In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ksmbd: fix null pointer dereference in compare_guid_key()<\/p>\n
session_fd_check() walks the per-inode m_op_list during durable-handle
\nsession teardown and sets op->conn = NULL for every opinfo whose conn
\nmatched the closing session’s connection. The matching opinfo, however,
\nstays linked in its per-ClientGuid lease_table_list entry’s lb->lease_list
\nbecause destroy_lease_table() only runs on full TCP-connection teardown,
\nnot on SESSION_LOGOFF.<\/p>\n
If the same TCP connection then negotiates a fresh session with the
\nsame ClientGuid (ClientGuid is bound to NEGOTIATE, not the session, and
\nis unchanged across LOGOFF + SETUP) and issues a SMB2 CREATE with a
\nlease context on a different inode, find_same_lease_key() walks
\nlb->lease_list, reaches the stale opinfo, and calls compare_guid_key(),
\nwhich unconditionally dereferences opinfo->conn->ClientGUID. The conn
\npointer is NULL and the kernel panics.<\/p>\n
Reproducer requires only a successful SMB2 SESSION_SETUP and a share
\nconfigured with ‘durable handles = yes’. KASAN report on mainline
\n70390501d194:<\/p>\n
general protection fault, probably for non-canonical address
\n 0xdffffc0000000069: 0000 [#1] SMP KASAN PTI
\n KASAN: null-ptr-deref in range [0x0000000000000348-0x000000000000034f]
\n Workqueue: ksmbd-io handle_ksmbd_work
\n RIP: 0010:bcmp+0x5b\/0x230
\n Call Trace:
\n compare_guid_key+0x4b\/0xd0
\n find_same_lease_key+0x324\/0x690
\n smb2_open+0x6aea\/0x8e60
\n handle_ksmbd_work+0x796\/0xee0
\n …<\/p>\n
Faulting address 0x348 is the offset of ClientGUID within struct
\nksmbd_conn, confirming opinfo->conn was NULL.<\/p>\n
Read opinfo->conn once and bail out if it has been cleared by a
\nconcurrent session_fd_check(). A half-detached opinfo cannot be the
\nowner of an active lease, so returning 0 is the correct match result.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ksmbd: fix null pointer dereference in compare_guid_key()<\/p>\n
session_fd_check() walks the per-inode m_op_list during durable-handle
\ns<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-15101","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/15101","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=15101"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=15101"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=15101"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}