PT-2026-61458 · Linux · Linux
CVE-2026-64141
·
Publicado
2026-07-19
·
Atualizado
2026-07-19
CVSS v3.1
7.5
Alta
| Vetor | AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix null pointer dereference in compare guid key()
session fd check() walks the per-inode m op list during durable-handle
session teardown and sets op->conn = NULL for every opinfo whose conn
matched the closing session's connection. The matching opinfo, however,
stays linked in its per-ClientGuid lease table list entry's lb->lease list
because destroy lease table() only runs on full TCP-connection teardown,
not on SESSION LOGOFF.
If the same TCP connection then negotiates a fresh session with the
same ClientGuid (ClientGuid is bound to NEGOTIATE, not the session, and
is unchanged across LOGOFF + SETUP) and issues a SMB2 CREATE with a
lease context on a different inode, find same lease key() walks
lb->lease list, reaches the stale opinfo, and calls compare guid key(),
which unconditionally dereferences opinfo->conn->ClientGUID. The conn
pointer is NULL and the kernel panics.
Reproducer requires only a successful SMB2 SESSION SETUP and a share
configured with 'durable handles = yes'. KASAN report on mainline
70390501d194:
general protection fault, probably for non-canonical address
0xdffffc0000000069: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000348-0x000000000000034f]
Workqueue: ksmbd-io handle ksmbd work
RIP: 0010:bcmp+0x5b/0x230
Call Trace:
compare guid key+0x4b/0xd0
find same lease key+0x324/0x690
smb2 open+0x6aea/0x8e60
handle ksmbd work+0x796/0xee0
...
Faulting address 0x348 is the offset of ClientGUID within struct
ksmbd conn, confirming opinfo->conn was NULL.
Read opinfo->conn once and bail out if it has been cleared by a
concurrent session fd check(). A half-detached opinfo cannot be the
owner of an active lease, so returning 0 is the correct match result.
Correção
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