From 95c99904f614f90797fc589c40c2050b8c1c42cb Mon Sep 17 00:00:00 2001 From: Suresh Jayaraman Date: Fri, 30 Jul 2010 18:01:17 +0530 Subject: [PATCH 01/10] cifs: update README Update the README file to reflect that now DebugData shows all the features enabled. Signed-off-by: Suresh Jayaraman Cc: Jeff Layton -- fs/cifs/README | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) Signed-off-by: Steve French --- fs/cifs/README | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/cifs/README b/fs/cifs/README index a727b7cb075f..a7081eeeb85d 100644 --- a/fs/cifs/README +++ b/fs/cifs/README @@ -568,8 +568,9 @@ module can be displayed via modinfo. Misc /proc/fs/cifs Flags and Debug Info ======================================= Informational pseudo-files: -DebugData Displays information about active CIFS sessions - and shares, as well as the cifs.ko version. +DebugData Displays information about active CIFS sessions and + shares, features enabled as well as the cifs.ko + version. Stats Lists summary resource usage information as well as per share statistics, if CONFIG_CIFS_STATS in enabled in the kernel configuration. From f579903ef3e392251dc7e93cb521ddb622fbf8e0 Mon Sep 17 00:00:00 2001 From: Suresh Jayaraman Date: Fri, 30 Jul 2010 18:25:56 +0530 Subject: [PATCH 02/10] cifs: show features compiled in as part of DebugData Fixed the nit pointed out by Jeff. From: Suresh Jayaraman Subject: [PATCH 1/2] cifs: show features compiled in as part of DebugData This patch adds the features that are compiled in to the CIFS debugging data as shown below: $cat /proc/fs/cifs/DebugData Display Internal CIFS Data Structures for Debugging --------------------------------------------------- CIFS Version 1.64 Features: dfs fscache posix spnego xattr Active VFS Requests: 0 ... This patch provides a definitive way to tell what features are currently enabled in the running kernel. This could also help debugging. Signed-off-by: Suresh Jayaraman Cc: Jeff Layton Signed-off-by: Steve French --- fs/cifs/cifs_debug.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c index 4fce6e61b34e..eb1ba493489f 100644 --- a/fs/cifs/cifs_debug.c +++ b/fs/cifs/cifs_debug.c @@ -119,6 +119,31 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v) "Display Internal CIFS Data Structures for Debugging\n" "---------------------------------------------------\n"); seq_printf(m, "CIFS Version %s\n", CIFS_VERSION); + seq_printf(m, "Features: "); +#ifdef CONFIG_CIFS_DFS_UPCALL + seq_printf(m, "dfs"); + seq_putc(m, ' '); +#endif +#ifdef CONFIG_CIFS_FSCACHE + seq_printf(m, "fscache"); + seq_putc(m, ' '); +#endif +#ifdef CONFIG_CIFS_WEAK_PW_HASH + seq_printf(m, "lanman"); + seq_putc(m, ' '); +#endif +#ifdef CONFIG_CIFS_POSIX + seq_printf(m, "posix"); + seq_putc(m, ' '); +#endif +#ifdef CONFIG_CIFS_UPCALL + seq_printf(m, "spnego"); + seq_putc(m, ' '); +#endif +#ifdef CONFIG_CIFS_XATTR + seq_printf(m, "xattr"); +#endif + seq_putc(m, '\n'); seq_printf(m, "Active VFS Requests: %d\n", GlobalTotalActiveXid); seq_printf(m, "Servers:"); From 67b7626a0512d12e34b38ff45e32c693cf9c79a1 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 22 Jul 2010 18:33:01 +0100 Subject: [PATCH 03/10] CIFS: Make cifs_convert_address() take a const src pointer and a length 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. Acked-by: Jeff Layton Signed-off-by: David Howells Signed-off-by: Steve French --- 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 dc1ed50ea06e..d6ced7aa23cf 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 2eaebbd31132..1f5450814087 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 2a43a0aca965..95c2ea67edfb 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -1543,6 +1543,7 @@ 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 3ad7f4300c45..aa967e7917f8 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 c6721ee26dbc..f97851119e6c 100644 --- a/fs/cifs/netmisc.c +++ b/fs/cifs/netmisc.c @@ -140,17 +140,18 @@ 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; @@ -165,37 +166,39 @@ 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; } @@ -203,10 +206,10 @@ 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) { From 5acfec2502cf60a91dc1959e476b588ecb3a1b8a Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Mon, 2 Aug 2010 17:43:54 -0400 Subject: [PATCH 04/10] cifs: reduce false positives with inode aliasing serverino autodisable It turns out that not all directory inodes with dentries on the i_dentry list are unusable here. We only consider them unusable if they are still hashed or if they have a root dentry attached. Full disclosure -- this check is inherently racy. There's nothing that stops someone from slapping a new dentry onto this inode just after this check, or hashing an existing one that's already attached. So, this is really a "best effort" thing to work around misbehaving servers. Signed-off-by: Jeff Layton Signed-off-by: Steve French --- fs/cifs/inode.c | 43 +++++++++++++++++++++++++++++++------------ 1 file changed, 31 insertions(+), 12 deletions(-) diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c index a15b3a9bbff4..dc4c47ab9588 100644 --- a/fs/cifs/inode.c +++ b/fs/cifs/inode.c @@ -732,15 +732,9 @@ cifs_find_inode(struct inode *inode, void *opaque) if ((inode->i_mode & S_IFMT) != (fattr->cf_mode & S_IFMT)) return 0; - /* - * uh oh -- it's a directory. We can't use it since hardlinked dirs are - * verboten. Disable serverino and return it as if it were found, the - * caller can discard it, generate a uniqueid and retry the find - */ - if (S_ISDIR(inode->i_mode) && !list_empty(&inode->i_dentry)) { + /* if it's not a directory or has no dentries, then flag it */ + if (S_ISDIR(inode->i_mode) && !list_empty(&inode->i_dentry)) fattr->cf_flags |= CIFS_FATTR_INO_COLLISION; - cifs_autodisable_serverino(CIFS_SB(inode->i_sb)); - } return 1; } @@ -754,6 +748,27 @@ cifs_init_inode(struct inode *inode, void *opaque) return 0; } +/* + * walk dentry list for an inode and report whether it has aliases that + * are hashed. We use this to determine if a directory inode can actually + * be used. + */ +static bool +inode_has_hashed_dentries(struct inode *inode) +{ + struct dentry *dentry; + + spin_lock(&dcache_lock); + list_for_each_entry(dentry, &inode->i_dentry, d_alias) { + if (!d_unhashed(dentry) || IS_ROOT(dentry)) { + spin_unlock(&dcache_lock); + return true; + } + } + spin_unlock(&dcache_lock); + return false; +} + /* Given fattrs, get a corresponding inode */ struct inode * cifs_iget(struct super_block *sb, struct cifs_fattr *fattr) @@ -769,12 +784,16 @@ retry_iget5_locked: inode = iget5_locked(sb, hash, cifs_find_inode, cifs_init_inode, fattr); if (inode) { - /* was there a problematic inode number collision? */ + /* was there a potentially problematic inode collision? */ if (fattr->cf_flags & CIFS_FATTR_INO_COLLISION) { - iput(inode); - fattr->cf_uniqueid = iunique(sb, ROOT_I); fattr->cf_flags &= ~CIFS_FATTR_INO_COLLISION; - goto retry_iget5_locked; + + if (inode_has_hashed_dentries(inode)) { + cifs_autodisable_serverino(CIFS_SB(sb)); + iput(inode); + fattr->cf_uniqueid = iunique(sb, ROOT_I); + goto retry_iget5_locked; + } } cifs_fattr_to_inode(inode, fattr); From ba5dadbf4e7b531bd7ccecffb4d3935c80a3372e Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 3 Aug 2010 10:19:50 -0400 Subject: [PATCH 05/10] cifs: account for new creduid=0x%x parameter in spnego upcall string The commit that added the creduid=0x%x parameter failed to increase the buffer allocation to account for it. Reported-by: J. Bruce Fields Signed-off-by: Jeff Layton Signed-off-by: Steve French --- fs/cifs/cifs_spnego.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/cifs/cifs_spnego.c b/fs/cifs/cifs_spnego.c index 6effccff85a5..87044906cd1f 100644 --- a/fs/cifs/cifs_spnego.c +++ b/fs/cifs/cifs_spnego.c @@ -84,6 +84,9 @@ struct key_type cifs_spnego_key_type = { /* strlen of ";uid=0x" */ #define UID_KEY_LEN 7 +/* strlen of ";creduid=0x" */ +#define CREDUID_KEY_LEN 11 + /* strlen of ";user=" */ #define USER_KEY_LEN 6 @@ -107,6 +110,7 @@ cifs_get_spnego_key(struct cifsSesInfo *sesInfo) IP_KEY_LEN + INET6_ADDRSTRLEN + MAX_MECH_STR_LEN + UID_KEY_LEN + (sizeof(uid_t) * 2) + + CREDUID_KEY_LEN + (sizeof(uid_t) * 2) + USER_KEY_LEN + strlen(sesInfo->userName) + PID_KEY_LEN + (sizeof(pid_t) * 2) + 1; From 1a4240f4764ac78adbf4b0ebb49b3bd8c72ffa11 Mon Sep 17 00:00:00 2001 From: Wang Lei Date: Wed, 4 Aug 2010 15:16:33 +0100 Subject: [PATCH 06/10] DNS: Separate out CIFS DNS Resolver code Separate out the DNS resolver key type from the CIFS filesystem into its own module so that it can be made available for general use, including the AFS filesystem module. This facility makes it possible for the kernel to upcall to userspace to have it issue DNS requests, package up the replies and present them to the kernel in a useful form. The kernel is then able to cache the DNS replies as keys can be retained in keyrings. Resolver keys are of type "dns_resolver" and have a case-insensitive description that is of the form "[:]". The optional indicates the particular DNS lookup and packaging that's required. The is the query to be made. If isn't given, a basic hostname to IP address lookup is made, and the result is stored in the key in the form of a printable string consisting of a comma-separated list of IPv4 and IPv6 addresses. This key type is supported by userspace helpers driven from /sbin/request-key and configured through /etc/request-key.conf. The cifs.upcall utility is invoked for UNC path server name to IP address resolution. The CIFS functionality is encapsulated by the dns_resolve_unc_to_ip() function, which is used to resolve a UNC path to an IP address for CIFS filesystem. This part remains in the CIFS module for now. See the added Documentation/networking/dns_resolver.txt for more information. Signed-off-by: Wang Lei Signed-off-by: David Howells Acked-by: Jeff Layton Signed-off-by: Steve French --- Documentation/networking/dns_resolver.txt | 146 ++++++++++++++ fs/cifs/Kconfig | 17 +- fs/cifs/cifsfs.c | 13 +- fs/cifs/dns_resolve.c | 225 +++++----------------- fs/cifs/dns_resolve.h | 2 - include/keys/dns_resolver-type.h | 23 +++ include/linux/dns_resolver.h | 34 ++++ net/Kconfig | 1 + net/Makefile | 1 + net/dns_resolver/Kconfig | 27 +++ net/dns_resolver/Makefile | 7 + net/dns_resolver/dns_key.c | 210 ++++++++++++++++++++ net/dns_resolver/dns_query.c | 159 +++++++++++++++ net/dns_resolver/internal.h | 44 +++++ 14 files changed, 706 insertions(+), 203 deletions(-) create mode 100644 Documentation/networking/dns_resolver.txt create mode 100644 include/keys/dns_resolver-type.h create mode 100644 include/linux/dns_resolver.h create mode 100644 net/dns_resolver/Kconfig create mode 100644 net/dns_resolver/Makefile create mode 100644 net/dns_resolver/dns_key.c create mode 100644 net/dns_resolver/dns_query.c create mode 100644 net/dns_resolver/internal.h diff --git a/Documentation/networking/dns_resolver.txt b/Documentation/networking/dns_resolver.txt new file mode 100644 index 000000000000..d8e0ce1d38c7 --- /dev/null +++ b/Documentation/networking/dns_resolver.txt @@ -0,0 +1,146 @@ + =================== + DNS Resolver Module + =================== + +Contents: + + - Overview. + - Compilation. + - Setting up. + - Usage. + - Mechanism. + - Debugging. + + +======== +OVERVIEW +======== + +The DNS resolver module provides a way for kernel services to make DNS queries +by way of requesting a key of key type dns_resolver. These queries are +upcalled to userspace through /sbin/request-key. + +These routines must be