[PATCH 3/6] CIFS: Make cifs_convert_address() take a const src pointer and a length

[David Howells <dhowells@redhat.com>]

Make cifs_convert_address() take a const src pointer and a length so that all
the strlen() calls in their can be cut out and to make it unnecessary to modify
the src string.

Also return the data length from dns_resolve_server_name_to_ip() so that a
strlen() can be cut out of cifs_compose_mount_options() too.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/cifs/cifs_dfs_ref.c |    5 ++---
 fs/cifs/cifsproto.h    |    4 ++--
 fs/cifs/connect.c      |    1 +
 fs/cifs/dns_resolve.c  |   20 +++++++++-----------
 fs/cifs/netmisc.c      |   45 ++++++++++++++++++++++++---------------------
 5 files changed, 38 insertions(+), 37 deletions(-)

diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index ac19a6f..37543e8 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -141,7 +141,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
 	}
 
 	rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
-	if (rc != 0) {
+	if (rc < 0) {
 		cERROR(1, "%s: Failed to resolve server part of %s to IP: %d",
 			  __func__, *devname, rc);
 		goto compose_mount_options_err;
@@ -150,8 +150,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
 	 * assuming that we have 'unc=' and 'ip=' in
 	 * the original sb_mountdata
 	 */
-	md_len = strlen(sb_mountdata) + strlen(srvIP) +
-		strlen(ref->node_name) + 12;
+	md_len = strlen(sb_mountdata) + rc + strlen(ref->node_name) + 12;
 	mountdata = kzalloc(md_len+1, GFP_KERNEL);
 	if (mountdata == NULL) {
 		rc = -ENOMEM;
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 2eaebbd..1f54508 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -86,8 +86,8 @@ extern unsigned int smbCalcSize(struct smb_hdr *ptr);
 extern unsigned int smbCalcSize_LE(struct smb_hdr *ptr);
 extern int decode_negTokenInit(unsigned char *security_blob, int length,
 			struct TCP_Server_Info *server);
-extern int cifs_convert_address(struct sockaddr *dst, char *src);
-extern int cifs_fill_sockaddr(struct sockaddr *dst, char *src,
+extern int cifs_convert_address(struct sockaddr *dst, const char *src, int len);
+extern int cifs_fill_sockaddr(struct sockaddr *dst, const char *src, int len,
 				unsigned short int port);
 extern int map_smb_to_linux_error(struct smb_hdr *smb, int logErr);
 extern void header_assemble(struct smb_hdr *, char /* command */ ,
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 399b601..7a78b49 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1538,6 +1538,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
 	if (volume_info->UNCip && volume_info->UNC) {
 		rc = cifs_fill_sockaddr((struct sockaddr *)&addr,
 					volume_info->UNCip,
+					strlen(volume_info->UNCip),
 					volume_info->port);
 		if (!rc) {
 			/* we failed translating address */
diff --git a/fs/cifs/dns_resolve.c b/fs/cifs/dns_resolve.c
index ff6fa2f..8de3b98 100644
--- a/fs/cifs/dns_resolve.c
+++ b/fs/cifs/dns_resolve.c
@@ -40,11 +40,11 @@ static const struct cred *dns_resolver_cache;
  * 		0 - name is not IP
  */
 static int
-is_ip(char *name)
+is_ip(const char *name, int len)
 {
 	struct sockaddr_storage ss;
 
-	return cifs_convert_address((struct sockaddr *)&ss, name);
+	return cifs_convert_address((struct sockaddr *)&ss, name, len);
 }
 
 static int
@@ -54,6 +54,10 @@ dns_resolver_instantiate(struct key *key, const void *data,
 	int rc = 0;
 	char *ip;
 
+	/* make sure this looks like an address */
+	if (!is_ip(data, datalen))
+		return -EINVAL;
+
 	ip = kmalloc(datalen + 1, GFP_KERNEL);
 	if (!ip)
 		return -ENOMEM;
@@ -61,12 +65,6 @@ dns_resolver_instantiate(struct key *key, const void *data,
 	memcpy(ip, data, datalen);
 	ip[datalen] = '\0';
 
-	/* make sure this looks like an address */
-	if (!is_ip(ip)) {
-		kfree(ip);
-		return -EINVAL;
-	}
-
 	key->type_data.x[0] = datalen;
 	key->payload.data = ip;
 
