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ksmbd: remove unused compression negotiate ctx packing

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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 d6c9ad23b4 ("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 d6c9ad23b4 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 <ddiss@suse.de>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
David Disseldorp 2023-04-04 16:29:54 +02:00 committed by Steve French
parent a12a07a85a
commit af36c51e0e
1 changed files with 2 additions and 24 deletions
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26
fs/ksmbd/smb2pdu.c
View File

@ -756,19 +756,6 @@ 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_capabilities_context *pneg_ctxt,
__le16 comp_algo)
{
pneg_ctxt->ContextType = SMB2_COMPRESSION_CAPABILITIES;
pneg_ctxt->DataLength =
cpu_to_le16(sizeof(struct smb2_compression_capabilities_context)
- sizeof(struct smb2_neg_context));
pneg_ctxt->Reserved = cpu_to_le32(0);
pneg_ctxt->CompressionAlgorithmCount = cpu_to_le16(1);
pneg_ctxt->Flags = 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)
{
@ -832,17 +819,8 @@ 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_capabilities_context *)
(pneg_ctxt + ctxt_size),
conn->compress_algorithm);
neg_ctxt_cnt++;
ctxt_size += sizeof(struct smb2_compression_capabilities_context) + 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);