Bug 2376051 (CVE-2025-38139) - CVE-2025-38139 kernel: netfs: Fix oops in write-retry from mis-resetting the subreq iterator
Summary: CVE-2025-38139 kernel: netfs: Fix oops in write-retry from mis-resetting the ...
Keywords:
Status: NEW
Alias: CVE-2025-38139
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-07-03 09:02 UTC by OSIDB Bzimport
Modified: 2025-07-03 18:54 UTC (History)
0 users

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2025-07-03 09:02:20 UTC
In the Linux kernel, the following vulnerability has been resolved:

netfs: Fix oops in write-retry from mis-resetting the subreq iterator

Fix the resetting of the subrequest iterator in netfs_retry_write_stream()
to use the iterator-reset function as the iterator may have been shortened
by a previous retry.  In such a case, the amount of data to be written by
the subrequest is not "subreq->len" but "subreq->len -
subreq->transferred".

Without this, KASAN may see an error in iov_iter_revert():

   BUG: KASAN: slab-out-of-bounds in iov_iter_revert lib/iov_iter.c:633 [inline]
   BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x443/0x5a0 lib/iov_iter.c:611
   Read of size 4 at addr ffff88802912a0b8 by task kworker/u32:7/1147

   CPU: 1 UID: 0 PID: 1147 Comm: kworker/u32:7 Not tainted 6.15.0-rc6-syzkaller-00052-g9f35e33144ae #0 PREEMPT(full)
   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
   Workqueue: events_unbound netfs_write_collection_worker
   Call Trace:
    <TASK>
    __dump_stack lib/dump_stack.c:94 [inline]
    dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
    print_address_description mm/kasan/report.c:408 [inline]
    print_report+0xc3/0x670 mm/kasan/report.c:521
    kasan_report+0xe0/0x110 mm/kasan/report.c:634
    iov_iter_revert lib/iov_iter.c:633 [inline]
    iov_iter_revert+0x443/0x5a0 lib/iov_iter.c:611
    netfs_retry_write_stream fs/netfs/write_retry.c:44 [inline]
    netfs_retry_writes+0x166d/0x1a50 fs/netfs/write_retry.c:231
    netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
    netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
    process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
    process_scheduled_works kernel/workqueue.c:3319 [inline]
    worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
    kthread+0x3c2/0x780 kernel/kthread.c:464
    ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
    </TASK>

Comment 1 Avinash Hanwate 2025-07-03 18:52:48 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025070333-CVE-2025-38139-5152@gregkh/T


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