1 files changed, 28 insertions, 10 deletions

diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 23801b028530..afd823c9cbca 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -589,12 +589,17 @@ build_compression_ctxt(struct smb2_compression_capabilities_context *pneg_ctxt)
 	pneg_ctxt->DataLength =
 		cpu_to_le16(sizeof(struct smb2_compression_capabilities_context)
 			  - sizeof(struct smb2_neg_context));
-	pneg_ctxt->CompressionAlgorithmCount = cpu_to_le16(1);
+
+	/* This enables the usage of the Pattern_V1 algorithm */
+	pneg_ctxt->Flags = SMB2_COMPRESSION_CAPABILITIES_FLAG_CHAINED;
+	pneg_ctxt->CompressionAlgorithmCount = cpu_to_le16(2);
+
 	/*
-	 * Send the only algorithm we support (XXX: add others as they're
+	 * Send the algorithms we support (XXX: add others as they're
 	 * implemented).
 	 */
 	pneg_ctxt->CompressionAlgorithms[0] = SMB3_COMPRESS_LZ77;
+	pneg_ctxt->CompressionAlgorithms[1] = SMB3_COMPRESS_PATTERN;
 }
 
 static unsigned int
@@ -782,9 +787,13 @@ static void decode_compress_ctx(struct TCP_Server_Info *server,
 			 struct smb2_compression_capabilities_context *ctxt)
 {
 	unsigned int len = le16_to_cpu(ctxt->DataLength);
-	__le16 alg;
+	__le16 count, i;
+	int chained;
 
 	server->compression.enabled = false;
+	server->compression.chained = false;
+	count = ctxt->CompressionAlgorithmCount;
+	chained = !!(ctxt->Flags & SMB2_COMPRESSION_CAPABILITIES_FLAG_CHAINED);
 
 	/*
 	 * Caller checked that DataLength remains within SMB boundary. We still
@@ -796,18 +805,27 @@ static void decode_compress_ctx(struct TCP_Server_Info *server,
 		return;
 	}
 
-	if (le16_to_cpu(ctxt->CompressionAlgorithmCount) != 1) {
-		pr_warn_once("invalid SMB3 compress algorithm count\n");
+	if (unlikely(count != 2)) {
+		pr_warn_once("invalid SMB3 compress algorithm count '%u'\n", count);
 		return;
 	}
 
-	alg = ctxt->CompressionAlgorithms[0];
-	if (!smb_compress_alg_valid(alg, false)) {
-		pr_warn_once("invalid compression algorithm '%u'\n", alg);
-		return;
+	for (i = 0; i < count; i++) {
+		__le16 alg = ctxt->CompressionAlgorithms[i];
+
+		if (!smb_compress_alg_valid(alg, false)) {
+			pr_warn_once("invalid compression algorithm '%u'\n", alg);
+			return;
+		}
+
+		if (alg == SMB3_COMPRESS_PATTERN) {
+			if (chained)
+				server->compression.chained = true;
+		} else {
+			server->compression.alg = alg;
+		}
 	}
 
-	server->compression.alg = alg;
 	server->compression.enabled = true;
 }