linux-cve-announce - CVE-2025-37779: lib/iov_iter: fix to increase non slab folio refcount

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2025050116-CVE-2025-37779-6bed@gregkh>
Date: Thu,  1 May 2025 15:07:27 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-37779: lib/iov_iter: fix to increase non slab folio refcount

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

lib/iov_iter: fix to increase non slab folio refcount

When testing EROFS file-backed mount over v9fs on qemu, I encountered a
folio UAF issue.  The page sanity check reports the following call trace. 
The root cause is that pages in bvec are coalesced across a folio bounary.
The refcount of all non-slab folios should be increased to ensure
p9_releas_pages can put them correctly.

BUG: Bad page state in process md5sum  pfn:18300
page: refcount:0 mapcount:0 mapping:00000000d5ad8e4e index:0x60 pfn:0x18300
head: order:0 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
aops:z_erofs_aops ino:30b0f dentry name(?):"GoogleExtServicesCn.apk"
flags: 0x100000000000041(locked|head|node=0|zone=1)
raw: 0100000000000041 dead000000000100 dead000000000122 ffff888014b13bd0
raw: 0000000000000060 0000000000000020 00000000ffffffff 0000000000000000
head: 0100000000000041 dead000000000100 dead000000000122 ffff888014b13bd0
head: 0000000000000060 0000000000000020 00000000ffffffff 0000000000000000
head: 0100000000000000 0000000000000000 ffffffffffffffff 0000000000000000
head: 0000000000000010 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
Call Trace:
 dump_stack_lvl+0x53/0x70
 bad_page+0xd4/0x220
 __free_pages_ok+0x76d/0xf30
 __folio_put+0x230/0x320
 p9_release_pages+0x179/0x1f0
 p9_virtio_zc_request+0xa2a/0x1230
 p9_client_zc_rpc.constprop.0+0x247/0x700
 p9_client_read_once+0x34d/0x810
 p9_client_read+0xf3/0x150
 v9fs_issue_read+0x111/0x360
 netfs_unbuffered_read_iter_locked+0x927/0x1390
 netfs_unbuffered_read_iter+0xa2/0xe0
 vfs_iocb_iter_read+0x2c7/0x460
 erofs_fileio_rq_submit+0x46b/0x5b0
 z_erofs_runqueue+0x1203/0x21e0
 z_erofs_readahead+0x579/0x8b0
 read_pages+0x19f/0xa70
 page_cache_ra_order+0x4ad/0xb80
 filemap_readahead.isra.0+0xe7/0x150
 filemap_get_pages+0x7aa/0x1890
 filemap_read+0x320/0xc80
 vfs_read+0x6c6/0xa30
 ksys_read+0xf9/0x1c0
 do_syscall_64+0x9e/0x1a0
 entry_SYSCALL_64_after_hwframe+0x71/0x79

The Linux kernel CVE team has assigned CVE-2025-37779 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.14 with commit b9c0e49abfca06f1a109acea834bcfc934f33f76 and fixed in 6.14.4 with commit d833f21162c4d536d729628f8cf1ee8d4110f2b7
	Issue introduced in 6.14 with commit b9c0e49abfca06f1a109acea834bcfc934f33f76 and fixed in 6.15-rc3 with commit 770c8d55c42868239c748a3ebc57c9e37755f842

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-37779
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	lib/iov_iter.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/d833f21162c4d536d729628f8cf1ee8d4110f2b7
	https://git.kernel.org/stable/c/770c8d55c42868239c748a3ebc57c9e37755f842