diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/afs/dir.c | 54 | ||||
| -rw-r--r-- | fs/afs/security.c | 75 |
2 files changed, 112 insertions, 17 deletions
diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 139b4e3cc946..cc12772d0a4d 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -966,6 +966,58 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry, } /* + * Check the validity of a dentry under RCU conditions. + */ +static int afs_d_revalidate_rcu(struct dentry *dentry) +{ + struct afs_vnode *dvnode, *vnode; + struct dentry *parent; + struct inode *dir, *inode; + long dir_version, de_version; + + _enter("%p", dentry); + + /* Check the parent directory is still valid first. */ + parent = READ_ONCE(dentry->d_parent); + dir = d_inode_rcu(parent); + if (!dir) + return -ECHILD; + dvnode = AFS_FS_I(dir); + if (test_bit(AFS_VNODE_DELETED, &dvnode->flags)) + return -ECHILD; + + if (!afs_check_validity(dvnode)) + return -ECHILD; + + /* We only need to invalidate a dentry if the server's copy changed + * behind our back. If we made the change, it's no problem. Note that + * on a 32-bit system, we only have 32 bits in the dentry to store the + * version. + */ + dir_version = (long)READ_ONCE(dvnode->status.data_version); + de_version = (long)READ_ONCE(dentry->d_fsdata); + if (de_version != dir_version) { + dir_version = (long)READ_ONCE(dvnode->invalid_before); + if (de_version - dir_version < 0) + return -ECHILD; + } + + /* Check to see if the vnode referred to by the dentry still + * has a callback. + */ + if (d_really_is_positive(dentry)) { + inode = d_inode_rcu(dentry); + if (inode) { + vnode = AFS_FS_I(inode); + if (!afs_check_validity(vnode)) + return -ECHILD; + } + } + + return 1; /* Still valid */ +} + +/* * check that a dentry lookup hit has found a valid entry * - NOTE! the hit can be a negative hit too, so we can't assume we have an * inode @@ -982,7 +1034,7 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags) int ret; if (flags & LOOKUP_RCU) - return -ECHILD; + return afs_d_revalidate_rcu(dentry); if (d_really_is_positive(dentry)) { vnode = AFS_FS_I(d_inode(dentry)); diff --git a/fs/afs/security.c b/fs/afs/security.c index ef2fd34ba282..ce9de1e6742b 100644 --- a/fs/afs/security.c +++ b/fs/afs/security.c @@ -303,6 +303,40 @@ someone_else_changed_it: return; } +static bool afs_check_permit_rcu(struct afs_vnode *vnode, struct key *key, + afs_access_t *_access) +{ + const struct afs_permits *permits; + int i; + + _enter("{%llx:%llu},%x", + vnode->fid.vid, vnode->fid.vnode, key_serial(key)); + + /* check the permits to see if we've got one yet */ + if (key == vnode->volume->cell->anonymous_key) { + *_access = vnode->status.anon_access; + _leave(" = t [anon %x]", *_access); + return true; + } + + permits = rcu_dereference(vnode->permit_cache); + if (permits) { + for (i = 0; i < permits->nr_permits; i++) { + if (permits->permits[i].key < key) + continue; + if (permits->permits[i].key > key) + break; + + *_access = permits->permits[i].access; + _leave(" = %u [perm %x]", !permits->invalidated, *_access); + return !permits->invalidated; + } + } + + _leave(" = f"); + return false; +} + /* * check with the fileserver to see if the directory or parent directory is * permitted to be accessed with this authorisation, and if so, what access it @@ -369,33 +403,42 @@ int afs_permission(struct inode *inode, int mask) struct afs_vnode *vnode = AFS_FS_I(inode); afs_access_t uninitialized_var(access); struct key *key; - int ret; - - if (mask & MAY_NOT_BLOCK) - return -ECHILD; + int ret = 0; _enter("{{%llx:%llu},%lx},%x,", vnode->fid.vid, vnode->fid.vnode, vnode->flags, mask); - key = afs_request_key(vnode->volume->cell); - if (IS_ERR(key)) { - _leave(" = %ld [key]", PTR_ERR(key)); - return PTR_ERR(key); - } + if (mask & MAY_NOT_BLOCK) { + key = afs_request_key_rcu(vnode->volume->cell); + if (IS_ERR(key)) + return -ECHILD; - ret = afs_validate(vnode, key); - if (ret < 0) - goto error; + ret = -ECHILD; + if (!afs_check_validity(vnode) || + !afs_check_permit_rcu(vnode, key, &access)) + goto error; + } else { + key = afs_request_key(vnode->volume->cell); + if (IS_ERR(key)) { + _leave(" = %ld [key]", PTR_ERR(key)); + return PTR_ERR(key); + } - /* check the permits to see if we've got one yet */ - ret = afs_check_permit(vnode, key, &access); - if (ret < 0) - goto error; + ret = afs_validate(vnode, key); + if (ret < 0) + goto error; + + /* check the permits to see if we've got one yet */ + ret = afs_check_permit(vnode, key, &access); + if (ret < 0) + goto error; + } /* interpret the access mask */ _debug("REQ %x ACC %x on %s", mask, access, S_ISDIR(inode->i_mode) ? "dir" : "file"); + ret = 0; if (S_ISDIR(inode->i_mode)) { if (mask & (MAY_EXEC | MAY_READ | MAY_CHDIR)) { if (!(access & AFS_ACE_LOOKUP)) |