@@ -93,7 +91,7 @@ struct key_type key_type_dns_resolver = {
  * 	unc - server UNC
  * output:
  * 	*ip_addr - pointer to server ip, caller responcible for freeing it.
- * return 0 on success
+ * return the length of the returned string on success
  */
 int
 dns_resolve_server_name_to_ip(const char *unc, char **ip_addr)
@@ -131,7 +129,7 @@ dns_resolve_server_name_to_ip(const char *unc, char **ip_addr)
 	memcpy(name, unc+2, len);
 	name[len] = 0;
 
-	if (is_ip(name)) {
+	if (is_ip(name, len)) {
 		cFYI(1, "%s: it is IP, skipping dns upcall: %s",
 					__func__, name);
 		data = name;
@@ -164,7 +162,7 @@ skip_upcall:
 							name,
 							*ip_addr
 					);
-			rc = 0;
+			rc = len;
 		} else {
 			rc = -ENOMEM;
 		}
diff --git a/fs/cifs/netmisc.c b/fs/cifs/netmisc.c
index 3489468..b7f5975 100644
--- a/fs/cifs/netmisc.c
+++ b/fs/cifs/netmisc.c
@@ -139,17 +139,18 @@ static const struct smb_to_posix_error mapping_table_ERRHRD[] = {
  * Returns 0 on failure.
  */
 static int
-cifs_inet_pton(const int address_family, const char *cp, void *dst)
+cifs_inet_pton(const int address_family, const char *cp, int len, void *dst)
 {
 	int ret = 0;
 
 	/* calculate length by finding first slash or NULL */
 	if (address_family == AF_INET)
-		ret = in4_pton(cp, -1 /* len */, dst, '\\', NULL);
+		ret = in4_pton(cp, len, dst, '\\', NULL);
 	else if (address_family == AF_INET6)
-		ret = in6_pton(cp, -1 /* len */, dst , '\\', NULL);
+		ret = in6_pton(cp, len, dst , '\\', NULL);
 
-	cFYI(DBG2, "address conversion returned %d for %s", ret, cp);
+	cFYI(DBG2, "address conversion returned %d for %*.*s",
+	     ret, len, len, cp);
 	if (ret > 0)
 		ret = 1;
 	return ret;
@@ -164,37 +165,39 @@ cifs_inet_pton(const int address_family, const char *cp, void *dst)
  * Returns 0 on failure.
  */
 int
-cifs_convert_address(struct sockaddr *dst, char *src)
+cifs_convert_address(struct sockaddr *dst, const char *src, int len)
 {
-	int rc;
-	char *pct, *endp;
+	int rc, alen, slen;
+	const char *pct;
+	char *endp, scope_id[13];
 	struct sockaddr_in *s4 = (struct sockaddr_in *) dst;
 	struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) dst;
 
 	/* IPv4 address */
-	if (cifs_inet_pton(AF_INET, src, &s4->sin_addr.s_addr)) {
+	if (cifs_inet_pton(AF_INET, src, len, &s4->sin_addr.s_addr)) {
 		s4->sin_family = AF_INET;
 		return 1;
 	}
 
-	/* temporarily terminate string */
-	pct = strchr(src, '%');
-	if (pct)
-		*pct = '\0';
-
-	rc = cifs_inet_pton(AF_INET6, src, &s6->sin6_addr.s6_addr);
-
-	/* repair temp termination (if any) and make pct point to scopeid */
-	if (pct)
-		*pct++ = '%';
+	/* attempt to exclude the scope ID from the address part */
+	pct = memchr(src, '%', len);
+	alen = pct ? pct - src : len;
 
+	rc = cifs_inet_pton(AF_INET6, src, alen, &s6->sin6_addr.s6_addr);
 	if (!rc)
 		return rc;
 
 	s6->sin6_family = AF_INET6;
 	if (pct) {
+		/* grab the scope ID */
+		slen = len - (alen + 1);
+		if (slen <= 0 || slen > 12)
+			return 0;
+		memcpy(scope_id, pct + 1, slen);
+		scope_id[slen] = '\0';
+
 		s6->sin6_scope_id = (u32) simple_strtoul(pct, &endp, 0);
-		if (!*pct || *endp)
+		if (endp != scope_id + slen)
 			return 0;
 	}
 
@@ -202,10 +205,10 @@ cifs_convert_address(struct sockaddr *dst, char *src)
 }
 
 int
-cifs_fill_sockaddr(struct sockaddr *dst, char *src,
+cifs_fill_sockaddr(struct sockaddr *dst, const char *src, int len,
 		   const unsigned short int port)
 {
-	if (!cifs_convert_address(dst, src))
+	if (!cifs_convert_address(dst, src, len))
 		return 0;
 
 	switch (dst->sa_family) {