#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
+#include <linux/sched/mm.h>
#include <linux/fsnotify.h>
#include <linux/personality.h>
#include <linux/security.h>
static bool legitimize_root(struct nameidata *nd)
{
- /*
- * For scoped-lookups (where nd->root has been zeroed), we need to
- * restart the whole lookup from scratch -- because set_root() is wrong
- * for these lookups (nd->dfd is the root, not the filesystem root).
- */
- if (!nd->root.mnt && (nd->flags & LOOKUP_IS_SCOPED))
- return false;
/* Nothing to do if nd->root is zero or is managed by the VFS user. */
if (!nd->root.mnt || (nd->state & ND_ROOT_PRESET))
return true;
* @seq: seq number to check @dentry against
* Returns: true on success, false on failure
*
- * Similar to to try_to_unlazy(), but here we have the next dentry already
+ * Similar to try_to_unlazy(), but here we have the next dentry already
* picked by rcu-walk and want to legitimize that in addition to the current
* nd->path and nd->root for ref-walk mode. Must be called from rcu-walk context.
* Nothing should touch nameidata between try_to_unlazy_next() failure and
.procname = "protected_symlinks",
.data = &sysctl_protected_symlinks,
.maxlen = sizeof(int),
- .mode = 0600,
+ .mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
.procname = "protected_hardlinks",
.data = &sysctl_protected_hardlinks,
.maxlen = sizeof(int),
- .mode = 0600,
+ .mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
.procname = "protected_fifos",
.data = &sysctl_protected_fifos,
.maxlen = sizeof(int),
- .mode = 0600,
+ .mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,
.procname = "protected_regular",
.data = &sysctl_protected_regular,
.maxlen = sizeof(int),
- .mode = 0600,
+ .mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,
// unlazy even if we fail to grab the link - cleanup needs it
bool grabbed_link = legitimize_path(nd, link, seq);
- if (!try_to_unlazy(nd) != 0 || !grabbed_link)
+ if (!try_to_unlazy(nd) || !grabbed_link)
return -ECHILD;
if (nd_alloc_stack(nd))
EXPORT_SYMBOL(lookup_one);
/**
- * lookup_one_len_unlocked - filesystem helper to lookup single pathname component
+ * lookup_one_unlocked - filesystem helper to lookup single pathname component
+ * @mnt_userns: idmapping of the mount the lookup is performed from
* @name: pathname component to lookup
* @base: base directory to lookup from
* @len: maximum length @len should be interpreted to
* Unlike lookup_one_len, it should be called without the parent
* i_mutex held, and will take the i_mutex itself if necessary.
*/
-struct dentry *lookup_one_len_unlocked(const char *name,
- struct dentry *base, int len)
+struct dentry *lookup_one_unlocked(struct user_namespace *mnt_userns,
+ const char *name, struct dentry *base,
+ int len)
{
struct qstr this;
int err;
struct dentry *ret;
- err = lookup_one_common(&init_user_ns, name, base, len, &this);
+ err = lookup_one_common(mnt_userns, name, base, len, &this);
if (err)
return ERR_PTR(err);
ret = lookup_slow(&this, base, 0);
return ret;
}
+EXPORT_SYMBOL(lookup_one_unlocked);
+
+/**
+ * lookup_one_positive_unlocked - filesystem helper to lookup single
+ * pathname component
+ * @mnt_userns: idmapping of the mount the lookup is performed from
+ * @name: pathname component to lookup
+ * @base: base directory to lookup from
+ * @len: maximum length @len should be interpreted to
+ *
+ * This helper will yield ERR_PTR(-ENOENT) on negatives. The helper returns
+ * known positive or ERR_PTR(). This is what most of the users want.
+ *
+ * Note that pinned negative with unlocked parent _can_ become positive at any
+ * time, so callers of lookup_one_unlocked() need to be very careful; pinned
+ * positives have >d_inode stable, so this one avoids such problems.
+ *
+ * Note that this routine is purely a helper for filesystem usage and should
+ * not be called by generic code.
+ *
+ * The helper should be called without i_mutex held.
+ */
+struct dentry *lookup_one_positive_unlocked(struct user_namespace *mnt_userns,
+ const char *name,
+ struct dentry *base, int len)
+{
+ struct dentry *ret = lookup_one_unlocked(mnt_userns, name, base, len);
+
+ if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
+ dput(ret);
+ ret = ERR_PTR(-ENOENT);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(lookup_one_positive_unlocked);
+
+/**
+ * lookup_one_len_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.
