On Fri, Jan 6, 2012 at 7:11 AM, Jeff Layton <[email protected]> wrote:
> Fix up multiuser mounts to set the secType and set the username and
> password from the key payload in the vol info for non-krb5 auth types.
>
> Look for a key of type "secret" with a description of
> "cifs:a:<server address>" or "cifs:d:<domainname>". If that's found,
> then scrape the username and password out of the key payload and use
> that to create a new user session.
>
> Finally, don't have the code enforce krb5 auth on multiuser mounts,
> but do require a kernel with keys support.
>
> Signed-off-by: Jeff Layton <[email protected]>
> ---
> fs/cifs/connect.c | 176
> ++++++++++++++++++++++++++++++++++++++++++++++++++---
> 1 files changed, 166 insertions(+), 10 deletions(-)
>
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 5e96e60..48f2d15 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -38,6 +38,7 @@
> #include <asm/processor.h>
> #include <linux/inet.h>
> #include <linux/module.h>
> +#include <keys/user-type.h>
> #include <net/ipv6.h>
> #include "cifspdu.h"
> #include "cifsglob.h"
> @@ -1594,11 +1595,14 @@ cifs_parse_mount_options(const char *mountdata, const
> char *devname,
> }
> }
>
> - if (vol->multiuser && !(vol->secFlg & CIFSSEC_MAY_KRB5)) {
> - cERROR(1, "Multiuser mounts currently require krb5 "
> - "authentication!");
> +#ifndef CONFIG_KEYS
> + /* Muliuser mounts require CONFIG_KEYS support */
> + if (vol->multiuser) {
> + cERROR(1, "Multiuser mounts require kernels with "
> + "CONFIG_KEYS enabled.");
> goto cifs_parse_mount_err;
> }
> +#endif
Will this break existing setups when those users update kernel
and/or update cifs module?
>
> if (vol->UNCip == NULL)
> vol->UNCip = &vol->UNC[2];
> @@ -2061,6 +2065,133 @@ cifs_put_smb_ses(struct cifs_ses *ses)
> cifs_put_tcp_session(server);
> }
>
> +#ifdef CONFIG_KEYS
> +
> +/* strlen("cifs:a:") + INET6_ADDRSTRLEN + 1 */
> +#define CIFSCREDS_DESC_SIZE (7 + INET6_ADDRSTRLEN + 1)
> +
> +/* Populate username and pw fields from keyring if possible */
> +static int
> +cifs_set_cifscreds(struct smb_vol *vol, struct cifs_ses *ses)
> +{
> + int rc = 0;
> + char *desc, *delim, *payload;
> + ssize_t len;
> + struct key *key;
> + struct TCP_Server_Info *server = ses->server;
> + struct sockaddr_in *sa;
> + struct sockaddr_in6 *sa6;
> + struct user_key_payload *upayload;
> +
> + desc = kmalloc(CIFSCREDS_DESC_SIZE, GFP_KERNEL);
> + if (!desc)
> + return -ENOMEM;
> +
> + /* try to find an address key first */
> + switch (server->dstaddr.ss_family) {
> + case AF_INET:
> + sa = (struct sockaddr_in *)&server->dstaddr;
> + sprintf(desc, "cifs:a:%pI4", &sa->sin_addr.s_addr);
> + break;
> + case AF_INET6:
> + sa6 = (struct sockaddr_in6 *)&server->dstaddr;
> + sprintf(desc, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
> + break;
> + default:
> + cFYI(1, "Bad ss_family (%hu)", server->dstaddr.ss_family);
> + rc = -EINVAL;
> + goto out_err;
> + }
> +
> + cFYI(1, "%s: desc=%s", __func__, desc);
> + key = request_key(&key_type_secret, desc, "");
> + if (IS_ERR(key)) {
> + if (!ses->domainName) {
> + cFYI(1, "domainName is NULL");
> + rc = PTR_ERR(key);
> + goto out_err;
> + }
> +
> + /* didn't work, try to find a domain key */
> + sprintf(desc, "cifs:d:%s", ses->domainName);
> + cFYI(1, "%s: desc=%s", __func__, desc);
> + key = request_key(&key_type_secret, desc, "");
> + if (IS_ERR(key)) {
> + rc = PTR_ERR(key);
> + goto out_err;
> + }
> + }
> +
> + down_read(&key->sem);
> + upayload = key->payload.data;
> + if (IS_ERR_OR_NULL(upayload)) {
> + rc = PTR_ERR(key);
> + goto out_key_put;
> + }
> +
> + /* find first : in payload */
> + payload = (char *)upayload->data;
> + delim = strnchr(payload, upayload->datalen, ':');
> + cFYI(1, "payload=%s", payload);
> + if (!delim) {
> + cFYI(1, "Unable to find ':' in payload (datalen=%d)",
> + upayload->datalen);
> + rc = -EINVAL;
> + goto out_key_put;
> + }
> +
> + len = delim - payload;
> + if (len > MAX_USERNAME_SIZE || len <= 0) {
> + cFYI(1, "Bad value from username search (len=%ld)", len);
> + rc = -EINVAL;
> + goto out_key_put;
> + }
> +
> + vol->username = kstrndup(payload, len, GFP_KERNEL);
> + if (!vol->username) {
> + cFYI(1, "Unable to allocate %ld bytes for username", len);
> + rc = -ENOMEM;
> + goto out_key_put;
> + }
> + cFYI(1, "username=%s", vol->username);
> +
> + len = key->datalen - (len + 1);
> + if (len > MAX_PASSWORD_SIZE || len <= 0) {
> + cFYI(1, "Bad len for password search (len=%ld)", len);
> + rc = -EINVAL;
> + kfree(vol->username);
> + vol->username = NULL;
> + goto out_key_put;
> + }
> +
> + ++delim;
> + vol->password = kstrndup(delim, len, GFP_KERNEL);
> + if (!vol->password) {
> + cFYI(1, "Unable to allocate %ld bytes for password", len);
> + rc = -ENOMEM;
> + kfree(vol->username);
> + vol->username = NULL;
> + goto out_key_put;
> + }
> + cFYI(1, "password=%s", vol->password);
I would be wary of printing the password.
