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Diffstat (limited to 'fs')
-rw-r--r--fs/namei.c521
1 files changed, 262 insertions, 259 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 0741c69b331..9a6456099f1 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -498,8 +498,6 @@ static int link_path_walk(const char *, struct nameidata *);
static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link)
{
- int res = 0;
- char *name;
if (IS_ERR(link))
goto fail;
@@ -510,22 +508,7 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l
path_get(&nd->root);
}
- res = link_path_walk(link, nd);
- if (nd->depth || res || nd->last_type!=LAST_NORM)
- return res;
- /*
- * If it is an iterative symlinks resolution in open_namei() we
- * have to copy the last component. And all that crap because of
- * bloody create() on broken symlinks. Furrfu...
- */
- name = __getname();
- if (unlikely(!name)) {
- path_put(&nd->path);
- return -ENOMEM;
- }
- strcpy(name, nd->last.name);
- nd->last.name = name;
- return 0;
+ return link_path_walk(link, nd);
fail:
path_put(&nd->path);
return PTR_ERR(link);
@@ -547,10 +530,10 @@ static inline void path_to_nameidata(struct path *path, struct nameidata *nd)
nd->path.dentry = path->dentry;
}
-static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd)
+static __always_inline int
+__do_follow_link(struct path *path, struct nameidata *nd, void **p)
{
int error;
- void *cookie;
struct dentry *dentry = path->dentry;
touch_atime(path->mnt, dentry);
@@ -562,9 +545,9 @@ static __always_inline int __do_follow_link(struct path *path, struct nameidata
}
mntget(path->mnt);
nd->last_type = LAST_BIND;
- cookie = dentry->d_inode->i_op->follow_link(dentry, nd);
- error = PTR_ERR(cookie);
- if (!IS_ERR(cookie)) {
+ *p = dentry->d_inode->i_op->follow_link(dentry, nd);
+ error = PTR_ERR(*p);
+ if (!IS_ERR(*p)) {
char *s = nd_get_link(nd);
error = 0;
if (s)
@@ -574,8 +557,6 @@ static __always_inline int __do_follow_link(struct path *path, struct nameidata
if (error)
path_put(&nd->path);
}
- if (dentry->d_inode->i_op->put_link)
- dentry->d_inode->i_op->put_link(dentry, nd, cookie);
}
return error;
}
@@ -589,6 +570,7 @@ static __always_inline int __do_follow_link(struct path *path, struct nameidata
*/
static inline int do_follow_link(struct path *path, struct nameidata *nd)
{
+ void *cookie;
int err = -ELOOP;
if (current->link_count >= MAX_NESTED_LINKS)
goto loop;
@@ -602,7 +584,9 @@ static inline int do_follow_link(struct path *path, struct nameidata *nd)
current->link_count++;
current->total_link_count++;
nd->depth++;
- err = __do_follow_link(path, nd);
+ err = __do_follow_link(path, nd, &cookie);
+ if (!IS_ERR(cookie) && path->dentry->d_inode->i_op->put_link)
+ path->dentry->d_inode->i_op->put_link(path->dentry, nd, cookie);
path_put(path);
current->link_count--;
nd->depth--;
@@ -1375,22 +1359,6 @@ static inline int may_create(struct inode *dir, struct dentry *child)
return inode_permission(dir, MAY_WRITE | MAY_EXEC);
}
-/*
- * O_DIRECTORY translates into forcing a directory lookup.
- */
-static inline int lookup_flags(unsigned int f)
-{
- unsigned long retval = LOOKUP_FOLLOW;
-
- if (f & O_NOFOLLOW)
- retval &= ~LOOKUP_FOLLOW;
-
- if (f & O_DIRECTORY)
- retval |= LOOKUP_DIRECTORY;
-
- return retval;
-}
-
/*
* p1 and p2 should be directories on the same fs.
*/
@@ -1590,129 +1558,135 @@ static int open_will_truncate(int flag, struct inode *inode)
return (flag & O_TRUNC);
}
-/*
- * Note that the low bits of the passed in "open_flag"
- * are not the same as in the local variable "flag". See
- * open_to_namei_flags() for more details.