supported by userspace tools dns.upcall, cifs.upcall and +request-key. It is under development and does not yet provide the full feature +set. The features it does support include: + + (*) Implements the dns_resolver key_type to contact userspace. + +It does not yet support the following AFS features: + + (*) Dns query support for AFSDB resource record. + +This code is extracted from the CIFS filesystem. + + +=========== +COMPILATION +=========== + +The module should be enabled by turning on the kernel configuration options: + + CONFIG_DNS_RESOLVER - tristate "DNS Resolver support" + + +========== +SETTING UP +========== + +To set up this facility, the /etc/request-key.conf file must be altered so that +/sbin/request-key can appropriately direct the upcalls. For example, to handle +basic dname to IPv4/IPv6 address resolution, the following line should be +added: + + #OP TYPE DESC CO-INFO PROGRAM ARG1 ARG2 ARG3 ... + #====== ============ ======= ======= ========================== + create dns_resolver * * /usr/sbin/cifs.upcall %k + +To direct a query for query type 'foo', a line of the following should be added +before the more general line given above as the first match is the one taken. + + create dns_resolver foo:* * /usr/sbin/dns.foo %k + + + +===== +USAGE +===== + +To make use of this facility, one of the following functions that are +implemented in the module can be called after doing: + + #include + + (1) int dns_query(const char *type, const char *name, size_t namelen, + const char *options, char **_result, time_t *_expiry); + + This is the basic access function. It looks for a cached DNS query and if + it doesn't find it, it upcalls to userspace to make a new DNS query, which + may then be cached. The key description is constructed as a string of the + form: + + [:] + + where optionally specifies the particular upcall program to invoke, + and thus the type of query to do, and specifies the string to be + looked up. The default query type is a straight hostname to IP address + set lookup. + + The name parameter is not required to be a NUL-terminated string, and its + length should be given by the namelen argument. + + The options parameter may be NULL or it may be a set of options + appropriate to the query type. + + The return value is a string appropriate to the query type. For instance, + for the default query type it is just a list of comma-separated IPv4 and + IPv6 addresses. The caller must free the result. + + The length of the result string is returned on success, and a -ve error + code is returned otherwise. -EKEYREJECTED will be returned if the DNS + lookup failed. + + If _expiry is non-NULL, the expiry time (TTL) of the result will be + returned also. + + +========= +MECHANISM +========= + +The dnsresolver module registers a key type called "dns_resolver". Keys of +this type are used to transport and cache DNS lookup results from userspace. + +When dns_query() is invoked, it calls request_key() to search the local +keyrings for a cached DNS result. If that fails to find one, it upcalls to +userspace to get a new result. + +Upcalls to userspace are made through the request_key() upcall vector, and are +directed by means of configuration lines in /etc/request-key.conf that tell +/sbin/request-key what program to run to instantiate the key. + +The upcall handler program is responsible for querying the DNS, processing the +result into a form suitable for passing to the keyctl_instantiate_key() +routine. This then passes the data to dns_resolver_instantiate() which strips +off and processes any options included in the data, and then attaches the +remainder of the string to the key as its payload. + +The upcall handler program should set the expiry time on the key to that of the +lowest TTL of all the records it has extracted a result from. This means that +the key will be discarded and recreated when the data it holds has expired. + +dns_query() returns a copy of the value attached to the key, or an error if +that is indicated instead. + +See for further information about +request-key function. + + +========= +DEBUGGING +========= + +Debugging messages can be turned on dynamically by writing a 1 into the +following file: + + /sys/module/dnsresolver/parameters/debug diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig index 5739fd7f88b4..57f0aa9f141f 100644 --- a/fs/cifs/Kconfig +++ b/fs/cifs/Kconfig @@ -71,14 +71,14 @@ config CIFS_WEAK_PW_HASH If unsure, say N. config CIFS_UPCALL - bool "Kerberos/SPNEGO advanced session setup" - depends on CIFS && KEYS - help - Enables an upcall mechanism for CIFS which accesses - userspace helper utilities to provide SPNEGO packaged (RFC 4178) - Kerberos tickets which are needed to mount to certain secure servers - (for which more secure Kerberos authentication is required). If - unsure, say N. + bool "Kerberos/SPNEGO advanced session setup" + depends on CIFS && KEYS + select DNS_RESOLVER + help + Enables an upcall mechanism for CIFS which accesses userspace helper + utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets + which are needed to mount to certain secure servers (for which more + secure Kerberos authentication is required). If unsure, say N. config CIFS_XATTR bool "CIFS extended attributes" @@ -122,6 +122,7 @@ config CIFS_DEBUG2 config CIFS_DFS_UPCALL bool "DFS feature support" depends on CIFS && KEYS + select DNS_RESOLVER help Distributed File System (DFS) support is used to access shares transparently in an enterprise name space, even if the share diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 8a2cf129e535..2a0c892959f4 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -45,7 +45,6 @@ #include "cifs_fs_sb.h" #include #include -#include "dns_resolve.h" #include "cifs_spnego.h" #include "fscache.h" #define CIFS_MAGIC_NUMBER 0xFF534D42 /* the first four bytes of SMB PDUs */ @@ -933,23 +932,14 @@ init_cifs(void) rc = register_key_type(&cifs_spnego_key_type); if (rc) goto out_unregister_filesystem; -#endif -#ifdef CONFIG_CIFS_DFS_UPCALL - rc = cifs_init_dns_resolver(); - if (rc) - goto out_unregister_key_type; #endif rc = slow_work_register_user(THIS_MODULE); if (rc) - goto out_unregister_resolver_key; + goto out_unregister_key_type; return 0; - out_unregister_resolver_key: -#ifdef CONFIG_CIFS_DFS_UPCALL - cifs_exit_dns_resolver(); out_unregister_key_type: -#endif #ifdef CONFIG_CIFS_UPCALL unregister_key_type(&cifs_spnego_key_type); out_unregister_filesystem: @@ -976,7 +966,6 @@ exit_cifs(void) cifs_fscache_unregister(); #ifdef CONFIG_CIFS_DFS_UPCALL cifs_dfs_release_automount_timer(); - cifs_exit_dns_resolver(); #endif #ifdef CONFIG_CIFS_UPCALL unregister_key_type(&cifs_spnego_key_type); diff --git a/fs/cifs/dns_resolve.c b/fs/cifs/dns_resolve.c index aa967e7917f8..0eb87026cad3 100644 --- a/fs/cifs/dns_resolve.c +++ b/fs/cifs/dns_resolve.c @@ -4,6 +4,8 @@ * Copyright (c) 2007 Igor Mammedov * Author(s): Igor Mammedov (niallain@gmail.com) * Steve French (sfrench@us.ibm.com) + * Wang Lei (wang840925@gmail.com) + * David Howells (dhowells@redhat.com) * * Contains the CIFS DFS upcall routines used for hostname to * IP address translation. @@ -24,212 +26,73 @@ */ #include -#include -#include -#include +#include #include "dns_resolve.h" #include "cifsglob.h" #include "cifsproto.h" #include "cifs_debug.h" -static const struct cred *dns_resolver_cache; - -/* Checks if supplied name is IP address - * returns: - * 1 - name is IP - * 0 - name is not IP - */ -static int -is_ip(const char *name, int len) -{ - struct sockaddr_storage ss; - - return cifs_convert_address((struct sockaddr *)&ss, name, len); -} - -static int -dns_resolver_instantiate(struct key *key, const void *data, - size_t datalen) -{ - 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; - - memcpy(ip, data, datalen); - ip[datalen] = '\0'; - - key->type_data.x[0] = datalen; - key->payload.data = ip; - - return rc; -} - -static void -dns_resolver_destroy(struct key *key) -{ - kfree(key->payload.data); -} - -struct key_type key_type_dns_resolver = { - .name = "dns_resolver", - .def_datalen = sizeof(struct in_addr), - .describe = user_describe, - .instantiate = dns_resolver_instantiate, - .destroy = dns_resolver_destroy, - .match = user_match, -}; - -/* Resolves server name to ip address. - * input: - * unc - server UNC - * output: - * *ip_addr - pointer to server ip, caller responcible for freeing it. - * return the length of the returned string on success +/** + * dns_resolve_server_name_to_ip - Resolve UNC server name to ip address. + * @unc: UNC path specifying the server + * @ip_addr: Where to return the IP address. + * + * The IP address will be returned in string form, and the caller is + * responsible for freeing it. + * + * Returns length of result on success, -ve on error. */ int dns_resolve_server_name_to_ip(const char *unc, char **ip_addr) { - const struct cred *saved_cred; - int rc = -EAGAIN; - struct key *rkey = ERR_PTR(-EAGAIN); + struct sockaddr_storage ss; + const char *hostname, *sep; char *name; - char *data = NULL; - int len; + int len, rc; if (!ip_addr || !unc) return -EINVAL; - /* search for server name delimiter */ len = strlen(unc); if (len < 3) { cFYI(1, "%s: unc is too short: %s", __func__, unc); return -EINVAL; } + + /* Discount leading slashes for cifs */ len -= 2; - name = memchr(unc+2, '\\', len); - if (!name) { + hostname = unc + 2; + + /* Search for server name delimiter */ + sep = memchr(hostname, '\\', len); + if (sep) + len = sep - unc; + else cFYI(1, "%s: probably server name is whole unc: %s", - __func__, unc); - } else { - len = (name - unc) - 2/* leading // */; - } + __func__, unc); - name = kmalloc(len+1, GFP_KERNEL); - if (!name) { - rc = -ENOMEM; - return rc; - } - memcpy(name, unc+2, len); - name[len] = 0; + /* Try to interpret hostname as an IPv4 or IPv6 address */ + rc = cifs_convert_address((struct sockaddr *)&ss, hostname, len); + if (rc > 0) + goto name_is_IP_address; - if (is_ip(name, len)) { - cFYI(1, "%s: it is IP, skipping dns upcall: %s", - __func__, name); - data = name; - goto skip_upcall; - } - - saved_cred = override_creds(dns_resolver_cache); - rkey = request_key(&key_type_dns_resolver, name, ""); - revert_creds(saved_cred); - if (!IS_ERR(rkey)) { - if (!(rkey->perm & KEY_USR_VIEW)) { - down_read(&rkey->sem); - rkey->perm |= KEY_USR_VIEW; - up_read(&rkey->sem); - } - len = rkey->type_data.x[0]; - data = rkey->payload.data; - } else { - cERROR(1, "%s: unable to resolve: %s", __func__, name); - goto out; - } - -skip_upcall: - if (data) { - *ip_addr = kmalloc(len + 1, GFP_KERNEL); - if (*ip_addr) { - memcpy(*ip_addr, data, len + 1); - if (!IS_ERR(rkey)) - cFYI(1, "%s: resolved: %s to %s", __func__, - name, - *ip_addr - ); - rc = len; - } else { - rc = -ENOMEM; - } - if (!IS_ERR(rkey)) - key_put(rkey); - } - -out: - kfree(name); + /* Perform the upcall */ + rc = dns_query(NULL, hostname, len, NULL, ip_addr, NULL); + if (rc < 0) + cERROR(1, "%s: unable to resolve: %*.*s", + __func__, len, len, hostname); + else + cFYI(1, "%s: resolved: %*.