[PATCH 1/3] ksmbd: fix wrong DataOffset validation of create context

[PATCH 1/3] ksmbd: fix wrong DataOffset validation of create context

[Namjae Jeon]

If ->DataOffset of create context is 0, DataBuffer size is not correctly
validated. This patch change wrong validation code and consider tag
length in request.

Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21824
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/smb/server/oplock.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c
index 6bc8a1e48171..9bc0103720f5 100644
--- a/fs/smb/server/oplock.c
+++ b/fs/smb/server/oplock.c
@@ -1481,7 +1481,7 @@ struct create_context *smb2_find_context_vals(void *open_req, const char *tag, i
 		    name_len < 4 ||
 		    name_off + name_len > cc_len ||
 		    (value_off & 0x7) != 0 ||
-		    (value_off && (value_off < name_off + name_len)) ||
+		    (value_len && value_off < name_off + (name_len < 8 ? 8 : name_len)) ||
 		    ((u64)value_off + value_len > cc_len))
 			return ERR_PTR(-EINVAL);
 
-- 
2.25.1

[PATCH 2/3] ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob()

[Namjae Jeon]

If authblob->SessionKey.Length is bigger than session key
size(CIFS_KEY_SIZE), slub overflow can happen in key exchange codes.
cifs_arc4_crypt copy to session key array from SessionKey from client.

Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21940
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/smb/server/auth.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/smb/server/auth.c b/fs/smb/server/auth.c
index af7b2cdba126..229a6527870d 100644
--- a/fs/smb/server/auth.c
+++ b/fs/smb/server/auth.c
@@ -355,6 +355,9 @@ int ksmbd_decode_ntlmssp_auth_blob(struct authenticate_message *authblob,
 		if (blob_len < (u64)sess_key_off + sess_key_len)
 			return -EINVAL;
 
+		if (sess_key_len > CIFS_KEY_SIZE)
+			return -EINVAL;
+
 		ctx_arc4 = kmalloc(sizeof(*ctx_arc4), GFP_KERNEL);
 		if (!ctx_arc4)
 			return -ENOMEM;
-- 
2.25.1

[PATCH 3/3] ksmbd: replace one-element array with flex-array member in struct smb2_ea_info

[Namjae Jeon]

UBSAN complains about out-of-bounds array indexes on 1-element arrays in
struct smb2_ea_info.

UBSAN: array-index-out-of-bounds in fs/smb/server/smb2pdu.c:4335:15
index 1 is out of range for type 'char [1]'
CPU: 1 PID: 354 Comm: kworker/1:4 Not tainted 6.5.0-rc4 #1
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop
Reference Platform, BIOS 6.00 07/22/2020
Workqueue: ksmbd-io handle_ksmbd_work [ksmbd]
Call Trace:
 <TASK>
 __dump_stack linux/lib/dump_stack.c:88
 dump_stack_lvl+0x48/0x70 linux/lib/dump_stack.c:106
 dump_stack+0x10/0x20 linux/lib/dump_stack.c:113
 ubsan_epilogue linux/lib/ubsan.c:217
 __ubsan_handle_out_of_bounds+0xc6/0x110 linux/lib/ubsan.c:348
 smb2_get_ea linux/fs/smb/server/smb2pdu.c:4335
 smb2_get_info_file linux/fs/smb/server/smb2pdu.c:4900
 smb2_query_info+0x63ae/0x6b20 linux/fs/smb/server/smb2pdu.c:5275
 __process_request linux/fs/smb/server/server.c:145
 __handle_ksmbd_work linux/fs/smb/server/server.c:213
 handle_ksmbd_work+0x348/0x10b0 linux/fs/smb/server/server.c:266
 process_one_work+0x85a/0x1500 linux/kernel/workqueue.c:2597
 worker_thread+0xf3/0x13a0 linux/kernel/workqueue.c:2748
 kthread+0x2b7/0x390 linux/kernel/kthread.c:389
 ret_from_fork+0x44/0x90 linux/arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x1b/0x30 linux/arch/x86/entry/entry_64.S:304
 </TASK>

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/smb/server/smb2pdu.c | 2 +-
 fs/smb/server/smb2pdu.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 2d4b8efaf19f..d12d995f52d7 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -4335,7 +4335,7 @@ static int smb2_get_ea(struct ksmbd_work *work, struct ksmbd_file *fp,
 		if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
 			name_len -= XATTR_USER_PREFIX_LEN;
 
-		ptr = (char *)(&eainfo->name + name_len + 1);
+		ptr = eainfo->name + name_len + 1;
 		buf_free_len -= (offsetof(struct smb2_ea_info, name) +
 				name_len + 1);
 		/* bailout if xattr can't fit in buf_free_len */
diff --git a/fs/smb/server/smb2pdu.h b/fs/smb/server/smb2pdu.h
index 2767c08a534a..d12cfd3b0927 100644
--- a/fs/smb/server/smb2pdu.h
+++ b/fs/smb/server/smb2pdu.h
@@ -361,7 +361,7 @@ struct smb2_ea_info {
 	__u8   Flags;
 	__u8   EaNameLength;
 	__le16 EaValueLength;
-	char name[1];
+	char name[];
 	/* optionally followed by value */
 } __packed; /* level 15 Query */
 
-- 
2.25.1