diff options
| -rw-r--r-- | fs/dcache.c | 50 | ||||
| -rw-r--r-- | fs/namei.c | 104 | ||||
| -rw-r--r-- | include/linux/dcache.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/fs.h | 1 | ||||
| -rw-r--r-- | security/security.c | 16 |
5 files changed, 131 insertions, 41 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index ca02c13..66cba5a 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2483,12 +2483,14 @@ static void switch_names(struct dentry *dentry, struct dentry *target) dentry->d_name.name = dentry->d_iname; } else { /* - * Both are internal. Just copy target to dentry + * Both are internal. */ - memcpy(dentry->d_iname, target->d_name.name, - target->d_name.len + 1); - dentry->d_name.len = target->d_name.len; - return; + unsigned int i; + BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long))); + for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) { + swap(((long *) &dentry->d_iname)[i], + ((long *) &target->d_iname)[i]); + } } } swap(dentry->d_name.len, target->d_name.len); @@ -2545,13 +2547,15 @@ static void dentry_unlock_parents_for_move(struct dentry *dentry, * __d_move - move a dentry * @dentry: entry to move * @target: new dentry + * @exchange: exchange the two dentries * * Update the dcache to reflect the move of a file name. Negative * dcache entries should not be moved in this way. Caller must hold * rename_lock, the i_mutex of the source and target directories, * and the sb->s_vfs_rename_mutex if they differ. See lock_rename(). */ -static void __d_move(struct dentry * dentry, struct dentry * target) +static void __d_move(struct dentry *dentry, struct dentry *target, + bool exchange) { if (!dentry->d_inode) printk(KERN_WARNING "VFS: moving negative dcache entry\n"); @@ -2573,8 +2577,15 @@ static void __d_move(struct dentry * dentry, struct dentry * target) __d_drop(dentry); __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash)); - /* Unhash the target: dput() will then get rid of it */ + /* + * Unhash the target (d_delete() is not usable here). If exchanging + * the two dentries, then rehash onto the other's hash queue. + */ __d_drop(target); + if (exchange) { + __d_rehash(target, + d_hash(dentry->d_parent, dentry->d_name.hash)); + } list_del(&dentry->d_u.d_child); list_del(&target->d_u.d_child); @@ -2601,6 +2612,8 @@ static void __d_move(struct dentry * dentry, struct dentry * target) write_seqcount_end(&dentry->d_seq); dentry_unlock_parents_for_move(dentry, target); + if (exchange) + fsnotify_d_move(target); spin_unlock(&target->d_lock); fsnotify_d_move(dentry); spin_unlock(&dentry->d_lock); @@ -2618,11 +2631,30 @@ static void __d_move(struct dentry * dentry, struct dentry * target) void d_move(struct dentry *dentry, struct dentry *target) { write_seqlock(&rename_lock); - __d_move(dentry, target); + __d_move(dentry, target, false); write_sequnlock(&rename_lock); } EXPORT_SYMBOL(d_move); +/* + * d_exchange - exchange two dentries + * @dentry1: first dentry + * @dentry2: second dentry + */ +void d_exchange(struct dentry *dentry1, struct dentry *dentry2) +{ + write_seqlock(&rename_lock); + + WARN_ON(!dentry1->d_inode); + WARN_ON(!dentry2->d_inode); + WARN_ON(IS_ROOT(dentry1)); + WARN_ON(IS_ROOT(dentry2)); + + __d_move(dentry1, dentry2, true); + + write_sequnlock(&rename_lock); +} + /** * d_ancestor - search for an ancestor * @p1: ancestor dentry @@ -2670,7 +2702,7 @@ static struct dentry *__d_unalias(struct inode *inode, m2 = &alias->d_parent->d_inode->i_mutex; out_unalias: if (likely(!d_mountpoint(alias))) { - __d_move(alias, dentry); + __d_move(alias, dentry, false); ret = alias; } out_err: @@ -4031,6 +4031,8 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, const unsigned char *old_name; struct inode *source = old_dentry->d_inode; struct inode *target = new_dentry->d_inode; + bool new_is_dir = false; + unsigned max_links = new_dir->i_sb->s_max_links; if (source == target) return 0; @@ -4039,10 +4041,16 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (error) return error; - if (!target) + if (!target) { error = may_create(new_dir, new_dentry); - else - error = may_delete(new_dir, new_dentry, is_dir); + } else { + new_is_dir = d_is_dir(new_dentry); + + if (!(flags & RENAME_EXCHANGE)) + error = may_delete(new_dir, new_dentry, is_dir); + else + error = may_delete(new_dir, new_dentry, new_is_dir); + } if (error) return error; @@ -4056,10 +4064,17 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, * If we are going to change the parent - check write permissions, * we'll need to flip '..'. */ - if (is_dir && new_dir != old_dir) { - error = inode_permission(source, MAY_WRITE); - if (error) - return error; + if (new_dir != old_dir) { + if (is_dir) { + error = inode_permission(source, MAY_WRITE); + if (error) + return error; + } + if ((flags & RENAME_EXCHANGE) && new_is_dir) { + error = inode_permission(target, MAY_WRITE); + if (error) + return error; + } } error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry, @@ -4069,7 +4084,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, old_name = fsnotify_oldname_init(old_dentry->d_name.name); dget(new_dentry); - if (!is_dir) + if (!is_dir || (flags & RENAME_EXCHANGE)) lock_two_nondirectories(source, target); else if (target) mutex_lock(&target->i_mutex); @@ -4078,25 +4093,25 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry)) goto out; - if (is_dir) { - unsigned max_links = new_dir->i_sb->s_max_links; - + if (max_links && new_dir != old_dir) { error = -EMLINK; - if (max_links && !target && new_dir != old_dir && - new_dir->i_nlink >= max_links) + if (is_dir && !new_is_dir && new_dir->i_nlink >= max_links) goto out; - - if (target) - shrink_dcache_parent(new_dentry); - } else { + if ((flags & RENAME_EXCHANGE) && !is_dir && new_is_dir && + old_dir->i_nlink >= max_links) + goto out; + } + if (is_dir && !