Commit 66751841 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman Committed by Steve French
Browse files

ksmbd: validate EaNameLength in smb2_get_ea() 



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: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 1c137636

fs/smb/server/smb2pdu.c

+5 −0
Original line number Diff line number Diff line
@@ -4717,6 +4717,11 @@ static int smb2_get_ea(struct ksmbd_work *work, struct ksmbd_file *fp, 


		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)