[PATCH 6.12 107/162] smb: client: fix off-by-8 bounds check in check_wsl_eas()

[PATCH 6.12 107/162] smb: client: fix off-by-8 bounds check in check_wsl_eas()

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 3d8b9d06bd3ac4c6846f5498800b0f5f8062e53b upstream.

The bounds check uses (u8 *)ea + nlen + 1 + vlen as the end of the EA
name and value, but ea_data sits at offset sizeof(struct
smb2_file_full_ea_info) = 8 from ea, not at offset 0.  The strncmp()
later reads ea->ea_data[0..nlen-1] and the value bytes follow at
ea_data[nlen+1..nlen+vlen], so the actual end is ea->ea_data + nlen + 1
+ vlen.  Isn't pointer math fun?

The earlier check (u8 *)ea > end - sizeof(*ea) only guarantees the
8-byte header is in bounds, but since the last EA is placed within 8
bytes of the end of the response, the name and value bytes are read past
the end of iov.

Fix this mess all up by using ea->ea_data as the base for the bounds
check.

An "untrusted" server can use this to leak up to 8 bytes of kernel heap
into the EA name comparison and influence which WSL xattr the data is
interpreted as.

Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Cc: stable <stable@kernel.org>
Assisted-by: gregkh_clanker_t1000
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/smb/client/smb2inode.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -125,7 +125,7 @@ static int check_wsl_eas(struct kvec *rs
 		nlen = ea->ea_name_length;
 		vlen = le16_to_cpu(ea->ea_value_length);
 		if (nlen != SMB2_WSL_XATTR_NAME_LEN ||
-		    (u8 *)ea + nlen + 1 + vlen > end)
+		    (u8 *)ea->ea_data + nlen + 1 + vlen > end)
 			return -EINVAL;
 
 		switch (vlen) {

[PATCH 6.12 108/162] ksmbd: validate EaNameLength in smb2_get_ea()

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 66751841212c2cc196577453c37f7774ff363f02 upstream.

smb2_get_ea() reads ea_req->EaNameLength from the client request and
passes it directly to strncmp() as the comparison length without
verifying that the length of the name really is the size of the input
buffer received.

Fix this up by properly checking the size of the name based on the value
received and the overall size of the request, to prevent a later
strncmp() call to use the length as a "trusted" size of the buffer.
Without this check, uninitialized heap values might be slowly leaked to
the client.

Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: <stable@kernel.org>
Assisted-by: gregkh_clanker_t1000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/smb/server/smb2pdu.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -4728,6 +4728,11 @@ static int smb2_get_ea(struct ksmbd_work
 
 		ea_req = (struct smb2_ea_info_req *)((char *)req +
 						     le16_to_cpu(req->InputBufferOffset));
+
+		if (le32_to_cpu(req->InputBufferLength) <
+		    offsetof(struct smb2_ea_info_req, name) +
+		    ea_req->EaNameLength)
+			return -EINVAL;
 	} else {
 		/* need to send all EAs, if no specific EA is requested*/
 		if (le32_to_cpu(req->Flags) & SL_RETURN_SINGLE_ENTRY)

[PATCH 6.12 109/162] ksmbd: require 3 sub-authorities before reading sub_auth[2]

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 53370cf9090777774e07fd9a8ebce67c6cc333ab upstream.

parse_dacl() compares each ACE SID against sid_unix_NFS_mode and on
match reads sid.sub_auth[2] as the file mode.  If sid_unix_NFS_mode is
the prefix S-1-5-88-3 with num_subauth = 2 then compare_sids() compares
only min(num_subauth, 2) sub-authorities so a client SID with
num_subauth = 2 and sub_auth = {88, 3} will match.

If num_subauth = 2 and the ACE is placed at the very end of the security
descriptor, sub_auth[2] will be  4 bytes past end_of_acl.  The
out-of-band bytes will then be masked to the low 9 bits and applied as
the file's POSIX mode, probably not something that is good to have
happen.

Fix this up by forcing the SID to actually carry a third sub-authority
before reading it at all.

Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: <stable@kernel.org>
Assisted-by: gregkh_clanker_t1000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/smb/server/smbacl.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/smb/server/smbacl.c
+++ b/fs/smb/server/smbacl.c
@@ -451,7 +451,8 @@ static void parse_dacl(struct mnt_idmap
 		ppace[i]->access_req =
 			smb_map_generic_desired_access(ppace[i]->access_req);
 
-		if (!(compare_sids(&ppace[i]->sid, &sid_unix_NFS_mode))) {
+		if (ppace[i]->sid.num_subauth >= 3 &&
+		    !(compare_sids(&ppace[i]->sid, &sid_unix_NFS_mode))) {
 			fattr->cf_mode =
 				le32_to_cpu(ppace[i]->sid.sub_auth[2]);
 			break;

[PATCH 6.12 110/162] ksmbd: fix mechToken leak when SPNEGO decode fails after token alloc

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ad0057fb91218914d6c98268718ceb9d59b388e1 upstream.

The kernel ASN.1 BER decoder calls action callbacks incrementally as it
walks the input.  When ksmbd_decode_negTokenInit() reaches the mechToken
[2] OCTET STRING element, ksmbd_neg_token_alloc() allocates
conn->mechToken immediately via kmemdup_nul().  If a later element in
the same blob is malformed, then the decoder will return nonzero after
the allocation is already live.  This could happen if mechListMIC [3]
overrunse the enclosing SEQUENCE.

decode_negotiation_token() then sets conn->use_spnego = false because
both the negTokenInit and negTokenTarg grammars failed.  The cleanup at
the bottom of smb2_sess_setup() is gated on use_spnego:

	if (conn->use_spnego && conn->mechToken) {
		kfree(conn->mechToken);
		conn->mechToken = NULL;
	}

so the kfree is skipped, causing the mechToken to never be freed.

This codepath is reachable pre-authentication, so untrusted clients can
cause slow memory leaks on a server without even being properly
authenticated.

Fix this up by not checking check for use_spnego, as it's not required,
so the memory will always be properly freed.  At the same time, always
free the memory in ksmbd_conn_free() incase some other failure path
forgot to free it.

Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: <stable@kernel.org>
Assisted-by: gregkh_clanker_t1000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/smb/server/connection.c |    1 +
 fs/smb/server/smb2pdu.c    |    2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

--- a/fs/smb/server/connection.c
+++ b/fs/smb/server/connection.c
@@ -39,6 +39,7 @@ void ksmbd_conn_free(struct ksmbd_conn *
 	xa_destroy(&conn->sessions);
 	kvfree(conn->request_buf);
 	kfree(conn->preauth_info);
+	kfree(conn->mechToken);
 	if (atomic_dec_and_test(&conn->refcnt)) {
 		conn->transport->ops->free_transport(conn->transport);
 		kfree(conn);
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -1921,7 +1921,7 @@ out_err:
 	else if (rc)
 		rsp->hdr.Status = STATUS_LOGON_FAILURE;
 
-	if (conn->use_spnego && conn->mechToken) {
+	if (conn->mechToken) {
 		kfree(conn->mechToken);
 		conn->mechToken = NULL;
 	}