Bug 2395347 (CVE-2022-50293)

Summary: CVE-2022-50293 kernel: Linux kernel: Denial of Service in btrfs due to out-of-memory condition
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the Linux kernel's btrfs filesystem. A local user could trigger an out-of-memory condition when dropping file extent items, which would lead to a BUG_ON() call. This vulnerability could result in a kernel panic, causing a Denial of Service (DoS) to the system. The issue has been resolved by changing the BUG_ON() to properly abort the transaction and return an error.
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Description OSIDB Bzimport 2025-09-15 15:08:51 UTC 
In the Linux kernel, the following vulnerability has been resolved:

btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range

If we get -ENOMEM while dropping file extent items in a given range, at
btrfs_drop_extents(), due to failure to allocate memory when attempting to
increment the reference count for an extent or drop the reference count,
we handle it with a BUG_ON(). This is excessive, instead we can simply
abort the transaction and return the error to the caller. In fact most
callers of btrfs_drop_extents(), directly or indirectly, already abort
the transaction if btrfs_drop_extents() returns any error.

Also, we already have error paths at btrfs_drop_extents() that may return
-ENOMEM and in those cases we abort the transaction, like for example
anything that changes the b+tree may return -ENOMEM due to a failure to
allocate a new extent buffer when COWing an existing extent buffer, such
as a call to btrfs_duplicate_item() for example.

So replace the BUG_ON() calls with proper logic to abort the transaction
and return the error.
Comment 1 Jon Moroney 2025-09-15 20:44:46 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025091556-CVE-2022-50293-2dbe@gregkh/T