close - but not quite right.
cifsacl.c depends on CONFIG_CIFS_ACL, but you refer to functions in
cifsacl.c within a different ifdef in cifsfs.c
On Thu, Apr 21, 2011 at 9:15 AM, <shirishpargaonkar@xxxxxxxxx> wrote:
> From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>
> Define (global) data structures to store ids, uids and gids, to which a
> SID maps. There are two separate trees, one for SID/uid and another one
> for SID/gid.
>
> A new type of key, cifs_idmap_key_type, is used.
>
> Keys are instantiated and searched using credential of the root by
> overriding and restoring the credentials of the caller requesting the key.
>
> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/cifs/cifsacl.c | 138 +++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/cifs/cifsfs.c | 7 +++
> fs/cifs/cifsglob.h | 5 ++
> fs/cifs/cifsproto.h | 3 +
> 4 files changed, 153 insertions(+), 0 deletions(-)
>
> diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
> index a0d11ea..061fc3a 100644
> --- a/fs/cifs/cifsacl.c
> +++ b/fs/cifs/cifsacl.c
> @@ -23,6 +23,10 @@
>
> #include <linux/fs.h>
> #include <linux/slab.h>
> +#include <linux/string.h>
> +#include <linux/keyctl.h>
> +#include <linux/key-type.h>
> +#include <keys/user-type.h>
> #include "cifspdu.h"
> #include "cifsglob.h"
> #include "cifsacl.h"
> @@ -50,6 +54,140 @@ static const struct cifs_sid sid_authusers = {
> /* group users */
> static const struct cifs_sid sid_user = {1, 2 , {0, 0, 0, 0, 0, 5}, {} };
>
> +static const struct cred *root_cred;
> +
> +/*
> + * Run idmap cache shrinker.
> + */
> +static int
> +cifs_idmap_shrinker(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
> +{
> + /* Use a pruning scheme in a subsequent patch instead */
> + cifs_destroy_idmaptrees();
> + return 0;
> +}
> +
> +static struct shrinker cifs_shrinker = {
> + .shrink = cifs_idmap_shrinker,
> + .seeks = DEFAULT_SEEKS,
> +};
> +
> +static int
> +cifs_idmap_key_instantiate(struct key *key, const void *data, size_t datalen)
> +{
> + char *payload;
> +
> + payload = kmalloc(datalen, GFP_KERNEL);
> + if (!payload)
> + return -ENOMEM;
> +
> + memcpy(payload, data, datalen);
> + key->payload.data = payload;
> + return 0;
> +}
> +
> +static inline void
> +cifs_idmap_key_destroy(struct key *key)
> +{
> + kfree(key->payload.data);
> +}
> +
> +static
> +struct key_type cifs_idmap_key_type = {
> + .name = "cifs.cifs_idmap",
> + .instantiate = cifs_idmap_key_instantiate,
> + .destroy = cifs_idmap_key_destroy,
> + .describe = user_describe,
> + .match = user_match,
> +};
> +
> +int
> +init_cifs_idmap(void)
> +{
> + struct cred *cred;
> + struct key *keyring;
> + int ret;
> +
> + cFYI(1, "Registering the %s key type\n", cifs_idmap_key_type.name);
> +
> + /* create an override credential set with a special thread keyring in
> + * which 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, ".cifs_idmap", 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(&cifs_idmap_key_type);
> + 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;
> + root_cred = cred;
> +
> + spin_lock_init(&siduidlock);
> + uidtree = RB_ROOT;
> + spin_lock_init(&sidgidlock);
> + gidtree = RB_ROOT;
> +
> + register_shrinker(&cifs_shrinker);
> +
> + cFYI(1, "cifs idmap keyring: %d\n", key_serial(keyring));
> + return 0;
> +
> +failed_put_key:
> + key_put(keyring);
> +failed_put_cred:
> + put_cred(cred);
> + return ret;
> +}
> +
> +void
> +exit_cifs_idmap(void)
> +{
> + key_revoke(root_cred->thread_keyring);
> + unregister_key_type(&cifs_idmap_key_type);
> + put_cred(root_cred);
> + unregister_shrinker(&cifs_shrinker);
> + cFYI(1, "Unregistered %s key type\n", cifs_idmap_key_type.name);
> +}
> +
> +void
> +cifs_destroy_idmaptrees(void)
> +{
> + struct rb_root *root;
> + struct rb_node *node;
> +
> + root = &uidtree;
> + spin_lock(&siduidlock);
> + while ((node = rb_first(root)))
> + rb_erase(node, root);
> + spin_unlock(&siduidlock);
> +
> + root = &gidtree;
> + spin_lock(&sidgidlock);
> + while ((node = rb_first(root)))
> + rb_erase(node, root);
> + spin_unlock(&sidgidlock);
> +}
>
> int match_sid(struct cifs_sid *ctsid)
> {
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index 30fc505..665bf1d 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -1040,11 +1040,16 @@ init_cifs(void)
> rc = register_key_type(&cifs_spnego_key_type);
> if (rc)
> goto out_unregister_filesystem;
> + rc = init_cifs_idmap();
> + if (rc)
> + goto out_unregister_keytype;
> #endif
>
> return 0;
>
> #ifdef CONFIG_CIFS_UPCALL
> +out_unregister_keytype:
> + unregister_key_type(&cifs_spnego_key_type);
> out_unregister_filesystem:
> unregister_filesystem(&cifs_fs_type);
> #endif
> @@ -1071,6 +1076,8 @@ exit_cifs(void)
> cifs_dfs_release_automount_timer();
> #endif
> #ifdef CONFIG_CIFS_UPCALL
> + cifs_destroy_idmaptrees();
> + exit_cifs_idmap();
> unregister_key_type(&cifs_spnego_key_type);
> #endif
> unregister_filesystem(&cifs_fs_type);
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 108a1e9..76b4517 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -833,6 +833,11 @@ GLOBAL_EXTERN unsigned int cifs_max_pending; /* MAX requests at once to server*/
> /* reconnect after this many failed echo attempts */
> GLOBAL_EXTERN unsigned short echo_retries;
>
> +GLOBAL_EXTERN struct rb_root uidtree;
> +GLOBAL_EXTERN struct rb_root gidtree;
> +GLOBAL_EXTERN spinlock_t siduidlock;
> +GLOBAL_EXTERN spinlock_t sidgidlock;
> +
> void cifs_oplock_break(struct work_struct *work);
> void cifs_oplock_break_get(struct cifsFileInfo *cfile);
> void cifs_oplock_break_put(struct cifsFileInfo *cfile);
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index 0e4e057..7c1ed01 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -53,6 +53,9 @@ do { \
> cFYI(1, "CIFS VFS: leaving %s (xid = %d) rc = %d", \
> __func__, curr_xid, (int)rc); \
> } while (0)
> +extern int init_cifs_idmap(void);
> +extern void exit_cifs_idmap(void);
> +extern void cifs_destroy_idmaptrees(void);
> extern char *build_path_from_dentry(struct dentry *);
> extern char *cifs_build_path_to_root(struct cifs_sb_info *cifs_sb,
> struct cifsTconInfo *tcon);
> --
> 1.6.0.2
>
>
--
Thanks,
Steve
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