Vulnerabilidades

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> smb/client: fix chown/chgrp with SMB3 POSIX Extensions<br /> <br /> Ownership (chown) and group (chgrp) modifications were being ignored when<br /> mounting with SMB3 POSIX Extensions unless CIFS_MOUNT_CIFS_ACL or<br /> CIFS_MOUNT_MODE_FROM_SID were also explicitly set.<br /> <br /> Fix this by checking for posix_extensions in cifs_setattr_nounix() when<br /> updating UID and GID, ensuring that id_mode_to_cifs_acl() is called to map<br /> and set the ownership/group information on the server.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ksmbd: validate NTLMv2 response before updating session key<br /> <br /> ksmbd_auth_ntlmv2() derives the NTLMv2 session key into<br /> sess-&gt;sess_key before it verifies the NTLMv2 response.<br /> ksmbd_decode_ntlmssp_auth_blob() then continues into KEY_XCH even<br /> when ksmbd_auth_ntlmv2() failed.<br /> <br /> With SMB3 multichannel binding, the failed authentication operates on<br /> an existing session and the session setup error path does not expire<br /> binding sessions. A client can send a binding session setup with a<br /> bad NT proof and KEY_XCH and still modify sess-&gt;sess_key before<br /> STATUS_LOGON_FAILURE is returned.<br /> <br /> Relevant path:<br /> <br /> smb2_sess_setup()<br /> -&gt; conn-&gt;binding = true<br /> -&gt; ntlm_authenticate()<br /> -&gt; session_user()<br /> -&gt; ksmbd_decode_ntlmssp_auth_blob()<br /> -&gt; ksmbd_auth_ntlmv2()<br /> -&gt; calc_ntlmv2_hash()<br /> -&gt; hmac_md5_usingrawkey(..., sess-&gt;sess_key)<br /> -&gt; crypto_memneq() returns mismatch<br /> -&gt; KEY_XCH arc4_crypt(..., sess-&gt;sess_key, ...)<br /> -&gt; out_err without expiring the binding session<br /> <br /> Derive the base session key into a local buffer and copy it to<br /> sess-&gt;sess_key only after the proof matches. Return immediately on<br /> authentication failure so KEY_XCH is only processed after successful<br /> authentication.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ksmbd: track the connection owning a byte-range lock<br /> <br /> SMB2_LOCK adds each granted byte-range lock to both the file lock list<br /> and the lock list of the connection which handled the request. The<br /> final close and durable handle paths, however, remove the connection<br /> list entry while holding fp-&gt;conn-&gt;llist_lock.<br /> <br /> With SMB3 multichannel, the connection handling the LOCK request can be<br /> different from the connection which opened the file. The entry can<br /> therefore be removed under a different spinlock from the one protecting<br /> the list it belongs to. A concurrent traversal can then access freed<br /> struct ksmbd_lock and struct file_lock objects.<br /> <br /> Record the connection owning each lock&amp;#39;s clist entry and hold a<br /> reference to it while the entry is linked. Use that connection and its<br /> llist_lock for unlock, rollback, close, and durable preserve. Durable<br /> reconnect assigns the new connection as the owner when publishing the<br /> locks again.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ksmbd: use opener credentials for ADS I/O<br /> <br /> Alternate data streams are stored as xattrs. Unlike regular file I/O,<br /> their read and write paths therefore call VFS xattr helpers which recheck<br /> inode permissions and LSM policy using the current task credentials.<br /> <br /> Run ADS I/O with the credentials captured when the SMB handle was opened.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ksmbd: use opener credentials for delete-on-close<br /> <br /> Delete-on-close can be completed by deferred or durable handle teardown,<br /> where no request work is available. Both the base-file unlink and the ADS<br /> xattr removal consequently run with the ksmbd worker credentials and can<br /> bypass filesystem permission checks.<br /> <br /> Run both operations with the credentials captured in struct file when the<br /> handle was opened. This preserves the authenticated user&amp;#39;s fsuid, fsgid,<br /> supplementary groups and capability restrictions at final close.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ksmbd: run set info with opener credentials<br /> <br /> SMB2 SET_INFO handlers call path-based VFS helpers after checking the<br /> access mask granted to the SMB handle. Those helpers perform their owner,<br /> inode permission and LSM checks using the current ksmbd worker credentials.