with another freemap entry. This isn't in and of
itself a problem because the code in _leaf_add that finds free space
ignores any freemap entry with zero size.
However, there's another bug in the freemap update code in _leaf_add,
which is that it fails to update a freemap entry that begins midway
through the xattr entry that was just appended to the array. That can
result in the freemap containing two entries with the same base but
different sizes (0 for the "pushed-up" entry, nonzero for the entry
that's actually tracking free space). A subsequent _leaf_add can then
allocate xattr namevalue entries on top of the entries array, leading to
data loss. But fixing that is for later.
For now, eliminate the possibility of confusion by zeroing out the base
of any freemap entry that has zero size. Because the freemap is not
intended to be a complete index of free space, a subsequent failure to
find any free space for a new xattr will trigger block compaction, which
regenerates the freemap.
It looks like this bug has been in the codebase for quite a long time.
-
CVE-2026-43187
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
xfs: delete attr leaf freemap entries when empty
Back in commit 2a2b5932db6758 ("xfs: fix attr leaf header freemap.size
underflow"), Brian Foster observed that it's possible for a small
freemap at the end of the end of the xattr entries array to experience
a size underflow when subtracting the space consumed by an expansion of
the entries array. There are only three freemap entries, which means
that it is not a complete index of all free space in the leaf block.
This code can leave behind a zero-length freemap entry with a nonzero
base. Subsequent setxattr operations can increase the base up to the
point that it overlaps with another freemap entry. This isn't in and of
itself a problem because the code in _leaf_add that finds free space
ignores any freemap entry with zero size.
However, there's another bug in the freemap update code in _leaf_add,
which is that it fails to update a freemap entry that begins midway
through the xattr entry that was just appended to the array. That can
result in the freemap containing two entries with the same base but
different sizes (0 for the "pushed-up" entry, nonzero for the entry
that's actually tracking free space). A subsequent _leaf_add can then
allocate xattr namevalue entries on top of the entries array, leading to
data loss. But fixing that is for later.
For now, eliminate the possibility of confusion by zeroing out the base
of any freemap entry that has zero size. Because the freemap is not
intended to be a complete index of free space, a subsequent failure to
find any free space for a new xattr will trigger block compaction, which
regenerates the freemap.
It looks like this bug has been in the codebase for quite a long time.
-
CVE-2026-43187
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
xfs: delete attr leaf freemap entries when empty
Back in commit 2a2b5932db6758 ("xfs: fix attr leaf header freemap.size
underflow"), Brian Foster observed that it's possible for a small
freemap at the end of the end of the xattr entries array to experience
a size underflow when subtracting the space consumed by an expansion of
the entries array. There are only three freemap entries, which means
that it is not a complete index of all free space in the leaf block.
This code can leave behind a zero-length freemap entry with a nonzero
base. Subsequent setxattr operations can increase the base up to the
point that it overlaps with another freemap entry. This isn't in and of
itself a problem because the code in _leaf_add that finds free space
ignores any freemap entry with zero size.
However, there's another bug in the freemap update code in _leaf_add,
which is that it fails to update a freemap entry that begins midway
through the xattr entry that was just appended to the array. That can
result in the freemap containing two entries with the same base but
different sizes (0 for the "pushed-up" entry, nonzero for the entry
that's actually tracking free space). A subsequent _leaf_add can then
allocate xattr namevalue entries on top of the entries array, leading to
data loss. But fixing that is for later.
For now, eliminate the possibility of confusion by zeroing out the base
of any freemap entry that has zero size. Because the freemap is not
intended to be a complete index of free space, a subsequent failure to
find any free space for a new xattr will trigger block compaction, which
regenerates the freemap.
It looks like this bug has been in the codebase for quite a long time.
-
CVE-2026-43187
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
xfs: delete attr leaf freemap entries when empty
Back in commit 2a2b5932db6758 ("xfs: fix attr leaf header freemap.size
underflow"), Brian Foster observed that it's possible for a small
freemap at the end of the end of the xattr entries array to experience
a size underflow when subtracting the space consumed by an expansion of
the entries array. There are only three freemap entries, which means
that it is not a complete index of all free space in the leaf block.
This code can leave behind a zero-length freemap entry with a nonzero
base. Subsequent setxattr operations can increase the base up to the
point that it overlaps with another freemap entry. This isn't in and of
itself a problem because the code in _leaf_add that finds free space
ignores any freemap entry with zero size.
However, there's another bug in the freemap update code in _leaf_add,
which is that it fails to update a freemap entry that begins midway
through the xattr entry that was just appended to the array. That can
result in the freemap containing two entries with the same base but
different sizes (0 for the "pushed-up" entry, nonzero for the entry
that's actually tracking free space). A subsequent _leaf_add can then
allocate xattr namevalue entries on top of the entries array, leading to
data loss. But fixing that is for later.
For now, eliminate the possibility of confusion by zeroing out the base
of any freemap entry that has zero size. Because the freemap is not
intended to be a complete index of free space, a subsequent failure to
find any free space for a new xattr will trigger block compaction, which
regenerates the freemap.
It looks like this bug has been in the codebase for quite a long time.
-
CVE-2026-43187
•
published on May 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
xfs: delete attr leaf freemap entries when empty
Back in commit 2a2b5932db6758 ("xfs: fix attr leaf header freemap.size
underflow"), Brian Foster observed that it's possible for a small
freemap at the end of the end of the xattr entries array to experience
a size underflow when subtracting the space consumed by an expansion of
the entries array. There are only three freemap entries, which means
that it is not a complete index of all free space in the leaf block.
This code can leave behind a zero-length freemap entry with a nonzero
base. Subsequent setxattr operations can increase the base up to the
point that it overlaps with another freemap entry. This isn't in and of
itself a problem because the code in _leaf_add that finds free space
ignores any freemap entry with zero size.
However, there's another bug in the freemap update code in _leaf_add,
which is that it fails to update a freemap entry that begins midway
through the xattr entry that was just appended to the array. That can
result in the freemap containing two entries with the same base but
different sizes (0 for the "pushed-up" entry, nonzero for the entry
that's actually tracking free space). A subsequent _leaf_add can then
allocate xattr namevalue entries on top of the entries array, leading to
data loss. But fixing that is for later.
For now, eliminate the possibility of confusion by zeroing out the base
of any freemap entry that has zero size. Because the freemap is not
intended to be a complete index of free space, a subsequent failure to
find any free space for a new xattr will trigger block compaction, which
regenerates the freemap.
It looks like this bug has been in the codebase for quite a long time.