In the Linux kernel, the following vulnerability has been resolved:
jfs: Fix uninit-value access of imap allocated in the diMount() function
syzbot reports that hexdumpto_buffer is using uninit-value:
===================================================== BUG: KMSAN: uninit-value in hexdumptobuffer+0x888/0x1100 lib/hexdump.c:171 hexdumptobuffer+0x888/0x1100 lib/hexdump.c:171 printhexdump+0x13d/0x3e0 lib/hexdump.c:276 diFree+0x5ba/0x4350 fs/jfs/jfsimap.c:876 jfsevictinode+0x510/0x550 fs/jfs/inode.c:156 evict+0x723/0xd10 fs/inode.c:796 iputfinal fs/inode.c:1946 [inline] iput+0x97b/0xdb0 fs/inode.c:1972 txUpdateMap+0xf3e/0x1150 fs/jfs/jfstxnmgr.c:2367 txLazyCommit fs/jfs/jfstxnmgr.c:2664 [inline] jfslazycommit+0x627/0x11d0 fs/jfs/jfstxnmgr.c:2733 kthread+0x6b9/0xef0 kernel/kthread.c:464 retfromfork+0x6d/0x90 arch/x86/kernel/process.c:148 retfromforkasm+0x1a/0x30 arch/x86/entry/entry64.S:244
Uninit was created at: slabpostallochook mm/slub.c:4121 [inline] slaballocnode mm/slub.c:4164 [inline] _kmalloccachenoprof+0x8e3/0xdf0 mm/slub.c:4320 kmallocnoprof include/linux/slab.h:901 [inline] diMount+0x61/0x7f0 fs/jfs/jfsimap.c:105 jfsmount+0xa8e/0x11d0 fs/jfs/jfsmount.c:176 jfsfillsuper+0xa47/0x17c0 fs/jfs/super.c:523 gettreebdevflags+0x6ec/0x910 fs/super.c:1636 gettreebdev+0x37/0x50 fs/super.c:1659 jfsgettree+0x34/0x40 fs/jfs/super.c:635 vfsgettree+0xb1/0x5a0 fs/super.c:1814 donewmount+0x71f/0x15e0 fs/namespace.c:3560 pathmount+0x742/0x1f10 fs/namespace.c:3887 domount fs/namespace.c:3900 [inline] _dosysmount fs/namespace.c:4111 [inline] _sesysmount+0x71f/0x800 fs/namespace.c:4088 _x64sysmount+0xe4/0x150 fs/namespace.c:4088 x64syscall+0x39bf/0x3c30 arch/x86/include/generated/asm/syscalls64.h:166 dosyscallx64 arch/x86/entry/common.c:52 [inline] dosyscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
The reason is that imap is not properly initialized after memory allocation. It will cause the snprintf() function to write uninitialized data into linebuf within hexdumpto_buffer().
Fix this by using kzalloc instead of kmalloc to clear its content at the beginning in diMount().
[
{
"id": "CVE-2025-37742-47ef8008",
"deprecated": false,
"signature_version": "v1",
"signature_type": "Line",
"target": {
"file": "fs/jfs/jfs_imap.c"
},
"digest": {
"line_hashes": [
"166961760510607436376658349656635183560",
"232062660610268493603582875245669489637",
"13532534486099381166656255001401720359",
"26033194211715232061508921932871482517"
],
"threshold": 0.9
},
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@cab1852368dd74d629ee02abdbc559218ca64dde"
},
{
"id": "CVE-2025-37742-53b9bc00",
"deprecated": false,
"signature_version": "v1",
"signature_type": "Line",
"target": {
"file": "fs/jfs/jfs_imap.c"
},
"digest": {
"line_hashes": [
"166961760510607436376658349656635183560",
"232062660610268493603582875245669489637",
"13532534486099381166656255001401720359",
"26033194211715232061508921932871482517"
],
"threshold": 0.9
},
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@9629d7d66c621671d9a47afe27ca9336bfc8a9ea"
},
{
"id": "CVE-2025-37742-54ba13ab",
"deprecated": false,
"signature_version": "v1",
"signature_type": "Line",
"target": {
"file": "fs/jfs/jfs_imap.c"
},
"digest": {
"line_hashes": [
"166961760510607436376658349656635183560",
"232062660610268493603582875245669489637",
"13532534486099381166656255001401720359",
"26033194211715232061508921932871482517"
],
"threshold": 0.9
},
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@63148ce4904faa668daffdd1d3c1199ae315ef2c"
},
{
"id": "CVE-2025-37742-a064ffa3",
"deprecated": false,
"signature_version": "v1",
"signature_type": "Line",
"target": {
"file": "fs/jfs/jfs_imap.c"
},
"digest": {
"line_hashes": [
"166961760510607436376658349656635183560",
"232062660610268493603582875245669489637",
"13532534486099381166656255001401720359",
"26033194211715232061508921932871482517"
],
"threshold": 0.9
},
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@d0d7eca253ccd0619b3d2b683ffe32218ebca9ac"
},
{
"id": "CVE-2025-37742-aa211561",
"deprecated": false,
"signature_version": "v1",
"signature_type": "Line",
"target": {
"file": "fs/jfs/jfs_imap.c"
},
"digest": {
"line_hashes": [
"166961760510607436376658349656635183560",
"232062660610268493603582875245669489637",
"13532534486099381166656255001401720359",
"26033194211715232061508921932871482517"
],
"threshold": 0.9
},
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@4f10732712fce33e53703ffe5ed9155f23814097"
},
{
"id": "CVE-2025-37742-ba36a51c",
"deprecated": false,
"signature_version": "v1",
"signature_type": "Line",
"target": {
"file": "fs/jfs/jfs_imap.c"
},
"digest": {
"line_hashes": [
"166961760510607436376658349656635183560",
"232062660610268493603582875245669489637",
"13532534486099381166656255001401720359",
"26033194211715232061508921932871482517"
],
"threshold": 0.9
},
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@7057f3aab47629d38e54eae83505813cf0da1e4b"
},
{
"id": "CVE-2025-37742-c665a98e",
"deprecated": false,
"signature_version": "v1",
"signature_type": "Line",
"target": {
"file": "fs/jfs/jfs_imap.c"
},
"digest": {
"line_hashes": [
"166961760510607436376658349656635183560",
"232062660610268493603582875245669489637",
"13532534486099381166656255001401720359",
"26033194211715232061508921932871482517"
],
"threshold": 0.9
},
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@067347e00a3a7d04afed93f080c6c131e5dd15ee"
}
]