Описание
In the Linux kernel, the following vulnerability has been resolved:
jffs2: prevent xattr node from overflowing the eraseblock
Add a check to make sure that the requested xattr node size is no larger
than the eraseblock minus the cleanmarker.
Unlike the usual inode nodes, the xattr nodes aren't split into parts
and spread across multiple eraseblocks, which means that a xattr node
must not occupy more than one eraseblock. If the requested xattr value is
too large, the xattr node can spill onto the next eraseblock, overwriting
the nodes and causing errors such as:
jffs2: argh. node added in wrong place at 0x0000b050(2)
jffs2: nextblock 0x0000a000, expected at 0000b00c
jffs2: error: (823) do_verify_xattr_datum: node CRC failed at 0x01e050,
read=0xfc892c93, calc=0x000000
jffs2: notice: (823) jffs2_get_inode_nodes: Node header CRC failed
at 0x01e00c. {848f,2fc4,0fef511f,59a3d171}
jffs2: Node at 0x0000000c with length 0x00001044 would run over the
end of the erase block
jffs2: Perhaps the file system was created with the wrong erase size?
jffs2: jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found
at 0x00000010: 0x1044 instead
This breaks the filesystem and can lead to KASAN crashes such as:
BUG: KASAN: slab-out-of-bounds in jffs2_sum_add_kvec+0x125e/0x15d0
Read of size 4 at addr ffff88802c31e914 by task repro/830
CPU: 0 PID: 830 Comm: repro Not tainted 6.9.0-rc3+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Arch Linux 1.16.3-1-1 04/01/2014
Call Trace:
dump_stack_lvl+0xc6/0x120
print_report+0xc4/0x620
? __virt_addr_valid+0x308/0x5b0
kasan_report+0xc1/0xf0
? jffs2_sum_add_kvec+0x125e/0x15d0
? jffs2_sum_add_kvec+0x125e/0x15d0
jffs2_sum_add_kvec+0x125e/0x15d0
jffs2_flash_direct_writev+0xa8/0xd0
jffs2_flash_writev+0x9c9/0xef0
? __x64_sys_setxattr+0xc4/0x160
? do_syscall_64+0x69/0x140
? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[...]
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
A vulnerability was found in the Linux kernel in the do_jffs2_setxattr() function where improper checks can lead to an out-of-bounds write error. This can occur when the requested xattr node size is larger than the size allocate by an eraseblock, which causes the xattr node to spill onto the next eraseblock, overwriting the nodes and potentially causing errors. This vulnerability can potentially lead to data corruption or system instability.
Отчет
A moderate impact out-of-bounds write flaw was found in the Linux kernel's JFFS2 file system. The do_jffs2_setxattr() function did not verify that the requested extended attribute (xattr) node size fits within a single erase block. Because JFFS2 xattr nodes are not split across erase blocks, a local privileged user could set an xattr value so large that the node spills onto the next erase block and overwrites existing nodes, corrupting the file system and potentially triggering out-of-bounds memory accesses that crash the kernel, resulting in data corruption, errors, or a denial of service (system instability). Red Hat Product Security has rated this flaw Moderate severity (CVSS 3.1 score of 5.5, CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) because exploitation requires local privileged access to a system with a JFFS2 file system and the impact is limited to availability; the higher NIST (7.1, Important) and CVE.org (7.8, Important) scores additionally credit confidentiality and integrity impacts that are not supported by Red Hat's assessment. According to the current Red Hat affectedness records, Red Hat Enterprise Linux (kernel and kernel-rt) across supported releases, as well as the Hosted OpenShift (ARO/OSD) and Fedora kernel components, are not affected by this flaw; the Red Hat Enterprise Linux 6 Extended Lifecycle Support kernel stream is out of support scope.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: jffs2: prevent xattr node from overflowing the eraseblock Add a check to make sure that the requested xattr node size is no larger than the eraseblock minus the cleanmarker. Unlike the usual inode nodes, the xattr nodes aren't split into parts and spread across multiple eraseblocks, which means that a xattr node must not occupy more than one eraseblock. If the requested xattr value is too large, the xattr node can spill onto the next eraseblock, overwriting the nodes and causing errors such as: jffs2: argh. node added in wrong place at 0x0000b050(2) jffs2: nextblock 0x0000a000, expected at 0000b00c jffs2: error: (823) do_verify_xattr_datum: node CRC failed at 0x01e050, read=0xfc892c93, calc=0x000000 jffs2: notice: (823) jffs2_get_inode_nodes: Node header CRC failed at 0x01e00c. {848f,2fc4,0fef511f,59a3d171} jffs2: Node at 0x0000000c with length 0x00001044 would run over the end of the erase block jffs2: Perhaps the ...
In the Linux kernel, the following vulnerability has been resolved: jffs2: prevent xattr node from overflowing the eraseblock Add a check to make sure that the requested xattr node size is no larger than the eraseblock minus the cleanmarker. Unlike the usual inode nodes, the xattr nodes aren't split into parts and spread across multiple eraseblocks, which means that a xattr node must not occupy more than one eraseblock. If the requested xattr value is too large, the xattr node can spill onto the next eraseblock, overwriting the nodes and causing errors such as: jffs2: argh. node added in wrong place at 0x0000b050(2) jffs2: nextblock 0x0000a000, expected at 0000b00c jffs2: error: (823) do_verify_xattr_datum: node CRC failed at 0x01e050, read=0xfc892c93, calc=0x000000 jffs2: notice: (823) jffs2_get_inode_nodes: Node header CRC failed at 0x01e00c. {848f,2fc4,0fef511f,59a3d171} jffs2: Node at 0x0000000c with length 0x00001044 would run over the end of the erase block jffs2: Perhaps the
In the Linux kernel, the following vulnerability has been resolved: j ...
In the Linux kernel, the following vulnerability has been resolved: jffs2: prevent xattr node from overflowing the eraseblock Add a check to make sure that the requested xattr node size is no larger than the eraseblock minus the cleanmarker. Unlike the usual inode nodes, the xattr nodes aren't split into parts and spread across multiple eraseblocks, which means that a xattr node must not occupy more than one eraseblock. If the requested xattr value is too large, the xattr node can spill onto the next eraseblock, overwriting the nodes and causing errors such as: jffs2: argh. node added in wrong place at 0x0000b050(2) jffs2: nextblock 0x0000a000, expected at 0000b00c jffs2: error: (823) do_verify_xattr_datum: node CRC failed at 0x01e050, read=0xfc892c93, calc=0x000000 jffs2: notice: (823) jffs2_get_inode_nodes: Node header CRC failed at 0x01e00c. {848f,2fc4,0fef511f,59a3d171} jffs2: Node at 0x0000000c with length 0x00001044 would run over the end of the erase block jffs2: Perhaps ...
Уязвимость компонента jffs2 ядра операционной системы Linux, позволяющая нарушителю вызвать отказ в обслуживании
EPSS
5.5 Medium
CVSS3