From: David Disseldorp ddiss@suse.de
[ Upstream commit e7067a446264a7514fa1cfaa4052cdb6803bc6a2 ]
Confirm that the accessed pneg_ctxt->HashAlgorithms address sits within the SMB request boundary; deassemble_neg_contexts() only checks that the eight byte smb2_neg_context header + (client controlled) DataLength are within the packet boundary, which is insufficient.
Checking for sizeof(struct smb2_preauth_neg_context) is overkill given that the type currently assumes SMB311_SALT_SIZE bytes of trailing Salt.
Signed-off-by: David Disseldorp ddiss@suse.de Acked-by: Namjae Jeon linkinjeon@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Steve French stfrench@microsoft.com --- fs/ksmbd/smb2pdu.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-)
diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index 92fa2090ac54..472aa5fa0d10 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -907,17 +907,21 @@ static void assemble_neg_contexts(struct ksmbd_conn *conn, }
static __le32 decode_preauth_ctxt(struct ksmbd_conn *conn, - struct smb2_preauth_neg_context *pneg_ctxt) + struct smb2_preauth_neg_context *pneg_ctxt, + int len_of_ctxts) { - __le32 err = STATUS_NO_PREAUTH_INTEGRITY_HASH_OVERLAP; + /* + * sizeof(smb2_preauth_neg_context) assumes SMB311_SALT_SIZE Salt, + * which may not be present. Only check for used HashAlgorithms[1]. + */ + if (len_of_ctxts < 6) + return STATUS_INVALID_PARAMETER;
- if (pneg_ctxt->HashAlgorithms == SMB2_PREAUTH_INTEGRITY_SHA512) { - conn->preauth_info->Preauth_HashId = - SMB2_PREAUTH_INTEGRITY_SHA512; - err = STATUS_SUCCESS; - } + if (pneg_ctxt->HashAlgorithms != SMB2_PREAUTH_INTEGRITY_SHA512) + return STATUS_NO_PREAUTH_INTEGRITY_HASH_OVERLAP;
- return err; + conn->preauth_info->Preauth_HashId = SMB2_PREAUTH_INTEGRITY_SHA512; + return STATUS_SUCCESS; }
static void decode_encrypt_ctxt(struct ksmbd_conn *conn, @@ -1045,7 +1049,8 @@ static __le32 deassemble_neg_contexts(struct ksmbd_conn *conn, break;
status = decode_preauth_ctxt(conn, - (struct smb2_preauth_neg_context *)pctx); + (struct smb2_preauth_neg_context *)pctx, + len_of_ctxts); if (status != STATUS_SUCCESS) break; } else if (pctx->ContextType == SMB2_ENCRYPTION_CAPABILITIES) {