ksmbd: smbd: validate buffer descriptor structures

Check ChannelInfoOffset and ChannelInfoLength
to validate buffer descriptor structures.
And add a debug log to print the structures'
content.

Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 3926ca18dca4c4f21d19fbcd7aebf2ff112af8df..6806994383d9290e05d3eb9ac1d5a742ba239c14 100644 (file)
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -6126,13 +6126,26 @@ static int smb2_set_remote_key_for_rdma(struct ksmbd_work *work,
                                        __le16 ChannelInfoOffset,
                                        __le16 ChannelInfoLength)
 {
+       unsigned int i, ch_count;
+
        if (work->conn->dialect == SMB30_PROT_ID &&
            Channel != SMB2_CHANNEL_RDMA_V1)
                return -EINVAL;
 
-       if (ChannelInfoOffset == 0 ||
-           le16_to_cpu(ChannelInfoLength) < sizeof(*desc))
+       ch_count = le16_to_cpu(ChannelInfoLength) / sizeof(*desc);
+       if (ksmbd_debug_types & KSMBD_DEBUG_RDMA) {
+               for (i = 0; i < ch_count; i++) {
+                       pr_info("RDMA r/w request %#x: token %#x, length %#x\n",
+                               i,
+                               le32_to_cpu(desc[i].token),
+                               le32_to_cpu(desc[i].length));
+               }
+       }
+       if (ch_count != 1) {
+               ksmbd_debug(RDMA, "RDMA multiple buffer descriptors %d are not supported yet\n",
+                           ch_count);
                return -EINVAL;
+       }
 
        work->need_invalidate_rkey =
                (Channel == SMB2_CHANNEL_RDMA_V1_INVALIDATE);
@@ -6185,9 +6198,15 @@ int smb2_read(struct ksmbd_work *work)
 
        if (req->Channel == SMB2_CHANNEL_RDMA_V1_INVALIDATE ||
            req->Channel == SMB2_CHANNEL_RDMA_V1) {
+               unsigned int ch_offset = le16_to_cpu(req->ReadChannelInfoOffset);
+
+               if (ch_offset < offsetof(struct smb2_read_req, Buffer)) {
+                       err = -EINVAL;
+                       goto out;
+               }
                err = smb2_set_remote_key_for_rdma(work,
                                                   (struct smb2_buffer_desc_v1 *)
-                                                  &req->Buffer[0],
+                                                  ((char *)req + ch_offset),
                                                   req->Channel,
                                                   req->ReadChannelInfoOffset,
                                                   req->ReadChannelInfoLength);
@@ -6428,11 +6447,16 @@ int smb2_write(struct ksmbd_work *work)
 
        if (req->Channel == SMB2_CHANNEL_RDMA_V1 ||
            req->Channel == SMB2_CHANNEL_RDMA_V1_INVALIDATE) {
-               if (req->Length != 0 || req->DataOffset != 0)
-                       return -EINVAL;
+               unsigned int ch_offset = le16_to_cpu(req->WriteChannelInfoOffset);
+
+               if (req->Length != 0 || req->DataOffset != 0 ||
+                   ch_offset < offsetof(struct smb2_write_req, Buffer)) {
+                       err = -EINVAL;
+                       goto out;
+               }
                err = smb2_set_remote_key_for_rdma(work,
                                                   (struct smb2_buffer_desc_v1 *)
-                                                  &req->Buffer[0],
+                                                  ((char *)req + ch_offset),
                                                   req->Channel,
                                                   req->WriteChannelInfoOffset,
                                                   req->WriteChannelInfoLength);