<br /> <br /> Run the complete SET_INFO dispatch with the credentials captured when the<br /> handle was opened. This also removes the separate security information<br /> credential setup and keeps all SET_INFO classes under one credential scope.<br /> <br /> Direct override_creds() is used because it can nest with the request<br /> credential overrides already used by rename and link helpers.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ksmbd: add a WRITE_DAC/WRITE_OWNER check to SMB2 SET_INFO SECURITY<br /> <br /> commit cc57232cae23 ("ksmbd: fix FSCTL permission bypass by adding a<br /> permission check for FSCTL_SET_SPARSE") added a fp-&gt;daccess gate to<br /> fsctl_set_sparse and noted that "similar handle-level checks exist in other<br /> functions but are missing here." The SMB2 SET_INFO SECURITY arm is one of<br /> the missing ones, and the most security-relevant: smb2_set_info_sec() calls<br /> set_info_sec() with no per-handle access check.<br /> <br /> set_info_sec() (fs/smb/server/smbacl.c) re-permissions the file: it<br /> rewrites owner/group/mode via notify_change(), rewrites the POSIX ACL via<br /> set_posix_acl(), and on KSMBD_SHARE_FLAG_ACL_XATTR shares removes and<br /> rewrites the Windows security descriptor via ksmbd_vfs_set_sd_xattr().<br /> Every other persistent-mutation arm of the sibling handler<br /> smb2_set_info_file() checks fp-&gt;daccess first (FILE_WRITE_DATA /<br /> FILE_DELETE / FILE_WRITE_EA / FILE_WRITE_ATTRIBUTES); the SECURITY arm —<br /> which mutates the access control itself — is the only one with no gate.<br /> <br /> A client can therefore open a handle with FILE_WRITE_ATTRIBUTES only (no<br /> FILE_WRITE_DAC / FILE_WRITE_OWNER) and use SMB2_SET_INFO with InfoType<br /> SMB2_O_INFO_SECURITY to rewrite the file&amp;#39;s DACL and owner, granting itself<br /> access the handle&amp;#39;s daccess never carried. Unlike the FSCTL data arms this<br /> is a metadata/xattr operation, so there is no FMODE_WRITE VFS backstop —<br /> the missing fp-&gt;daccess check is the entire gate.<br /> <br /> Setting a security descriptor is the WRITE_DAC / WRITE_OWNER operation, so<br /> require at least one of those on the handle before re-permissioning the<br /> file. -EACCES is mapped to STATUS_ACCESS_DENIED by smb2_set_info().

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ksmbd: require source read access for duplicate extents<br /> <br /> FSCTL_DUPLICATE_EXTENTS_TO_FILE passes the source file directly to<br /> vfs_clone_file_range() or vfs_copy_file_range() without checking the SMB<br /> access mask granted to the source handle. A handle opened with attribute<br /> access can consequently be used to copy file contents into an<br /> attacker-readable destination.<br /> <br /> Require FILE_READ_DATA on the source handle before either VFS operation,<br /> matching other ksmbd data-copy paths.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> smb: client: Fix next buffer leak in receive_encrypted_standard()<br /> <br /> receive_encrypted_standard() allocates next_buffer before checking<br /> whether the number of compound PDUs already reached MAX_COMPOUND. If<br /> the limit check fails, the function returns immediately and the newly<br /> allocated next_buffer is not assigned to server-&gt;smallbuf/server-&gt;bigbuf,<br /> making it leaked.<br /> <br /> Move the MAX_COMPOUND check before allocating next_buffer.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> smb: client: mask server-provided mode to 07777 in modefromsid<br /> <br /> When modefromsid is active, parse_dacl() applies the server-provided<br /> sub_auth[2] value from the NFS mode SID to cf_mode without masking to<br /> 07777. Apply the correct masking, same as in the read path.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> smb: client: harden POSIX SID length parsing<br /> <br /> posix_info_sid_size() reads sid[1] to obtain the subauthority count,<br /> but its existing boundary check still accepts buffers with only one<br /> remaining byte. Require two bytes before reading sid[1] so all client<br /> paths that reuse the helper reject truncated POSIX SIDs safely.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> smb: client: fix double-free in SMB2_open() replay<br /> <br /> A response-bearing attempt can return a replayable error and free its<br /> response buffer. If SMB2_open_init() fails before the next send, cleanup<br /> retains the previous buffer type and frees that response again.<br /> <br /> Reset response bookkeeping before each attempt to prevent the stale free.