diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 87 |
1 files changed, 52 insertions, 35 deletions
diff --git a/fs/namei.c b/fs/namei.c index e499fb609271..f397ab5704e7 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2834,9 +2834,9 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, } EXPORT_SYMBOL(vfs_path_lookup); -static int lookup_one_common(struct mnt_idmap *idmap, - const char *name, struct dentry *base, int len, - struct qstr *this) +static int lookup_noperm_common(const char *name, struct dentry *base, + int len, + struct qstr *this) { this->name = name; this->len = len; @@ -2861,50 +2861,58 @@ static int lookup_one_common(struct mnt_idmap *idmap, if (err < 0) return err; } + return 0; +} +static int lookup_one_common(struct mnt_idmap *idmap, + const char *name, struct dentry *base, int len, + struct qstr *this) { + int err; + err = lookup_noperm_common(name, base, len, this); + if (err < 0) + return err; return inode_permission(idmap, base->d_inode, MAY_EXEC); } /** - * try_lookup_one_len - filesystem helper to lookup single pathname component - * @name: pathname component to lookup + * try_lookup_noperm - filesystem helper to lookup single pathname component + * @name: qstr storing pathname component to lookup * @base: base directory to lookup from - * @len: maximum length @len should be interpreted to * * Look up a dentry by name in the dcache, returning NULL if it does not * currently exist. The function does not try to create a dentry. * * Note that this routine is purely a helper for filesystem usage and should - * not be called by generic code. + * not be called by generic code. It does no permission checking. * * No locks need be held - only a counted reference to @base is needed. * */ -struct dentry *try_lookup_one_len(const char *name, struct dentry *base, int len) +struct dentry *try_lookup_noperm(struct qstr *name, struct dentry *base) { struct qstr this; int err; - err = lookup_one_common(&nop_mnt_idmap, name, base, len, &this); + err = lookup_noperm_common(name->name, base, name->len, &this); if (err) return ERR_PTR(err); - return lookup_dcache(&this, base, 0); + name->hash = this.hash; + return lookup_dcache(name, base, 0); } -EXPORT_SYMBOL(try_lookup_one_len); +EXPORT_SYMBOL(try_lookup_noperm); /** - * lookup_one_len - filesystem helper to lookup single pathname component - * @name: pathname component to lookup + * lookup_noperm - filesystem helper to lookup single pathname component + * @name: qstr storing pathname component to lookup * @base: base directory to lookup from - * @len: maximum length @len should be interpreted to * * Note that this routine is purely a helper for filesystem usage and should - * not be called by generic code. + * not be called by generic code. It does no permission checking. * * The caller must hold base->i_mutex. */ -struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) +struct dentry *lookup_noperm(struct qstr *name, struct dentry *base) { struct dentry *dentry; struct qstr this; @@ -2912,14 +2920,14 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) WARN_ON_ONCE(!inode_is_locked(base->d_inode)); - err = lookup_one_common(&nop_mnt_idmap, name, base, len, &this); + err = lookup_noperm_common(name->name, base, name->len, &this); if (err) return ERR_PTR(err); dentry = lookup_dcache(&this, base, 0); return dentry ? dentry : __lookup_slow(&this, base, 0); } -EXPORT_SYMBOL(lookup_one_len); +EXPORT_SYMBOL(lookup_noperm); /** * lookup_one - lookup single pathname component @@ -2957,7 +2965,7 @@ EXPORT_SYMBOL(lookup_one); * * This can be used for in-kernel filesystem clients such as file servers. * - * Unlike lookup_one_len, it should be called without the parent + * Unlike lookup_one, it should be called without the parent * i_rwsem held, and will take the i_rwsem itself if necessary. */ struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap, @@ -3010,39 +3018,48 @@ struct dentry *lookup_one_positive_unlocked(struct mnt_idmap *idmap, EXPORT_SYMBOL(lookup_one_positive_unlocked); /** - * lookup_one_len_unlocked - filesystem helper to lookup single pathname component + * lookup_noperm_unlocked - filesystem helper to lookup single pathname component * @name: pathname component to lookup * @base: base directory to lookup from - * @len: maximum length @len should be interpreted to * * Note that this routine is purely a helper for filesystem usage and should - * not be called by generic code. + * not be called by generic code. It does no permission checking. * - * Unlike lookup_one_len, it should be called without the parent - * i_mutex held, and will take the i_mutex itself if necessary. + * Unlike lookup_noperm, it should be called without the parent + * i_rwsem held, and will take the i_rwsem itself if necessary. */ -struct dentry *lookup_one_len_unlocked(const char *name, - struct dentry *base, int len) +struct dentry *lookup_noperm_unlocked(struct qstr *name, struct dentry *base) { - return lookup_one_unlocked(&nop_mnt_idmap, &QSTR_LEN(name, len), base); + struct dentry *ret; + + ret = try_lookup_noperm(name, base); + if (!ret) + ret = lookup_slow(name, base, 0); + return ret; } -EXPORT_SYMBOL(lookup_one_len_unlocked); +EXPORT_SYMBOL(lookup_noperm_unlocked); /* - * Like lookup_one_len_unlocked(), except that it yields ERR_PTR(-ENOENT) + * Like lookup_noperm_unlocked(), except that it yields ERR_PTR(-ENOENT) * on negatives. Returns known positive or ERR_PTR(); that's what * most of the users want. Note that pinned negative with unlocked parent - * _can_ become positive at any time, so callers of lookup_one_len_unlocked() + * _can_ become positive at any time, so callers of lookup_noperm_unlocked() * need to be very careful; pinned positives have ->d_inode stable, so * this one avoids such problems. */ -struct dentry *lookup_positive_unlocked(const char *name, - struct dentry *base, int len) +struct dentry *lookup_noperm_positive_unlocked(struct qstr *name, + struct dentry *base) { - return lookup_one_positive_unlocked(&nop_mnt_idmap, - &QSTR_LEN(name, len), base); + struct dentry *ret; + + ret = lookup_noperm_unlocked(name, base); + if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) { + dput(ret); + ret = ERR_PTR(-ENOENT); + } + return ret; } -EXPORT_SYMBOL(lookup_positive_unlocked); +EXPORT_SYMBOL(lookup_noperm_positive_unlocked); #ifdef CONFIG_UNIX98_PTYS int path_pts(struct path *path) |