*s to %s", + __func__, len, len, hostname, *ip_addr); return rc; -} -int __init cifs_init_dns_resolver(void) -{ - struct cred *cred; - struct key *keyring; - int ret; - - printk(KERN_NOTICE "Registering the %s key type\n", - key_type_dns_resolver.name); - - /* create an override credential set with a special thread keyring in - * which DNS requests are cached - * - * this is used to prevent malicious redirections from being installed - * with add_key(). - */ - cred = prepare_kernel_cred(NULL); - if (!cred) +name_is_IP_address: + name = kmalloc(len + 1, GFP_KERNEL); + if (!name) return -ENOMEM; - - keyring = key_alloc(&key_type_keyring, ".dns_resolver", 0, 0, cred, - (KEY_POS_ALL & ~KEY_POS_SETATTR) | - KEY_USR_VIEW | KEY_USR_READ, - KEY_ALLOC_NOT_IN_QUOTA); - if (IS_ERR(keyring)) { - ret = PTR_ERR(keyring); - goto failed_put_cred; - } - - ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL); - if (ret < 0) - goto failed_put_key; - - ret = register_key_type(&key_type_dns_resolver); - if (ret < 0) - goto failed_put_key; - - /* instruct request_key() to use this special keyring as a cache for - * the results it looks up */ - cred->thread_keyring = keyring; - cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING; - dns_resolver_cache = cred; + memcpy(name, hostname, len); + name[len] = 0; + cFYI(1, "%s: unc is IP, skipping dns upcall: %s", __func__, name); + *ip_addr = name; return 0; - -failed_put_key: - key_put(keyring); -failed_put_cred: - put_cred(cred); - return ret; -} - -void cifs_exit_dns_resolver(void) -{ - key_revoke(dns_resolver_cache->thread_keyring); - unregister_key_type(&key_type_dns_resolver); - put_cred(dns_resolver_cache); - printk(KERN_NOTICE "Unregistered %s key type\n", - key_type_dns_resolver.name); } diff --git a/fs/cifs/dns_resolve.h b/fs/cifs/dns_resolve.h index 5d7f291df162..d3f5d27f4d06 100644 --- a/fs/cifs/dns_resolve.h +++ b/fs/cifs/dns_resolve.h @@ -24,8 +24,6 @@ #define _DNS_RESOLVE_H #ifdef __KERNEL__ -extern int __init cifs_init_dns_resolver(void); -extern void cifs_exit_dns_resolver(void); extern int dns_resolve_server_name_to_ip(const char *unc, char **ip_addr); #endif /* KERNEL */ diff --git a/include/keys/dns_resolver-type.h b/include/keys/dns_resolver-type.h new file mode 100644 index 000000000000..9284a19393aa --- /dev/null +++ b/include/keys/dns_resolver-type.h @@ -0,0 +1,23 @@ +/* DNS resolver key type + * + * Copyright (C) 2010 Wang Lei. All Rights Reserved. + * Written by Wang Lei (wang840925@gmail.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#ifndef _KEYS_DNS_RESOLVER_TYPE_H +#define _KEYS_DNS_RESOLVER_TYPE_H + +#include + +extern struct key_type key_type_dns_resolver; + +extern int request_dns_resolver_key(const char *description, + const char *callout_info, + char **data); + +#endif /* _KEYS_DNS_RESOLVER_TYPE_H */ diff --git a/include/linux/dns_resolver.h b/include/linux/dns_resolver.h new file mode 100644 index 000000000000..cc92268af89a --- /dev/null +++ b/include/linux/dns_resolver.h @@ -0,0 +1,34 @@ +/* + * DNS Resolver upcall management for CIFS DFS and AFS + * Handles host name to IP address resolution and DNS query for AFSDB RR. + * + * Copyright (c) International Business Machines Corp., 2008 + * Author(s): Steve French (sfrench@us.ibm.com) + * Wang Lei (wang840925@gmail.com) + * + * This library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published + * by the Free Software Foundation; either version 2.1 of the License, or + * (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef _LINUX_DNS_RESOLVER_H +#define _LINUX_DNS_RESOLVER_H + +#ifdef __KERNEL__ + +extern int dns_query(const char *type, const char *name, size_t namelen, + const char *options, char **_result, time_t *_expiry); + +#endif /* KERNEL */ + +#endif /* _LINUX_DNS_RESOLVER_H */ diff --git a/net/Kconfig b/net/Kconfig index e24fa0873f32..e330594d3709 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -213,6 +213,7 @@ source "net/phonet/Kconfig" source "net/ieee802154/Kconfig" source "net/sched/Kconfig" source "net/dcb/Kconfig" +source "net/dns_resolver/Kconfig" config RPS boolean diff --git a/net/Makefile b/net/Makefile index 41d420070a38..ea60fbce9b1b 100644 --- a/net/Makefile +++ b/net/Makefile @@ -67,3 +67,4 @@ ifeq ($(CONFIG_NET),y) obj-$(CONFIG_SYSCTL) += sysctl_net.o endif obj-$(CONFIG_WIMAX) += wimax/ +obj-$(CONFIG_DNS_RESOLVER) += dns_resolver/ diff --git a/net/dns_resolver/Kconfig b/net/dns_resolver/Kconfig new file mode 100644 index 000000000000..2ec47cb5d0d6 --- /dev/null +++ b/net/dns_resolver/Kconfig @@ -0,0 +1,27 @@ +# +# Configuration for DNS Resolver +# +config DNS_RESOLVER + tristate "DNS Resolver support" + depends on NET && KEYS + help + Saying Y here will include support for the DNS Resolver key type + which can be used to make upcalls to perform DNS lookups in + userspace. + + DNS Resolver is used to query DNS server for information. Examples + being resolving a UNC hostname element to an IP address for CIFS or + performing a DNS query for AFSDB records so that AFS can locate a + cell's volume location database servers. + + DNS Resolver is used by the CIFS and AFS modules, and would support + samba4 later. DNS Resolver is supported by the userspace upcall + helper "/sbin/dns.resolver" via /etc/request-key.conf. + + See for further + information. + + To compile this as a module, choose M here: the module will be called + dnsresolver. + + If unsure, say N. diff --git a/net/dns_resolver/Makefile b/net/dns_resolver/Makefile new file mode 100644 index 000000000000..c0ef4e71dc49 --- /dev/null +++ b/net/dns_resolver/Makefile @@ -0,0 +1,7 @@ +# +# Makefile for the Linux DNS Resolver. +# + +obj-$(CONFIG_DNS_RESOLVER) += dns_resolver.o + +dns_resolver-objs := dns_key.o dns_query.o diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c new file mode 100644 index 000000000000..1b1b411adcf1 --- /dev/null +++ b/net/dns_resolver/dns_key.c @@ -0,0 +1,210 @@ +/* Key type used to cache DNS lookups made by the kernel + * + * See Documentation/networking/dns_resolver.txt + * + * Copyright (c) 2007 Igor Mammedov + * Author(s): Igor Mammedov (niallain@gmail.com) + * Steve French (sfrench@us.ibm.com) + * Wang Lei (wang840925@gmail.com) + * David Howells (dhowells@redhat.com) + * + * This library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published + * by the Free Software Foundation; either version 2.1 of the License, or + * (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +MODULE_DESCRIPTION("DNS Resolver"); +MODULE_AUTHOR("Wang Lei"); +MODULE_LICENSE("GPL"); + +unsigned dns_resolver_debug; +module_param_named(debug, dns_resolver_debug, uint, S_IWUSR | S_IRUGO); +MODULE_PARM_DESC(debug, "DNS Resolver debugging mask"); + +const struct cred *dns_resolver_cache; + +/* + * Instantiate a user defined key for dns_resolver. + * + * The data must be a NUL-terminated string, with the NUL char accounted in + * datalen. + * + * If the data contains a '#' characters, then we take the clause after each + * one to be an option of the form 'key=value'. The actual data of interest is + * the string leading up to the first '#'. For instance: + * + * "ip1,ip2,...