On Tue, Apr 26, 2011 at 8:44 PM, Steve French <smfrench@xxxxxxxxx> wrote:
> 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
>
In which case, I think perhaps invocation of these three functions in cifsfs.c
should be moved under config option CONFIG_CIFS_ACL instead of
CONFIG_CIFS_UPCALL
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