Vulnerability Details CVE-2022-50546
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix uninititialized value in 'ext4_evict_inode'
Syzbot found the following issue:
=====================================================
BUG: KMSAN: uninit-value in ext4_evict_inode+0xdd/0x26b0 fs/ext4/inode.c:180
ext4_evict_inode+0xdd/0x26b0 fs/ext4/inode.c:180
evict+0x365/0x9a0 fs/inode.c:664
iput_final fs/inode.c:1747 [inline]
iput+0x985/0xdd0 fs/inode.c:1773
__ext4_new_inode+0xe54/0x7ec0 fs/ext4/ialloc.c:1361
ext4_mknod+0x376/0x840 fs/ext4/namei.c:2844
vfs_mknod+0x79d/0x830 fs/namei.c:3914
do_mknodat+0x47d/0xaa0
__do_sys_mknodat fs/namei.c:3992 [inline]
__se_sys_mknodat fs/namei.c:3989 [inline]
__ia32_sys_mknodat+0xeb/0x150 fs/namei.c:3989
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
entry_SYSENTER_compat_after_hwframe+0x70/0x82
Uninit was created at:
__alloc_pages+0x9f1/0xe80 mm/page_alloc.c:5578
alloc_pages+0xaae/0xd80 mm/mempolicy.c:2285
alloc_slab_page mm/slub.c:1794 [inline]
allocate_slab+0x1b5/0x1010 mm/slub.c:1939
new_slab mm/slub.c:1992 [inline]
___slab_alloc+0x10c3/0x2d60 mm/slub.c:3180
__slab_alloc mm/slub.c:3279 [inline]
slab_alloc_node mm/slub.c:3364 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc_lru+0x6f3/0xb30 mm/slub.c:3429
alloc_inode_sb include/linux/fs.h:3117 [inline]
ext4_alloc_inode+0x5f/0x860 fs/ext4/super.c:1321
alloc_inode+0x83/0x440 fs/inode.c:259
new_inode_pseudo fs/inode.c:1018 [inline]
new_inode+0x3b/0x430 fs/inode.c:1046
__ext4_new_inode+0x2a7/0x7ec0 fs/ext4/ialloc.c:959
ext4_mkdir+0x4d5/0x1560 fs/ext4/namei.c:2992
vfs_mkdir+0x62a/0x870 fs/namei.c:4035
do_mkdirat+0x466/0x7b0 fs/namei.c:4060
__do_sys_mkdirat fs/namei.c:4075 [inline]
__se_sys_mkdirat fs/namei.c:4073 [inline]
__ia32_sys_mkdirat+0xc4/0x120 fs/namei.c:4073
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
entry_SYSENTER_compat_after_hwframe+0x70/0x82
CPU: 1 PID: 4625 Comm: syz-executor.2 Not tainted 6.1.0-rc4-syzkaller-62821-gcb231e2f67ec #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
=====================================================
Now, 'ext4_alloc_inode()' didn't init 'ei->i_flags'. If new inode failed
before set 'ei->i_flags' in '__ext4_new_inode()', then do 'iput()'. As after
6bc0d63dad7f commit will access 'ei->i_flags' in 'ext4_evict_inode()' which
will lead to access uninit-value.