#foo=bar" + */ +static int +dns_resolver_instantiate(struct key *key, const void *_data, size_t datalen) +{ + struct user_key_payload *upayload; + int ret; + size_t result_len = 0; + const char *data = _data, *opt; + + kenter("%%%d,%s,'%s',%zu", + key->serial, key->description, data, datalen); + + if (datalen <= 1 || !data || data[datalen - 1] != '\0') + return -EINVAL; + datalen--; + + /* deal with any options embedded in the data */ + opt = memchr(data, '#', datalen); + if (!opt) { + kdebug("no options currently supported"); + return -EINVAL; + } + + result_len = datalen; + ret = key_payload_reserve(key, result_len); + if (ret < 0) + return -EINVAL; + + upayload = kmalloc(sizeof(*upayload) + result_len + 1, GFP_KERNEL); + if (!upayload) { + kleave(" = -ENOMEM"); + return -ENOMEM; + } + + upayload->datalen = result_len; + memcpy(upayload->data, data, result_len); + upayload->data[result_len] = '\0'; + rcu_assign_pointer(key->payload.data, upayload); + + kleave(" = 0"); + return 0; +} + +/* + * The description is of the form "[:]" + * + * The domain name may be a simple name or an absolute domain name (which + * should end with a period). The domain name is case-independent. + */ +static int +dns_resolver_match(const struct key *key, const void *description) +{ + int slen, dlen, ret = 0; + const char *src = key->description, *dsp = description; + + kenter("%s,%s", src, dsp); + + if (!src || !dsp) + goto no_match; + + if (strcasecmp(src, dsp) == 0) + goto matched; + + slen = strlen(src); + dlen = strlen(dsp); + if (slen <= 0 || dlen <= 0) + goto no_match; + if (src[slen - 1] == '.') + slen--; + if (dsp[dlen - 1] == '.') + dlen--; + if (slen != dlen || strncasecmp(src, dsp, slen) != 0) + goto no_match; + +matched: + ret = 1; +no_match: + kleave(" = %d", ret); + return ret; +} + +struct key_type key_type_dns_resolver = { + .name = "dns_resolver", + .instantiate = dns_resolver_instantiate, + .match = dns_resolver_match, + .revoke = user_revoke, + .destroy = user_destroy, + .describe = user_describe, + .read = user_read, +}; + +static int __init init_dns_resolver(void) +{ + struct cred *cred; + struct key *keyring; + int ret; + + printk(KERN_NOTICE "Registering the %s key type\n", + key_type_dns_resolver.name); + + /* create an override credential set with a special thread keyring in + * which DNS requests are cached + * + * this is used to prevent malicious redirections from being installed + * with add_key(). + */ + cred = prepare_kernel_cred(NULL); + if (!cred) + return -ENOMEM; + + keyring = key_alloc(&key_type_keyring, ".dns_resolver", 0, 0, cred, + (KEY_POS_ALL & ~KEY_POS_SETATTR) | + KEY_USR_VIEW | KEY_USR_READ, + KEY_ALLOC_NOT_IN_QUOTA); + if (IS_ERR(keyring)) { + ret = PTR_ERR(keyring); + goto failed_put_cred; + } + + ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL); + if (ret < 0) + goto failed_put_key; + + ret = register_key_type(&key_type_dns_resolver); + if (ret < 0) + goto failed_put_key; + + /* instruct request_key() to use this special keyring as a cache for + * the results it looks up */ + cred->thread_keyring = keyring; + cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING; + dns_resolver_cache = cred; + + kdebug("DNS resolver keyring: %d\n", key_serial(keyring)); + return 0; + +failed_put_key: + key_put(keyring); +failed_put_cred: + put_cred(cred); + return ret; +} + +static void __exit exit_dns_resolver(void) +{ + key_revoke(dns_resolver_cache->thread_keyring); + unregister_key_type(&key_type_dns_resolver); + put_cred(dns_resolver_cache); + printk(KERN_NOTICE "Unregistered %s key type\n", + key_type_dns_resolver.name); +} + +module_init(init_dns_resolver) +module_exit(exit_dns_resolver) +MODULE_LICENSE("GPL"); diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c new file mode 100644 index 000000000000..6c0cf31ea00d --- /dev/null +++ b/net/dns_resolver/dns_query.c @@ -0,0 +1,159 @@ +/* Upcall routine, designed to work as a key type and working through + * /sbin/request-key to contact userspace when handling DNS queries. + * + * See Documentation/networking/dns_resolver.txt + * + * Copyright (c) 2007 Igor Mammedov + * Author(s): Igor Mammedov (niallain@gmail.com) + * Steve French (sfrench@us.ibm.com) + * Wang Lei (wang840925@gmail.com) + * David Howells (dhowells@redhat.com) + * + * The upcall wrapper used to make an arbitrary DNS query. + * + * This function requires the appropriate userspace tool dns.upcall to be + * installed and something like the following lines should be added to the + * /etc/request-key.conf file: + * + * create dns_resolver * * /sbin/dns.upcall %k + * + * For example to use this module to query AFSDB RR: + * + * create dns_resolver afsdb:* * /sbin/dns.afsdb %k + * + * This library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published + * by the Free Software Foundation; either version 2.1 of the License, or + * (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include + +#include "internal.h" + +/* + * dns_query - Query the DNS + * @type: Query type (or NULL for straight host->IP lookup) + * @name: Name to look up + * @namelen: Length of name + * @options: Request options (or NULL if no options) + * @_result: Where to place the returned data. + * @_expiry: Where to store the result expiry time (or NULL) + * + * The data will be returned in the pointer at *result, and the caller is + * responsible for freeing it. + * + * The description should be of the form "[:]", and + * the options need to be appropriate for the query type requested. If no + * query_type is given, then the query is a straight hostname to IP address + * lookup. + * + * The DNS resolution lookup is performed by upcalling to userspace by way of + * requesting a key of type dns_resolver. + * + * Returns the size of the result on success, -ve error code otherwise. + */ +int dns_query(const char *type, const char *name, size_t namelen, + const char *options, char **_result, time_t *_expiry) +{ + struct key *rkey; + struct user_key_payload *upayload; + const struct cred *saved_cred; + size_t typelen, desclen; + char *desc, *cp; + int ret, len; + + kenter("%s,%*.*s,%zu,%s", + type, (int)namelen, (int)namelen, name, namelen, options); + + if (!name || namelen == 0 || !_result) + return -EINVAL; + + /* construct the query key description as "[:]" */ + typelen = 0; + desclen = 0; + if (type) { + typelen = strlen(type); + if (typelen < 1) + return -EINVAL; + desclen += typelen + 1; + } + + if (!namelen) + namelen = strlen(name); + if (namelen < 3) + return -EINVAL; + desclen += namelen + 1; + + desc = kmalloc(desclen, GFP_KERNEL); + if (!desc) + return -ENOMEM; + + cp = desc; + if (type) { + memcpy(cp, type, typelen); + cp += typelen; + *cp++ = ':'; + } + memcpy(cp, name, namelen); + cp += namelen; + *cp = '\0'; + + if (!options) + options = ""; + kdebug("call request_key(,%s,%s)", desc, options); + + /* make the upcall, using special credentials to prevent the use of + * add_key() to preinstall malicious redirections + */ + saved_cred = override_creds(dns_resolver_cache); + rkey = request_key(&key_type_dns_resolver, desc, options); + revert_creds(saved_cred); + kfree(desc); + if (IS_ERR(rkey)) { + ret = PTR_ERR(rkey); + goto out; + } + + down_read(&rkey->sem); + rkey->perm |= KEY_USR_VIEW; + + ret = key_validate(rkey); + if (ret < 0) + goto put; + + upayload = rcu_dereference_protected(rkey->payload.data, + lockdep_is_held(&rkey->sem)); + len = upayload->datalen; + + ret = -ENOMEM; + *_result = kmalloc(len + 1, GFP_KERNEL); + if (!*_result) + goto put; + + memcpy(*_result, upayload->data, len + 1); + if (_expiry) + *_expiry = rkey->expiry; + + ret = len; +put: + up_read(&rkey->sem); + key_put(rkey); +out: + kleave(" = %d", ret); + return ret; +} +EXPORT_SYMBOL(dns_query); diff --git a/net/dns_resolver/internal.h b/net/dns_resolver/internal.h new file mode 100644 index 000000000000..189ca9e9b785 --- /dev/null +++ b/net/dns_resolver/internal.h @@ -0,0 +1,44 @@ +/* + * Copyright (c) 2010 Wang Lei + * Author(s): Wang Lei (wang840925@gmail.com). All Rights Reserved. + * + * Internal DNS Rsolver stuff + * + * This library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published + * by the Free Software Foundation; either version 2.1 of the License, or + * (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include + +/* + * dns_key.c + */ +extern const struct cred *dns_resolver_cache; + +/* + * debug tracing + */ +extern unsigned dns_resolver_debug; + +#define kdebug(FMT, ...) \ +do { \ + if (unlikely(dns_resolver_debug)) \ + printk(KERN_DEBUG "[%-6.6s] "FMT"\n", \ + current->comm, ##__VA_ARGS__); \ +} while (0) + +#define kenter(FMT, ...) kdebug("==> %s("FMT")", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) kdebug("<== %s()"FMT"", __func__, ##__VA_ARGS__) From 07567a5509327bcbf2c867286eb1524447c9b954 Mon Sep 17 00:00:00 2001 From: Wang Lei Date: Wed, 4 Aug 2010 15:16:38 +0100 Subject: [PATCH 07/10] DNS: Make AFS go to the DNS for AFSDB records for unknown cells Add DNS query support for AFS so that it can get the IP addresses of Volume Location servers from the DNS using an AFSDB record. This requires userspace support. /etc/request-key.conf must be configured to invoke a helper for dns_resolver type keys with a subtype of "afsdb:" in the description. Signed-off-by: Wang Lei Signed-off-by: David Howells Signed-off-by: Steve French --- fs/afs/Kconfig | 1 + fs/afs/cell.c | 40 ++++++++++++++++++++++++++++++---------- 2 files changed, 31 insertions(+), 10 deletions(-) diff --git a/fs/afs/Kconfig b/fs/afs/Kconfig index 5c4e61d3c772..8f975f25b486 100644 --- a/fs/afs/Kconfig +++ b/fs/afs/Kconfig @@ -2,6 +2,7 @@ config AFS_FS tristate "Andrew File System support (AFS) (EXPERIMENTAL)" depends on INET && EXPERIMENTAL select AF_RXRPC + select DNS_RESOLVER help If you say Y here, you will get an experimental Andrew File System driver. It currently only supports unsecured read-only AFS access. diff --git a/fs/afs/cell.c b/fs/afs/cell.c index e19c13f059ed..ffea35c63879 100644 --- a/fs/afs/cell.c +++ b/fs/afs/cell.