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 <ddiss@xxxxxxx>
---
v2: update changelog to also mention incorrect ctxt_size increment.
Note: this applies atop my previous assemble_neg_contexts cleanups
ksmbd: set NegotiateContextCount once instead of every inc
ksmbd: avoid duplicate negotiate ctx offset increments
fs/ksmbd/smb2pdu.c | 26 ++------------------------
1 file changed, 2 insertions(+), 24 deletions(-)
diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 9416c766483e..6dbc2300bd2a 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -747,19 +747,6 @@ 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)
{
@@ -823,17 +810,8 @@ 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);
--
2.35.3