To solve above issue just init 'ei->i_flags' in 'ext4_alloc_inode()'.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 5.9%
CVSS Severity
CVSS v3 Score 7.8
Products affected by CVE-2022-50546
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cpe:2.3:o:linux:linux_kernel:5.10.163
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cpe:2.3:o:linux:linux_kernel:5.15.61
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cpe:2.3:o:linux:linux_kernel:5.15.62
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cpe:2.3:o:linux:linux_kernel:5.15.63
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cpe:2.3:o:linux:linux_kernel:5.15.64
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cpe:2.3:o:linux:linux_kernel:5.15.65
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cpe:2.3:o:linux:linux_kernel:5.15.66
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cpe:2.3:o:linux:linux_kernel:5.15.67
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cpe:2.3:o:linux:linux_kernel:5.15.68
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cpe:2.3:o:linux:linux_kernel:5.15.69
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cpe:2.3:o:linux:linux_kernel:5.15.70
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cpe:2.3:o:linux:linux_kernel:5.15.71
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cpe:2.3:o:linux:linux_kernel:5.15.72
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cpe:2.3:o:linux:linux_kernel:5.15.73
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cpe:2.3:o:linux:linux_kernel:5.15.74
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cpe:2.3:o:linux:linux_kernel:5.15.75
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cpe:2.3:o:linux:linux_kernel:5.15.76
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cpe:2.3:o:linux:linux_kernel:5.15.77
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cpe:2.3:o:linux:linux_kernel:5.15.78
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cpe:2.3:o:linux:linux_kernel:5.15.79
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cpe:2.3:o:linux:linux_kernel:5.15.80
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cpe:2.3:o:linux:linux_kernel:5.15.81
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cpe:2.3:o:linux:linux_kernel:5.15.82
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cpe:2.3:o:linux:linux_kernel:5.15.83
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cpe:2.3:o:linux:linux_kernel:5.15.84
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cpe:2.3:o:linux:linux_kernel:5.15.85
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cpe:2.3:o:linux:linux_kernel:5.15.86
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cpe:2.3:o:linux:linux_kernel:5.18.18
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cpe:2.3:o:linux:linux_kernel:5.18.19
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cpe:2.3:o:linux:linux_kernel:5.19.10
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cpe:2.3:o:linux:linux_kernel:5.19.11
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cpe:2.3:o:linux:linux_kernel:5.19.12
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cpe:2.3:o:linux:linux_kernel:5.19.13
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cpe:2.3:o:linux:linux_kernel:5.19.14
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cpe:2.3:o:linux:linux_kernel:5.19.15
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cpe:2.3:o:linux:linux_kernel:5.19.16
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cpe:2.3:o:linux:linux_kernel:5.19.17
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cpe:2.3:o:linux:linux_kernel:5.19.2
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cpe:2.3:o:linux:linux_kernel:5.19.3
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cpe:2.3:o:linux:linux_kernel:5.19.4
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cpe:2.3:o:linux:linux_kernel:5.19.5
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cpe:2.3:o:linux:linux_kernel:5.19.6
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cpe:2.3:o:linux:linux_kernel:5.19.7
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cpe:2.3:o:linux:linux_kernel:5.19.8
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cpe:2.3:o:linux:linux_kernel:5.19.9
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cpe:2.3:o:linux:linux_kernel:6.0
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cpe:2.3:o:linux:linux_kernel:6.0.1
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cpe:2.3:o:linux:linux_kernel:6.0.10
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cpe:2.3:o:linux:linux_kernel:6.0.11
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cpe:2.3:o:linux:linux_kernel:6.0.12
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cpe:2.3:o:linux:linux_kernel:6.0.13
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cpe:2.3:o:linux:linux_kernel:6.0.14
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cpe:2.3:o:linux:linux_kernel:6.0.15
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cpe:2.3:o:linux:linux_kernel:6.0.16
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cpe:2.3:o:linux:linux_kernel:6.0.17
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cpe:2.3:o:linux:linux_kernel:6.0.2
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cpe:2.3:o:linux:linux_kernel:6.0.3
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cpe:2.3:o:linux:linux_kernel:6.0.4
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cpe:2.3:o:linux:linux_kernel:6.0.5
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cpe:2.3:o:linux:linux_kernel:6.0.6
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cpe:2.3:o:linux:linux_kernel:6.0.7
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cpe:2.3:o:linux:linux_kernel:6.0.8
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cpe:2.3:o:linux:linux_kernel:6.0.9
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cpe:2.3:o:linux:linux_kernel:6.1
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cpe:2.3:o:linux:linux_kernel:6.1.0
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cpe:2.3:o:linux:linux_kernel:6.1.1
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cpe:2.3:o:linux:linux_kernel:6.1.2
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cpe:2.3:o:linux:linux_kernel:6.1.3