- */
-struct file *do_filp_open(int dfd, const char *pathname,
- int open_flag, int mode, int acc_mode)
+static struct file *finish_open(struct nameidata *nd,
+ int open_flag, int acc_mode)
{
struct file *filp;
- struct nameidata nd;
- int error;
- struct path path;
- struct dentry *dir;
- int count = 0;
int will_truncate;
- int flag = open_to_namei_flags(open_flag);
- int force_reval = 0;
+ int error;
+ will_truncate = open_will_truncate(open_flag, nd->path.dentry->d_inode);
+ if (will_truncate) {
+ error = mnt_want_write(nd->path.mnt);
+ if (error)
+ goto exit;
+ }
+ error = may_open(&nd->path, acc_mode, open_flag);
+ if (error) {
+ if (will_truncate)
+ mnt_drop_write(nd->path.mnt);
+ goto exit;
+ }
+ filp = nameidata_to_filp(nd);
+ if (!IS_ERR(filp)) {
+ error = ima_file_check(filp, acc_mode);
+ if (error) {
+ fput(filp);
+ filp = ERR_PTR(error);
+ }
+ }
+ if (!IS_ERR(filp)) {
+ if (acc_mode & MAY_WRITE)
+ vfs_dq_init(nd->path.dentry->d_inode);
+
+ if (will_truncate) {
+ error = handle_truncate(&nd->path);
+ if (error) {
+ fput(filp);
+ filp = ERR_PTR(error);
+ }
+ }
+ }
/*
- * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
- * check for O_DSYNC if the need any syncing at all we enforce it's
- * always set instead of having to deal with possibly weird behaviour
- * for malicious applications setting only __O_SYNC.
+ * It is now safe to drop the mnt write
+ * because the filp has had a write taken
+ * on its behalf.
*/
- if (open_flag & __O_SYNC)
- open_flag |= O_DSYNC;
-
- if (!acc_mode)
- acc_mode = MAY_OPEN | ACC_MODE(open_flag);
+ if (will_truncate)
+ mnt_drop_write(nd->path.mnt);
+ return filp;
- /* O_TRUNC implies we need access checks for write permissions */
- if (flag & O_TRUNC)
- acc_mode |= MAY_WRITE;
+exit:
+ if (!IS_ERR(nd->intent.open.file))
+ release_open_intent(nd);
+ path_put(&nd->path);
+ return ERR_PTR(error);
+}
- /* Allow the LSM permission hook to distinguish append
- access from general write access. */
- if (flag & O_APPEND)
- acc_mode |= MAY_APPEND;
+static struct file *do_last(struct nameidata *nd, struct path *path,
+ int open_flag, int acc_mode,
+ int mode, const char *pathname,
+ int *want_dir)
+{
+ struct dentry *dir = nd->path.dentry;
+ struct file *filp;
+ int error = -EISDIR;
- /*
- * The simplest case - just a plain lookup.
- */
- if (!(flag & O_CREAT)) {
- filp = get_empty_filp();
-
- if (filp == NULL)
- return ERR_PTR(-ENFILE);
- nd.intent.open.file = filp;
- filp->f_flags = open_flag;
- nd.intent.open.flags = flag;
- nd.intent.open.create_mode = 0;
- error = do_path_lookup(dfd, pathname,
- lookup_flags(flag)|LOOKUP_OPEN, &nd);
- if (IS_ERR(nd.intent.open.file)) {
- if (error == 0) {
- error = PTR_ERR(nd.intent.open.file);
- path_put(&nd.path);
+ switch (nd->last_type) {
+ case LAST_DOTDOT:
+ follow_dotdot(nd);
+ dir = nd->path.dentry;
+ if (nd->path.mnt->mnt_sb->s_type->fs_flags & FS_REVAL_DOT) {
+ if (!dir->d_op->d_revalidate(dir, nd)) {
+ error = -ESTALE;
+ goto exit;
}
- } else if (error)
- release_open_intent(&nd);
- if (error)
- return ERR_PTR(error);
+ }
+ /* fallthrough */
+ case LAST_DOT:
+ case LAST_ROOT:
+ if (open_flag & O_CREAT)
+ goto exit;
+ /* fallthrough */
+ case LAST_BIND:
+ audit_inode(pathname, dir);
goto ok;
}
- /*
- * Create - we need to know the parent.
- */
-reval:
- error = path_init(dfd, pathname, LOOKUP_PARENT, &nd);
- if (error)
- return ERR_PTR(error);
- if (force_reval)
- nd.flags |= LOOKUP_REVAL;
- error = path_walk(pathname, &nd);
- if (error) {
- if (nd.root.mnt)
- path_put(&nd.root);
- return ERR_PTR(error);
+ /* trailing slashes? */
+ if (nd->last.name[nd->last.len]) {
+ if (open_flag & O_CREAT)
+ goto exit;
+ *want_dir = 1;
}
- if (unlikely(!audit_dummy_context()))
- audit_inode(pathname, nd.path.dentry);
- /*
- * We have the parent and last component. First of all, check
- * that we are not asked to creat(2) an obvious directory - that
- * will not do.
