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

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On Thu, 22 Jul 2010 18:33:01 +0100
David Howells <dhowells@xxxxxxxxxx> wrote:

> 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@xxxxxxxxxx>
> ---
> 
>  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) {
> 

Looks good. I like the fact that we'll no longer be munging the source
string in cifs_convert_address.

Acked-by: Jeff Layton <jlayton@xxxxxxxxxx>
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