(flags & RENAME_EXCHANGE) && target) + shrink_dcache_parent(new_dentry); + if (!is_dir) { error = try_break_deleg(source, delegated_inode); if (error) goto out; - if (target) { - error = try_break_deleg(target, delegated_inode); - if (error) - goto out; - } + } + if (target && !new_is_dir) { + error = try_break_deleg(target, delegated_inode); + if (error) + goto out; } if (!flags) { error = old_dir->i_op->rename(old_dir, old_dentry, @@ -4108,22 +4123,31 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (error) goto out; - if (target) { + if (!(flags & RENAME_EXCHANGE) && target) { if (is_dir) target->i_flags |= S_DEAD; dont_mount(new_dentry); } - if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) - d_move(old_dentry, new_dentry); + if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) { + if (!(flags & RENAME_EXCHANGE)) + d_move(old_dentry, new_dentry); + else + d_exchange(old_dentry, new_dentry); + } out: - if (!is_dir) + if (!is_dir || (flags & RENAME_EXCHANGE)) unlock_two_nondirectories(source, target); else if (target) mutex_unlock(&target->i_mutex); dput(new_dentry); - if (!error) + if (!error) { fsnotify_move(old_dir, new_dir, old_name, is_dir, - target, old_dentry); + !(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry); + if (flags & RENAME_EXCHANGE) { + fsnotify_move(new_dir, old_dir, old_dentry->d_name.name, + new_is_dir, NULL, new_dentry); + } + } fsnotify_oldname_free(old_name); return error; @@ -4143,7 +4167,10 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, bool should_retry = false; int error; - if (flags & ~RENAME_NOREPLACE) + if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) + return -EINVAL; + + if ((flags & RENAME_NOREPLACE) && (flags & RENAME_EXCHANGE)) return -EINVAL; retry: @@ -4180,7 +4207,8 @@ retry: oldnd.flags &= ~LOOKUP_PARENT; newnd.flags &= ~LOOKUP_PARENT; - newnd.flags |= LOOKUP_RENAME_TARGET; + if (!(flags & RENAME_EXCHANGE)) + newnd.flags |= LOOKUP_RENAME_TARGET; retry_deleg: trap = lock_rename(new_dir, old_dir); @@ -4200,12 +4228,23 @@ retry_deleg: error = -EEXIST; if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry)) goto exit5; + if (flags & RENAME_EXCHANGE) { + error = -ENOENT; + if (d_is_negative(new_dentry)) + goto exit5; + + if (!d_is_dir(new_dentry)) { + error = -ENOTDIR; + if (newnd.last.name[newnd.last.len]) + goto exit5; + } + } /* unless the source is a directory trailing slashes give -ENOTDIR */ if (!d_is_dir(old_dentry)) { error = -ENOTDIR; if (oldnd.last.name[oldnd.last.len]) goto exit5; - if (newnd.last.name[newnd.last.len]) + if (!(flags & RENAME_EXCHANGE) && newnd.last.name[newnd.last.len]) goto exit5; } /* source should not be ancestor of target */ @@ -4213,7 +4252,8 @@ retry_deleg: if (old_dentry == trap) goto exit5; /* target should not be an ancestor of source */ - error = -ENOTEMPTY; + if (!(flags & RENAME_EXCHANGE)) + error = -ENOTEMPTY; if (new_dentry == trap) goto exit5; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 3b50cac..3b9bfdb 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -308,6 +308,7 @@ extern void dentry_update_name_case(struct dentry *, struct qstr *); /* used for rename() and baskets */ extern void d_move(struct dentry *, struct dentry *); +extern void d_exchange(struct dentry *, struct dentry *); extern struct dentry *d_ancestor(struct dentry *, struct dentry *); /* appendix may either be NULL or be used for transname suffixes */ diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 9250f4d..ca1a11b 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -36,6 +36,7 @@ #define SEEK_MAX SEEK_HOLE #define RENAME_NOREPLACE (1 << 0) /* Don't overwrite target */ +#define RENAME_EXCHANGE (1 << 1) /* Exchange source and dest */ struct fstrim_range { __u64 start; diff --git a/security/security.c b/security/security.c index 284fbc9..8b774f3 100644 --- a/security/security.c +++ b/security/security.c @@ -439,6 +439,14 @@ int security_path_rename(struct path *old_dir, struct dentry *old_dentry, if (unlikely(IS_PRIVATE(old_dentry->d_inode) || (new_dentry->d_inode && IS_PRIVATE(new_dentry->d_inode)))) return 0; + + if (flags & RENAME_EXCHANGE) { + int err = security_ops->path_rename(new_dir, new_dentry, + old_dir, old_dentry); + if (err) + return err; + } + return security_ops->path_rename(old_dir, old_dentry, new_dir, new_dentry); } @@ -531,6 +539,14 @@ int security_inode_rename(struct inode *old_dir, struct dentry *old_dentry, if (unlikely(IS_PRIVATE(old_dentry->d_inode) || (new_dentry->d_inode && IS_PRIVATE(new_dentry->d_inode)))) return 0; + + if (flags & RENAME_EXCHANGE) { + int err = security_ops->inode_rename(new_dir, new_dentry, + old_dir, old_dentry); + if (err) + return err; + } + return security_ops->inode_rename(old_dir, old_dentry, new_dir, new_dentry); } |
