From 4f2e8aee0109dd16244c64fb2599127509bf1db5 Mon Sep 17 00:00:00 2001 From: David Disseldorp Date: Wed, 5 Apr 2023 22:21:07 +0900 Subject: [PATCH] ksmbd: remove unused compression negotiate ctx packing build_compression_ctxt() is currently unreachable due to conn.compress_algorithm remaining zero (SMB3_COMPRESS_NONE). It appears to have been broken in a couple of subtle ways over the years: - prior to d6c9ad23b421 ("ksmbd: use the common definitions for NEGOTIATE_PROTOCOL") smb2_compression_ctx.DataLength was set to 8, which didn't account for the single CompressionAlgorithms flexible array member. - post d6c9ad23b421 smb2_compression_capabilities_context CompressionAlgorithms is a three member array, while CompressionAlgorithmCount is set to indicate only one member. assemble_neg_contexts() ctxt_size is also incorrectly incremented by sizeof(struct smb2_compression_capabilities_context) + 2, which assumes one flexible array member. Signed-off-by: David Disseldorp Signed-off-by: Namjae Jeon --- smb2pdu.c | 26 ++------------------------ 1 file changed, 2 insertions(+), 24 deletions(-) diff --git a/smb2pdu.c b/smb2pdu.c index 7448bfd13..8560e4344 100644 --- a/smb2pdu.c +++ b/smb2pdu.c @@ -764,19 +764,6 @@ static void build_encrypt_ctxt(struct smb2_encryption_neg_context *pneg_ctxt, pneg_ctxt->Ciphers[0] = cipher_type; } -static void build_compression_ctxt(struct smb2_compression_ctx *pneg_ctxt, - __le16 comp_algo) -{ - pneg_ctxt->ContextType = SMB2_COMPRESSION_CAPABILITIES; - pneg_ctxt->DataLength = - cpu_to_le16(sizeof(struct smb2_compression_ctx) - - sizeof(struct smb2_neg_context)); - pneg_ctxt->Reserved = cpu_to_le32(0); - pneg_ctxt->CompressionAlgorithmCount = cpu_to_le16(1); - pneg_ctxt->Reserved1 = cpu_to_le32(0); - pneg_ctxt->CompressionAlgorithms[0] = comp_algo; -} - static void build_sign_cap_ctxt(struct smb2_signing_capabilities *pneg_ctxt, __le16 sign_algo) { @@ -840,17 +827,8 @@ static void assemble_neg_contexts(struct ksmbd_conn *conn, ctxt_size += sizeof(struct smb2_encryption_neg_context) + 2; } - if (conn->compress_algorithm) { - ctxt_size = round_up(ctxt_size, 8); - ksmbd_debug(SMB, - "assemble SMB2_COMPRESSION_CAPABILITIES context\n"); - /* Temporarily set to SMB3_COMPRESS_NONE */ - build_compression_ctxt((struct smb2_compression_ctx *) - (pneg_ctxt + ctxt_size), - conn->compress_algorithm); - neg_ctxt_cnt++; - ctxt_size += sizeof(struct smb2_compression_ctx) + 2; - } + /* compression context not yet supported */ + WARN_ON(conn->compress_algorithm != SMB3_COMPRESS_NONE); if (conn->posix_ext_supported) { ctxt_size = round_up(ctxt_size, 8);