- */
- error = -EISDIR;
- if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len])
- goto exit_parent;
+ /* just plain open? */
+ if (!(open_flag & O_CREAT)) {
+ error = do_lookup(nd, &nd->last, path);
+ if (error)
+ goto exit;
+ error = -ENOENT;
+ if (!path->dentry->d_inode)
+ goto exit_dput;
+ if (path->dentry->d_inode->i_op->follow_link)
+ return NULL;
+ error = -ENOTDIR;
+ if (*want_dir & !path->dentry->d_inode->i_op->lookup)
+ goto exit_dput;
+ path_to_nameidata(path, nd);
+ audit_inode(pathname, nd->path.dentry);
+ goto ok;
+ }
- error = -ENFILE;
- filp = get_empty_filp();
- if (filp == NULL)
- goto exit_parent;
- nd.intent.open.file = filp;
- filp->f_flags = open_flag;
- nd.intent.open.flags = flag;
- nd.intent.open.create_mode = mode;
- dir = nd.path.dentry;
- nd.flags &= ~LOOKUP_PARENT;
- nd.flags |= LOOKUP_CREATE | LOOKUP_OPEN;
- if (flag & O_EXCL)
- nd.flags |= LOOKUP_EXCL;
+ /* OK, it's O_CREAT */
mutex_lock(&dir->d_inode->i_mutex);
- path.dentry = lookup_hash(&nd);
- path.mnt = nd.path.mnt;
-do_last:
- error = PTR_ERR(path.dentry);
- if (IS_ERR(path.dentry)) {
+ path->dentry = lookup_hash(nd);
+ path->mnt = nd->path.mnt;
+
+ error = PTR_ERR(path->dentry);
+ if (IS_ERR(path->dentry)) {
mutex_unlock(&dir->d_inode->i_mutex);
goto exit;
}
- if (IS_ERR(nd.intent.open.file)) {
- error = PTR_ERR(nd.intent.open.file);
+ if (IS_ERR(nd->intent.open.file)) {
+ error = PTR_ERR(nd->intent.open.file);
goto exit_mutex_unlock;
}
/* Negative dentry, just create the file */
- if (!path.dentry->d_inode) {
+ if (!path->dentry->d_inode) {
/*
* This write is needed to ensure that a
* ro->rw transition does not occur between
@@ -1720,18 +1694,16 @@ do_last:
* a permanent write count is taken through
* the 'struct file' in nameidata_to_filp().
*/
- error = mnt_want_write(nd.path.mnt);
+ error = mnt_want_write(nd->path.mnt);
if (error)
goto exit_mutex_unlock;
- error = __open_namei_create(&nd, &path, open_flag, mode);
+ error = __open_namei_create(nd, path, open_flag, mode);
if (error) {
- mnt_drop_write(nd.path.mnt);
+ mnt_drop_write(nd->path.mnt);
goto exit;
}
- filp = nameidata_to_filp(&nd);
- mnt_drop_write(nd.path.mnt);
- if (nd.root.mnt)
- path_put(&nd.root);
+ filp = nameidata_to_filp(nd);
+ mnt_drop_write(nd->path.mnt);
if (!IS_ERR(filp)) {
error = ima_file_check(filp, acc_mode);
if (error) {
@@ -1746,150 +1718,181 @@ do_last:
* It already exists.
*/
mutex_unlock(&dir->d_inode->i_mutex);
- audit_inode(pathname, path.dentry);
+ audit_inode(pathname, path->dentry);
error = -EEXIST;
- if (flag & O_EXCL)
+ if (open_flag & O_EXCL)
goto exit_dput;
- if (__follow_mount(&path)) {
+ if (__follow_mount(path)) {
error = -ELOOP;
- if (flag & O_NOFOLLOW)
+ if (open_flag & O_NOFOLLOW)
goto exit_dput;
}
error = -ENOENT;
- if (!path.dentry->d_inode)
+ if (!path->dentry->d_inode)
goto exit_dput;
- if (path.dentry->d_inode->i_op->follow_link)
- goto do_link;
- path_to_nameidata(&path, &nd);
+ if (path->dentry->d_inode->i_op->follow_link)
+ return NULL;
+
+ path_to_nameidata(path, nd);
error = -EISDIR;
- if (S_ISDIR(path.dentry->d_inode->i_mode))
+ if (S_ISDIR(path->dentry->d_inode->i_mode))
goto exit;
ok:
+ filp = finish_open(nd, open_flag, acc_mode);
+ return filp;
+
+exit_mutex_unlock:
+ mutex_unlock(&dir->d_inode->i_mutex);
+exit_dput:
+ path_put_conditional(path, nd);
+exit:
+ if (!IS_ERR(nd->intent.open.file))
+ release_open_intent(nd);
+ path_put(&nd->path);
+ return ERR_PTR(error);
+}
+
+/*
+ * Note that the low bits of the passed in "open_flag"
+ * are not the same as in the local variable "flag". See
+ * open_to_namei_flags() for more details.
