6.1-stable review patch. If anyone has any objections, please let me know.
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From: Namjae Jeon linkinjeon@kernel.org
commit 9b493ab6f35178afd8d619800df9071992f715de upstream.
If client send two session setups with krb5 authenticate to ksmbd, null pointer dereference error in generate_encryptionkey could happen. sess->Preauth_HashValue is set to NULL if session is valid. So this patch skip generate encryption key if session is valid.
Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-27654 Signed-off-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 | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-)
--- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -1621,11 +1621,24 @@ static int krb5_authenticate(struct ksmb
rsp->SecurityBufferLength = cpu_to_le16(out_len);
- if ((conn->sign || server_conf.enforced_signing) || + /* + * If session state is SMB2_SESSION_VALID, We can assume + * that it is reauthentication. And the user/password + * has been verified, so return it here. + */ + if (sess->state == SMB2_SESSION_VALID) { + if (conn->binding) + goto binding_session; + return 0; + } + + if ((rsp->SessionFlags != SMB2_SESSION_FLAG_IS_GUEST_LE && + (conn->sign || server_conf.enforced_signing)) || (req->SecurityMode & SMB2_NEGOTIATE_SIGNING_REQUIRED)) sess->sign = true;
- if (smb3_encryption_negotiated(conn)) { + if (smb3_encryption_negotiated(conn) && + !(req->Flags & SMB2_SESSION_REQ_FLAG_BINDING)) { retval = conn->ops->generate_encryptionkey(conn, sess); if (retval) { ksmbd_debug(SMB, @@ -1638,6 +1651,7 @@ static int krb5_authenticate(struct ksmb sess->sign = false; }
+binding_session: if (conn->dialect >= SMB30_PROT_ID) { chann = lookup_chann_list(sess, conn); if (!chann) {