> +
> +out_key_put:
> + up_read(&key->sem);
> + key_put(key);
> +out_err:
> + kfree(desc);
> + cFYI(1, "%s: returning %d", __func__, rc);
> + return rc;
> +}
> +#else /* ! CONFIG_KEYS */
> +static inline int
> +cifs_set_cifscreds(struct smb_vol *vol __attribute__((unused)),
> + struct cifs_ses *ses __attribute__((unused)))
> +{
> + return -ENOSYS;
> +}
> +#endif /* CONFIG_KEYS */
> +
> static bool warned_on_ntlm; /* globals init to false automatically */
>
> static struct cifs_ses *
> @@ -3678,16 +3809,38 @@ int cifs_setup_session(unsigned int xid, struct
> cifs_ses *ses,
> return rc;
> }
>
> +static int
> +cifs_set_vol_auth(struct smb_vol *vol, struct cifs_ses *ses)
> +{
> + switch(ses->server->secType) {
> + case Kerberos:
> + vol->secFlg = CIFSSEC_MUST_KRB5;
> + return 0;
> + case NTLMv2:
> + vol->secFlg = CIFSSEC_MUST_NTLMV2;
> + break;
> + case NTLM:
> + vol->secFlg = CIFSSEC_MUST_NTLM;
> + break;
> + case RawNTLMSSP:
> + vol->secFlg = CIFSSEC_MAY_NTLMSSP;
> + break;
> + case LANMAN:
> + vol->secFlg = CIFSSEC_MAY_LANMAN;
> + break;
> + }
> +
> + return cifs_set_cifscreds(vol, ses);
> +}
> +
> static struct cifs_tcon *
> cifs_construct_tcon(struct cifs_sb_info *cifs_sb, uid_t fsuid)
> {
> + int rc;
> struct cifs_tcon *master_tcon = cifs_sb_master_tcon(cifs_sb);
> struct cifs_ses *ses;
> struct cifs_tcon *tcon = NULL;
> struct smb_vol *vol_info;
> - char username[28]; /* big enough for "krb50x" + hex of ULONG_MAX 6+16
> */
> - /* We used to have this as MAX_USERNAME which is
> */
> - /* way too big now (256 instead of 32) */
>
> vol_info = kzalloc(sizeof(*vol_info), GFP_KERNEL);
> if (vol_info == NULL) {
> @@ -3695,8 +3848,6 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, uid_t
> fsuid)
> goto out;
> }
>
> - snprintf(username, sizeof(username), "krb50x%x", fsuid);
> - vol_info->username = username;
> vol_info->local_nls = cifs_sb->local_nls;
> vol_info->linux_uid = fsuid;
> vol_info->cred_uid = fsuid;
> @@ -3706,8 +3857,11 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb,
> uid_t fsuid)
> vol_info->local_lease = master_tcon->local_lease;
> vol_info->no_linux_ext = !master_tcon->unix_ext;
>
> - /* FIXME: allow for other secFlg settings */
> - vol_info->secFlg = CIFSSEC_MUST_KRB5;
> + rc = cifs_set_vol_auth(vol_info, master_tcon->ses);
> + if (rc) {
> + tcon = ERR_PTR(rc);
> + goto out;
> + }
>
> /* get a reference for the same TCP session */
> spin_lock(&cifs_tcp_ses_lock);
> @@ -3730,6 +3884,8 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, uid_t
> fsuid)
> if (ses->capabilities & CAP_UNIX)
> reset_cifs_unix_caps(0, tcon, NULL, vol_info);
> out:
> + kfree(vol_info->username);
> + kfree(vol_info->password);
> kfree(vol_info);
>
> return tcon;
> --
> 1.7.7.4
>
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