Description

In the Linux kernel, the following vulnerability has been resolved: jffs2: fix use-after-free in jffs2_clear_xattr_subsystem When we mount a jffs2 image, assume that the first few blocks of the image are normal and contain at least one xattr-related inode, but the next block is abnormal. As a result, an error is returned in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then called in jffs2_build_filesystem() and then again in jffs2_do_fill_super(). Finally we can observe the following report: ================================================================== BUG: KASAN: use-after-free in jffs2_clear_xattr_subsystem+0x95/0x6ac Read of size 8 at addr ffff8881243384e0 by task mount/719 Call Trace: dump_stack+0x115/0x16b jffs2_clear_xattr_subsystem+0x95/0x6ac jffs2_do_fill_super+0x84f/0xc30 jffs2_fill_super+0x2ea/0x4c0 mtd_get_sb+0x254/0x400 mtd_get_sb_by_nr+0x4f/0xd0 get_tree_mtd+0x498/0x840 jffs2_get_tree+0x25/0x30 vfs_get_tree+0x8d/0x2e0 path_mount+0x50f/0x1e50 do_mount+0x107/0x130 __se_sys_mount+0x1c5/0x2f0 __x64_sys_mount+0xc7/0x160 do_syscall_64+0x45/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Allocated by task 719: kasan_save_stack+0x23/0x60 __kasan_kmalloc.constprop.0+0x10b/0x120 kasan_slab_alloc+0x12/0x20 kmem_cache_alloc+0x1c0/0x870 jffs2_alloc_xattr_ref+0x2f/0xa0 jffs2_scan_medium.cold+0x3713/0x4794 jffs2_do_mount_fs.cold+0xa7/0x2253 jffs2_do_fill_super+0x383/0xc30 jffs2_fill_super+0x2ea/0x4c0 [...] Freed by task 719: kmem_cache_free+0xcc/0x7b0 jffs2_free_xattr_ref+0x78/0x98 jffs2_clear_xattr_subsystem+0xa1/0x6ac jffs2_do_mount_fs.cold+0x5e6/0x2253 jffs2_do_fill_super+0x383/0xc30 jffs2_fill_super+0x2ea/0x4c0 [...] The buggy address belongs to the object at ffff8881243384b8 which belongs to the cache jffs2_xattr_ref of size 48 The buggy address is located 40 bytes inside of 48-byte region [ffff8881243384b8, ffff8881243384e8) [...] ================================================================== The triggering of the BUG is shown in the following stack: ----------------------------------------------------------- jffs2_fill_super jffs2_do_fill_super jffs2_do_mount_fs jffs2_build_filesystem jffs2_scan_medium jffs2_scan_eraseblock <--- ERROR jffs2_clear_xattr_subsystem <--- free jffs2_clear_xattr_subsystem <--- free again ----------------------------------------------------------- An error is returned in jffs2_do_mount_fs(). If the error is returned by jffs2_sum_init(), the jffs2_clear_xattr_subsystem() does not need to be executed. If the error is returned by jffs2_build_filesystem(), the jffs2_clear_xattr_subsystem() also does not need to be executed again. So move jffs2_clear_xattr_subsystem() from 'out_inohash' to 'out_root' to fix this UAF problem.

Metrics

 

CVSS Version 4.0 CVSS Version 3.x CVSS Version 2.0

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

ADP:  CISA-ADP

Base Score:  7.8 HIGH

Vector:  CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS 2.0 Severity and Vector Strings:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

OR
          *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.20 up to (excluding) 5.4.189
          *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.33
          *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.17 up to (excluding) 5.17.2
          *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.15 up to (excluding) 4.19.238
          *cpe:2.3:o:linux:linux_kernel:*:*:*

kernel.org: https://git.kernel.org/stable/c/22327bd7988f21de3a53c1373f3b81542bfe1f44 Types: Patch

kernel.org: https://git.kernel.org/stable/c/30bf7244acf32f19cb722c39f7bc1c2a9f300422 Types: Patch

kernel.org: https://git.kernel.org/stable/c/3bd2454162ec6bbb5503233c804fce6e4b6dcec5 Types: Patch

kernel.org: https://git.kernel.org/stable/c/4c7c44ee1650677fbe89d86edbad9497b7679b5c Types: Patch

kernel.org: https://git.kernel.org/stable/c/7a75740206af5f17e9f3efa384211cba70213da1 Types: Patch

kernel.org: https://git.kernel.org/stable/c/7bb7428dd73991bf4b3a7a61b493ca50046c2b13 Types: Patch

kernel.org: https://git.kernel.org/stable/c/8c0f024f29e055840a5a89fe23b96ae3f921afed Types: Patch

kernel.org: https://git.kernel.org/stable/c/9150cb625b46f68d524f4cfd491f1aafc23e10a9 Types: Patch

kernel.org: https://git.kernel.org/stable/c/c3b07c875fa8f906f932976460fd14798596f101 Types: Patch

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE-416

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

jffs2: fix use-after-free in jffs2_clear_xattr_subsystem

When we mount a jffs2 image, assume that the first few blocks of
the image are normal and contain at least one xattr-related inode,
but the next block is abnormal. As a result, an error is returned
in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then
called in jffs2_build_filesystem() and then again in
jffs2_do_fill_super().

Finally we can observe the follo

https://git.kernel.org/stable/c/22327bd7988f21de3a53c1373f3b81542bfe1f44

https://git.kernel.org/stable/c/30bf7244acf32f19cb722c39f7bc1c2a9f300422

https://git.kernel.org/stable/c/3bd2454162ec6bbb5503233c804fce6e4b6dcec5

https://git.kernel.org/stable/c/4c7c44ee1650677fbe89d86edbad9497b7679b5c

https://git.kernel.org/stable/c/7a75740206af5f17e9f3efa384211cba70213da1

https://git.kernel.org/stable/c/7bb7428dd73991bf4b3a7a61b493ca50046c2b13

https://git.kernel.org/stable/c/8c0f024f29e055840a5a89fe23b96ae3f921afed

https://git.kernel.org/stable/c/9150cb625b46f68d524f4cfd491f1aafc23e10a9

https://git.kernel.org/stable/c/c3b07c875fa8f906f932976460fd14798596f101