+ *
+ * Unlike lookup_one_len, it should be called without the parent
+ * i_mutex held, and will take the i_mutex itself if necessary.
+ */
+struct dentry *lookup_one_len_unlocked(const char *name,
+ struct dentry *base, int len)
+{
+ return lookup_one_unlocked(&init_user_ns, name, base, len);
+}
EXPORT_SYMBOL(lookup_one_len_unlocked);
/*
struct dentry *lookup_positive_unlocked(const char *name,
struct dentry *base, int len)
{
- struct dentry *ret = lookup_one_len_unlocked(name, base, len);
- if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
- dput(ret);
- ret = ERR_PTR(-ENOENT);
- }
- return ret;
+ return lookup_one_positive_unlocked(&init_user_ns, name, base, len);
}
EXPORT_SYMBOL(lookup_positive_unlocked);
{
struct dentry *dentry = ERR_PTR(-EEXIST);
struct qstr last;
+ bool want_dir = lookup_flags & LOOKUP_DIRECTORY;
+ unsigned int reval_flag = lookup_flags & LOOKUP_REVAL;
+ unsigned int create_flags = LOOKUP_CREATE | LOOKUP_EXCL;
int type;
int err2;
int error;
- bool is_dir = (lookup_flags & LOOKUP_DIRECTORY);
-
- /*
- * Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any
- * other flags passed in are ignored!
- */
- lookup_flags &= LOOKUP_REVAL;
- error = filename_parentat(dfd, name, lookup_flags, path, &last, &type);
+ error = filename_parentat(dfd, name, reval_flag, path, &last, &type);
if (error)
return ERR_PTR(error);
/* don't fail immediately if it's r/o, at least try to report other errors */
err2 = mnt_want_write(path->mnt);
/*
- * Do the final lookup.
+ * Do the final lookup. Suppress 'create' if there is a trailing
+ * '/', and a directory wasn't requested.
*/
- lookup_flags |= LOOKUP_CREATE | LOOKUP_EXCL;
+ if (last.name[last.len] && !want_dir)
+ create_flags = 0;
inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
- dentry = __lookup_hash(&last, path->dentry, lookup_flags);
+ dentry = __lookup_hash(&last, path->dentry, reval_flag | create_flags);
if (IS_ERR(dentry))
goto unlock;
* all is fine. Let's be bastards - you had / on the end, you've
* been asking for (non-existent) directory. -ENOENT for you.
*/
- if (unlikely(!is_dir && last.name[last.len])) {
+ if (unlikely(!create_flags)) {
error = -ENOENT;
goto fail;
}
}
EXPORT_SYMBOL(page_readlink);
-/*
- * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS
- */
-int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)
+int page_symlink(struct inode *inode, const char *symname, int len)
{
struct address_space *mapping = inode->i_mapping;
+ const struct address_space_operations *aops = mapping->a_ops;
+ bool nofs = !mapping_gfp_constraint(mapping, __GFP_FS);
struct page *page;
void *fsdata;
int err;
- unsigned int flags = 0;
- if (nofs)
- flags |= AOP_FLAG_NOFS;
+ unsigned int flags;
retry:
- err = pagecache_write_begin(NULL, mapping, 0, len-1,
- flags, &page, &fsdata);
+ if (nofs)
+ flags = memalloc_nofs_save();
+ err = aops->write_begin(NULL, mapping, 0, len-1, &page, &fsdata);
+ if (nofs)
+ memalloc_nofs_restore(flags);
if (err)
goto fail;
memcpy(page_address(page), symname, len-1);
- err = pagecache_write_end(NULL, mapping, 0, len-1, len-1,
+ err = aops->write_end(NULL, mapping, 0, len-1, len-1,
page, fsdata);
if (err < 0)
goto fail;
fail:
return err;
}
-EXPORT_SYMBOL(__page_symlink);
-
-int page_symlink(struct inode *inode, const char *symname, int len)
-{
- return __page_symlink(inode, symname, len,
- !mapping_gfp_constraint(inode->i_mapping, __GFP_FS));
-}
EXPORT_SYMBOL(page_symlink);
const struct inode_operations page_symlink_inode_operations = {
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