Описание
In the Linux kernel, the following vulnerability has been resolved:
smb: client: bound dirent name against end of SMB response in cifs_filldir
cifs_filldir() copies the entry name out of an SMB1 TRANS2_FIND_FIRST /
FIND_NEXT response using a length (de.namelen) supplied by the server.
The kmalloc'd SMB response buffer is bounded, but nothing checks that
de.name + de.namelen still lies inside that buffer before the eventual
filldir64() -> verify_dirent_name() -> memchr() reads namelen bytes.
A hostile SMB1 server that returns an oversized FileNameLength in a
directory entry therefore causes memchr() to read past the end of the
response slab buffer. Reachable from any user who can list a directory
on a CIFS mount served by an attacker-controlled server (getdents64()
on the mounted directory):
BUG: KASAN: slab-out-of-bounds in memchr+0x71/0x80
Read of size 1 at addr ffff88800e0640cc by task poc/115
Call Trace:
dump_stack_lvl+0x64/0x80
print_report+0xce/0x620
kasan_report+0xec/0x120
memchr+0x71/0x80
filldir64+0x4c/0x6a0
cifs_filldir.constprop.0+0x9bb/0x1e00
cifs_readdir+0x2101/0x3380
iterate_dir+0x19c/0x520
__x64_sys_getdents64+0x126/0x210
do_syscall_64+0x107/0x5a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Pass the end-of-response pointer down to cifs_filldir() and reject
entries whose name would extend past that boundary.
This bug was discovered by Artiphishell's vTriage pipeline, which
generated a userspace reproducer (an emulated hostile SMB1 server plus
a getdents64() client) that reliably triggers the KASAN report on an
unpatched kernel. The fix below was drafted with the Claude coding
assistant; a userspace reproducer is available on request.
A flaw was found in the Linux kernel's SMB (Server Message Block) client subsystem. When a user lists files in a directory on a mounted share, a malicious SMB server can return a crafted directory entry with an oversized filename length. Because the client fails to verify that the filename remains within the response buffer, the kernel reads beyond the allocated memory boundaries, leading to a system crash and denial of service (DoS) or potential disclosure of sensitive memory contents.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 9 | kernel | Affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected |
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Дополнительная информация
Статус:
EPSS
8.1 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: smb: client: bound dirent name against end of SMB response in cifs_filldir cifs_filldir() copies the entry name out of an SMB1 TRANS2_FIND_FIRST / FIND_NEXT response using a length (de.namelen) supplied by the server. The kmalloc'd SMB response buffer is bounded, but nothing checks that de.name + de.namelen still lies inside that buffer before the eventual filldir64() -> verify_dirent_name() -> memchr() reads namelen bytes. A hostile SMB1 server that returns an oversized FileNameLength in a directory entry therefore causes memchr() to read past the end of the response slab buffer. Reachable from any user who can list a directory on a CIFS mount served by an attacker-controlled server (getdents64() on the mounted directory): BUG: KASAN: slab-out-of-bounds in memchr+0x71/0x80 Read of size 1 at addr ffff88800e0640cc by task poc/115 Call Trace: dump_stack_lvl+0x64/0x80 print_report+0xce/0x620 kasan_report+0xec/0x120 mem...
In the Linux kernel, the following vulnerability has been resolved: smb: client: bound dirent name against end of SMB response in cifs_filldir cifs_filldir() copies the entry name out of an SMB1 TRANS2_FIND_FIRST / FIND_NEXT response using a length (de.namelen) supplied by the server. The kmalloc'd SMB response buffer is bounded, but nothing checks that de.name + de.namelen still lies inside that buffer before the eventual filldir64() -> verify_dirent_name() -> memchr() reads namelen bytes. A hostile SMB1 server that returns an oversized FileNameLength in a directory entry therefore causes memchr() to read past the end of the response slab buffer. Reachable from any user who can list a directory on a CIFS mount served by an attacker-controlled server (getdents64() on the mounted directory): BUG: KASAN: slab-out-of-bounds in memchr+0x71/0x80 Read of size 1 at addr ffff88800e0640cc by task poc/115 Call Trace: dump_stack_lvl+0x64/0x80 print_report+0xce/0x620 kasan_repor
smb: client: bound dirent name against end of SMB response in cifs_filldir
In the Linux kernel, the following vulnerability has been resolved: s ...
In the Linux kernel, the following vulnerability has been resolved: smb: client: bound dirent name against end of SMB response in cifs_filldir cifs_filldir() copies the entry name out of an SMB1 TRANS2_FIND_FIRST / FIND_NEXT response using a length (de.namelen) supplied by the server. The kmalloc'd SMB response buffer is bounded, but nothing checks that de.name + de.namelen still lies inside that buffer before the eventual filldir64() -> verify_dirent_name() -> memchr() reads namelen bytes. A hostile SMB1 server that returns an oversized FileNameLength in a directory entry therefore causes memchr() to read past the end of the response slab buffer. Reachable from any user who can list a directory on a CIFS mount served by an attacker-controlled server (getdents64() on the mounted directory): BUG: KASAN: slab-out-of-bounds in memchr+0x71/0x80 Read of size 1 at addr ffff88800e0640cc by task poc/115 Call Trace: dump_stack_lvl+0x64/0x80 print_report+0xce/0x620 kasan_re...
EPSS
8.1 High
CVSS3