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include "internal.h" @@ -36,6 +37,8 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist) struct key *key; size_t namelen; char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next; + char *dvllist = NULL, *_vllist = NULL; + char delimiter = ':'; int ret; _enter("%s,%s", name, vllist); @@ -43,8 +46,10 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist) BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */ namelen = strlen(name); - if (namelen > AFS_MAXCELLNAME) + if (namelen > AFS_MAXCELLNAME) { + _leave(" = -ENAMETOOLONG"); return ERR_PTR(-ENAMETOOLONG); + } /* allocate and initialise a cell record */ cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL); @@ -64,15 +69,31 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist) INIT_LIST_HEAD(&cell->vl_list); spin_lock_init(&cell->vl_lock); + /* if the ip address is invalid, try dns query */ + if (!vllist || strlen(vllist) < 7) { + ret = dns_query("afsdb", name, namelen, "ipv4", &dvllist, NULL); + if (ret < 0) { + _leave(" = %d", ret); + return ERR_PTR(ret); + } + _vllist = dvllist; + + /* change the delimiter for user-space reply */ + delimiter = ','; + + } else { + _vllist = vllist; + } + /* fill in the VL server list from the rest of the string */ do { unsigned a, b, c, d; - next = strchr(vllist, ':'); + next = strchr(_vllist, delimiter); if (next) *next++ = 0; - if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4) + if (sscanf(_vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4) goto bad_address; if (a > 255 || b > 255 || c > 255 || d > 255) @@ -81,7 +102,7 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist) cell->vl_addrs[cell->vl_naddrs++].s_addr = htonl((a << 24) | (b << 16) | (c << 8) | d); - } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (vllist = next)); + } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (_vllist = next)); /* create a key to represent an anonymous user */ memcpy(keyname, "afs@", 4); @@ -110,6 +131,7 @@ bad_address: ret = -EINVAL; error: key_put(cell->anonymous_key); + kfree(dvllist); kfree(cell); _leave(" = %d", ret); return ERR_PTR(ret); @@ -201,14 +223,12 @@ int afs_cell_init(char *rootcell) } cp = strchr(rootcell, ':'); - if (!cp) { - printk(KERN_ERR "kAFS: no VL server IP addresses specified\n"); - _leave(" = -EINVAL"); - return -EINVAL; - } + if (!cp) + _debug("kAFS: no VL server IP addresses specified"); + else + *cp++ = 0; /* allocate a cell record for the root cell */ - *cp++ = 0; new_root = afs_cell_create(rootcell, cp); if (IS_ERR(new_root)) { _leave(" = %ld", PTR_ERR(new_root)); From af352fe960263fbab3252be0ba6d4e0a27e62f5d Mon Sep 17 00:00:00 2001 From: Stephen Rothwell Date: Fri, 6 Aug 2010 03:13:47 +0100 Subject: [PATCH 08/10] cifs: Include linux/err.h for IS_ERR and PTR_ERR Fixes build errors: net/dns_resolver/dns_key.c: In function 'init_dns_resolver': net/dns_resolver/dns_key.c:170: error: implicit declaration of function 'IS_ERR' net/dns_resolver/dns_key.c:171: error: implicit declaration of function 'PTR_ERR' net/dns_resolver/dns_query.c: In function 'dns_query': net/dns_resolver/dns_query.c:126: error: implicit declaration of function 'IS_ERR' net/dns_resolver/dns_query.c:127: error: implicit declaration of function 'PTR_ERR' Signed-off-by: Stephen Rothwell Signed-off-by: David Howells Signed-off-by: Steve French --- net/dns_resolver/dns_key.c | 1 + net/dns_resolver/dns_query.c | 1 + 2 files changed, 2 insertions(+) diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c index 1b1b411adcf1..400a04d5c9a1 100644 --- a/net/dns_resolver/dns_key.c +++ b/net/dns_resolver/dns_key.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include #include "internal.h" diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c index 6c0cf31ea00d..b33e1f7ff48d 100644 --- a/net/dns_resolver/dns_query.c +++ b/net/dns_resolver/dns_query.c @@ -39,6 +39,7 @@ #include #include #include +#include #include #include From ff9517a68792bb363c16f4e3155c4fc5a7f9d738 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 6 Aug 2010 03:13:52 +0100 Subject: [PATCH 09/10] DNS: Fixes for the DNS query module Fixes for the DNS query module, including: (1) Use 'negative' instead of '-ve' in the documentation. (2) Mark the kdoc comment with '/**' on dns_query(). Reported-by: Randy Dunlap Signed-off-by: David Howells Signed-off-by: Steve French --- Documentation/networking/dns_resolver.txt | 6 +++--- net/dns_resolver/dns_query.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/Documentation/networking/dns_resolver.txt b/Documentation/networking/dns_resolver.txt index d8e0ce1d38c7..aefd1e681804 100644 --- a/Documentation/networking/dns_resolver.txt +++ b/Documentation/networking/dns_resolver.txt @@ -96,9 +96,9 @@ implemented in the module can be called after doing: for the default query type it is just a list of comma-separated IPv4 and IPv6 addresses. The caller must free the result. - The length of the result string is returned on success, and a -ve error - code is returned otherwise. -EKEYREJECTED will be returned if the DNS - lookup failed. + The length of the result string is returned on success, and a negative + error code is returned otherwise. -EKEYREJECTED will be returned if the + DNS lookup failed. If _expiry is non-NULL, the expiry time (TTL) of the result will be returned also. diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c index b33e1f7ff48d..03d5255f5cf2 100644 --- a/net/dns_resolver/dns_query.c +++ b/net/dns_resolver/dns_query.c @@ -45,7 +45,7 @@ #include "internal.h" -/* +/** * dns_query - Query the DNS * @type: Query type (or NULL for straight host->IP lookup) * @name: Name to look up From 5227bbb008fa6d2efddd86170bdfac2020cf571d Mon Sep 17 00:00:00 2001 From: Steve French Date: Fri, 6 Aug 2010 03:18:09 +0000 Subject: [PATCH 10/10] [DNS RESOLVER] Minor typo correction CC: Dave Howells Signed-off-by: Steve French --- net/dns_resolver/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/dns_resolver/Kconfig b/net/dns_resolver/Kconfig index 2ec47cb5d0d6..50d49f7e0472 100644 --- a/net/dns_resolver/Kconfig +++ b/net/dns_resolver/Kconfig @@ -15,7 +15,7 @@ config DNS_RESOLVER cell's volume location database servers. DNS Resolver is used by the CIFS and AFS modules, and would support - samba4 later. DNS Resolver is supported by the userspace upcall + SMB2 later. DNS Resolver is supported by the userspace upcall helper "/sbin/dns.resolver" via /etc/request-key.conf. See for further