+ */
+struct file *do_filp_open(int dfd, const char *pathname,
+ int open_flag, int mode, int acc_mode)
+{
+ struct file *filp;
+ struct nameidata nd;
+ int error;
+ struct path path;
+ int count = 0;
+ int flag = open_to_namei_flags(open_flag);
+ int force_reval = 0;
+ int want_dir = open_flag & O_DIRECTORY;
+
+ if (!(open_flag & O_CREAT))
+ mode = 0;
+
/*
- * Consider:
- * 1. may_open() truncates a file
- * 2. a rw->ro mount transition occurs
- * 3. nameidata_to_filp() fails due to
- * the ro mount.
- * That would be inconsistent, and should
- * be avoided. Taking this mnt write here
- * ensures that (2) can not occur.
+ * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
+ * check for O_DSYNC if the need any syncing at all we enforce it's
+ * always set instead of having to deal with possibly weird behaviour
+ * for malicious applications setting only __O_SYNC.
*/
- will_truncate = open_will_truncate(flag, nd.path.dentry->d_inode);
- if (will_truncate) {
- error = mnt_want_write(nd.path.mnt);
- if (error)
- goto exit;
- }
- error = may_open(&nd.path, acc_mode, open_flag);
+ if (open_flag & __O_SYNC)
+ open_flag |= O_DSYNC;
+
+ if (!acc_mode)
+ acc_mode = MAY_OPEN | ACC_MODE(open_flag);
+
+ /* O_TRUNC implies we need access checks for write permissions */
+ if (open_flag & O_TRUNC)
+ acc_mode |= MAY_WRITE;
+
+ /* Allow the LSM permission hook to distinguish append
+ access from general write access. */
+ if (open_flag & O_APPEND)
+ acc_mode |= MAY_APPEND;
+
+ /* find the parent */
+reval:
+ error = path_init(dfd, pathname, LOOKUP_PARENT, &nd);
+ if (error)
+ return ERR_PTR(error);
+ if (force_reval)
+ nd.flags |= LOOKUP_REVAL;
+
+ current->total_link_count = 0;
+ error = link_path_walk(pathname, &nd);
if (error) {
- if (will_truncate)
- mnt_drop_write(nd.path.mnt);
- goto exit;
- }
- filp = nameidata_to_filp(&nd);
- if (!IS_ERR(filp)) {
- error = ima_file_check(filp, acc_mode);
- if (error) {
- fput(filp);
- filp = ERR_PTR(error);
- }
+ filp = ERR_PTR(error);
+ goto out;
}
- if (!IS_ERR(filp)) {
- if (acc_mode & MAY_WRITE)
- vfs_dq_init(nd.path.dentry->d_inode);
+ if (unlikely(!audit_dummy_context()) && (open_flag & O_CREAT))
+ audit_inode(pathname, nd.path.dentry);
- if (will_truncate) {
- error = handle_truncate(&nd.path);
- if (error) {
- fput(filp);
- filp = ERR_PTR(error);
- }
- }
- }
/*
- * It is now safe to drop the mnt write
- * because the filp has had a write taken
- * on its behalf.
+ * We have the parent and last component.
