[PATCH 10/18] smb:client: Improve tcon matching logic

[Samuel Cabrero <scabrero@suse.com>]

Split the network name and share name checking into their own functions,
and check if these names match only if its associated flag is enabled.
The registration address is always compared.

Signed-off-by: Samuel Cabrero <scabrero@suse.com>
---
 fs/smb/client/cifs_swn.c | 117 ++++++++++++++++++++++++---------------
 1 file changed, 72 insertions(+), 45 deletions(-)

diff --git a/fs/smb/client/cifs_swn.c b/fs/smb/client/cifs_swn.c
index 0d7e99203281..5728647a1e5d 100644
--- a/fs/smb/client/cifs_swn.c
+++ b/fs/smb/client/cifs_swn.c
@@ -72,13 +72,67 @@ static int cifs_swn_auth_info_ntlm(struct cifs_tcon *tcon, struct sk_buff *skb)
 	return 0;
 }
 
+static bool cifs_swn_reg_net_name_matches(const struct cifs_swn_reg *swnreg,
+					  const struct cifs_tcon *tcon)
+{
+	const char *unc = tcon->tree_name;
+	const char *host, *delim;
+	size_t host_len;
+
+	/* extract hostname, requires strlen(unc) >= 3 (\\a)*/
+	if (strnlen(unc, 3) < 3)
+		return false;
+
+	/* extract_hostname: skip all leading '\' characters */
+	for (host = unc; *host && *host == '\\'; host++)
+		;
+
+	if (!*host)
+		return false;
+
+	delim = strchr(host, '\\');
+	if (!delim)
+		return false;
+
+	host_len = delim - host;
+	if (strlen(swnreg->net_name) == host_len &&
+	    !strncasecmp(swnreg->net_name, host, host_len)) {
+		return true;
+	}
+	return false;
+}
+
+static bool cifs_swn_reg_share_name_matches(const struct cifs_swn_reg *swnreg,
+					    const struct cifs_tcon *tcon)
+{
+	const char *unc = tcon->tree_name;
+	const char *share, *delim;
+	size_t share_len;
+
+	/* extract share name, requires strlen(unc) >= 5 (\\a\b) */
+	if (strnlen(unc, 5) < 5)
+		return false;
+
+	/* extract share name, start at unc + 2, then first '\' onward */
+	share = unc + 2;
+	delim = strchr(share, '\\');
+	if (!delim)
+		return false;
+
+	share = delim + 1;
+	share_len = strlen(share);
+
+	if (strlen(swnreg->share_name) == share_len &&
+	    !strncasecmp(swnreg->share_name, share, share_len)) {
+		return true;
+	}
+	return false;
+}
+
 static bool cifs_swn_reg_tcon_matches(const struct cifs_swn_reg *swnreg,
 				      const struct cifs_tcon *tcon)
 {
-	const char *unc = tcon->tree_name;
 	struct sockaddr_storage *tcon_dstaddr;
-	const char *host, *share, *delim;
-	size_t host_len, share_len;
 
 	if (!tcon->use_witness)
 		return false;
@@ -88,54 +142,27 @@ static bool cifs_swn_reg_tcon_matches(const struct cifs_swn_reg *swnreg,
 	else
 		tcon_dstaddr = &tcon->ses->server->dstaddr;
 
+	/* Address must always match */
 	if (!cifs_match_ipaddr((struct sockaddr *)&swnreg->addr,
 			       (struct sockaddr *)tcon_dstaddr))
 		return false;
 
-	if (swnreg->net_name_notify) {
-		/* extract hostname, requires strlen(unc) >= 3 (\\a)*/
-		if (strnlen(unc, 3) < 3)
-			return false;
-
-		/* extract_hostname: skip all leading '\' characters */
-		for (host = unc; *host && *host == '\\'; host++)
-			;
-
-		if (!*host)
-			return false;
-
-		delim = strchr(host, '\\');
-		if (!delim)
-			return false;
-
-		host_len = delim - host;
-		if (strlen(swnreg->net_name) == host_len &&
-		    !strncasecmp(swnreg->net_name, host, host_len)) {
-			return true;
-		}
-	}
+	/* The network name notification is always enabled */
+	if (!cifs_swn_reg_net_name_matches(swnreg, tcon))
+		return false;
 
-	if (swnreg->share_name_notify) {
-		/* extract share name, requires strlen(unc) >= 5 (\\a\b) */
-		if (strnlen(unc, 5) < 5)
-			return false;
-
-		/* extract share name, start at unc + 2, then first '\' onward */
-		share = unc + 2;
-		delim = strchr(share, '\\');
-		if (!delim)
-			return false;
-
-		share = delim + 1;
-		share_len = strlen(share);
-
-		if (strlen(swnreg->share_name) == share_len &&
-		    !strncasecmp(swnreg->share_name, share, share_len)) {
-			return true;
-		}
-	}
+	/*
+	 * Share name notifications is enabled only if asymmetric
+	 * capability enabled otherwise ignored
+	 */
+	if (swnreg->share_name_notify !=
+	    (tcon->capabilities & SMB2_SHARE_CAP_ASYMMETRIC))
+		return false;
+	else if (swnreg->share_name_notify &&
+		 !cifs_swn_reg_share_name_matches(swnreg, tcon))
+		return false;
 
-	return false;
+	return true;
 }
 
 /*
-- 
2.54.0