*/
- if (will_truncate)
- mnt_drop_write(nd.path.mnt);
+
+ error = -ENFILE;
+ filp = get_empty_filp();
+ if (filp == NULL)
+ goto exit_parent;
+ nd.intent.open.file = filp;
+ filp->f_flags = open_flag;
+ nd.intent.open.flags = flag;
+ nd.intent.open.create_mode = mode;
+ nd.flags &= ~LOOKUP_PARENT;
+ nd.flags |= LOOKUP_OPEN;
+ if (open_flag & O_CREAT) {
+ nd.flags |= LOOKUP_CREATE;
+ if (open_flag & O_EXCL)
+ nd.flags |= LOOKUP_EXCL;
+ }
+ filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname, &want_dir);
+ while (unlikely(!filp)) { /* trailing symlink */
+ struct path holder;
+ struct inode *inode = path.dentry->d_inode;
+ void *cookie;
+ error = -ELOOP;
+ /* S_ISDIR part is a temporary automount kludge */
+ if ((open_flag & O_NOFOLLOW) && !S_ISDIR(inode->i_mode))
+ goto exit_dput;
+ if (count++ == 32)
+ goto exit_dput;
+ /*
+ * This is subtle. Instead of calling do_follow_link() we do
+ * the thing by hands. The reason is that this way we have zero
+ * link_count and path_walk() (called from ->follow_link)
+ * honoring LOOKUP_PARENT. After that we have the parent and
+ * last component, i.e. we are in the same situation as after
+ * the first path_walk(). Well, almost - if the last component
+ * is normal we get its copy stored in nd->last.name and we will
+ * have to putname() it when we are done. Procfs-like symlinks
+ * just set LAST_BIND.
+ */
+ nd.flags |= LOOKUP_PARENT;
+ error = security_inode_follow_link(path.dentry, &nd);
+ if (error)
+ goto exit_dput;
+ error = __do_follow_link(&path, &nd, &cookie);
+ if (unlikely(error)) {
+ /* nd.path had been dropped */
+ if (!IS_ERR(cookie) && inode->i_op->put_link)
+ inode->i_op->put_link(path.dentry, &nd, cookie);
+ path_put(&path);
+ release_open_intent(&nd);
+ filp = ERR_PTR(error);
+ goto out;
+ }
+ holder = path;
+ nd.flags &= ~LOOKUP_PARENT;
+ filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname, &want_dir);
+ if (inode->i_op->put_link)
+ inode->i_op->put_link(holder.dentry, &nd, cookie);
+ path_put(&holder);
+ }
+out:
if (nd.root.mnt)
path_put(&nd.root);
+ if (filp == ERR_PTR(-ESTALE) && !force_reval) {
+ force_reval = 1;
+ goto reval;
+ }
return filp;
-exit_mutex_unlock:
- mutex_unlock(&dir->d_inode->i_mutex);
exit_dput:
path_put_conditional(&path, &nd);
-exit:
if (!IS_ERR(nd.intent.open.file))
release_open_intent(&nd);
exit_parent:
- if (nd.root.mnt)
- path_put(&nd.root);
path_put(&nd.path);
- return ERR_PTR(error);
-
-do_link:
- error = -ELOOP;
- if (flag & O_NOFOLLOW)
- goto exit_dput;
- /*
- * This is subtle. Instead of calling do_follow_link() we do the
- * thing by hands. The reason is that this way we have zero link_count
- * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT.
- * After that we have the parent and last component, i.e.
- * we are in the same situation as after the first path_walk().
- * Well, almost - if the last component is normal we get its copy
- * stored in nd->last.name and we will have to putname() it when we
- * are done. Procfs-like symlinks just set LAST_BIND.
- */
- nd.flags |= LOOKUP_PARENT;
- error = security_inode_follow_link(path.dentry, &nd);
- if (error)
- goto exit_dput;
- error = __do_follow_link(&path, &nd);
- path_put(&path);
- if (error) {
- /* Does someone understand code flow here? Or it is only
- * me so stupid? Anathema to whoever designed this non-sense
- * with "intent.open".
- */
- release_open_intent(&nd);
- if (nd.root.mnt)
- path_put(&nd.root);
- if (error == -ESTALE && !force_reval) {
- force_reval = 1;
- goto reval;
- }
- return ERR_PTR(error);
- }
- nd.flags &= ~LOOKUP_PARENT;
- if (nd.last_type == LAST_BIND)
- goto ok;
- error = -EISDIR;
- if (nd.last_type != LAST_NORM)
- goto exit;
- if (nd.last.name[nd.last.len]) {
- __putname(nd.last.name);
- goto exit;
- }
- error = -ELOOP;
- if (count++==32) {
- __putname(nd.last.name);
- goto exit;
- }
- dir = nd.path.dentry;
- mutex_lock(&dir->d_inode->i_mutex);
- path.dentry = lookup_hash(&nd);
- path.mnt = nd.path.mnt;
- __putname(nd.last.name);
- goto do_last;
+ filp = ERR_PTR(error);
+ goto out;
}
/**
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-17 00:35:26 +0000