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make path_init() unconditionally paired with terminate_walk() 

including the failure exits

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2018-07-09 16:27:23 -04:00
parent 5014c2f378
commit edc2b1da77
1 changed files with 16 additions and 16 deletions
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32
fs/namei.c
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@ -2125,12 +2125,15 @@ static int link_path_walk(const char *name, struct nameidata *nd)
}
}
/* must be paired with terminate_walk() */
static const char *path_init(struct nameidata *nd, unsigned flags)
{
const char *s = nd->name->name;
if (!*s)
flags &= ~LOOKUP_RCU;
if (flags & LOOKUP_RCU)
rcu_read_lock();
nd->last_type = LAST_ROOT; /* if there are only slashes... */
nd->flags = flags | LOOKUP_JUMPED | LOOKUP_PARENT;
@ -2143,7 +2146,6 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
nd->path = nd->root;
nd->inode = inode;
if (flags & LOOKUP_RCU) {
rcu_read_lock();
nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
nd->root_seq = nd->seq;
nd->m_seq = read_seqbegin(&mount_lock);
@ -2159,21 +2161,15 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
nd->m_seq = read_seqbegin(&mount_lock);
if (*s == '/') {
if (flags & LOOKUP_RCU)
rcu_read_lock();
set_root(nd);
if (likely(!nd_jump_root(nd)))
return s;
nd->root.mnt = NULL;
rcu_read_unlock();
return ERR_PTR(-ECHILD);
} else if (nd->dfd == AT_FDCWD) {
if (flags & LOOKUP_RCU) {
struct fs_struct *fs = current->fs;
unsigned seq;
rcu_read_lock();
do {
seq = read_seqcount_begin(&fs->seq);
nd->path = fs->pwd;
@ -2195,16 +2191,13 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
dentry = f.file->f_path.dentry;
if (*s) {
if (!d_can_lookup(dentry)) {
fdput(f);
return ERR_PTR(-ENOTDIR);
}
if (*s && unlikely(!d_can_lookup(dentry))) {
fdput(f);
return ERR_PTR(-ENOTDIR);
}
nd->path = f.file->f_path;
if (flags & LOOKUP_RCU) {
rcu_read_lock();
nd->inode = nd->path.dentry->d_inode;
nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
} else {
@ -2272,8 +2265,10 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path
const char *s = path_init(nd, flags);
int err;
if (IS_ERR(s))
if (IS_ERR(s)) {
terminate_walk(nd);
return PTR_ERR(s);
}
if (unlikely(flags & LOOKUP_DOWN)) {
err = handle_lookup_down(nd);
@ -2337,8 +2332,10 @@ static int path_parentat(struct nameidata *nd, unsigned flags,
{
const char *s = path_init(nd, flags);
int err;
if (IS_ERR(s))
if (IS_ERR(s)) {
terminate_walk(nd);
return PTR_ERR(s);
}
err = link_path_walk(s, nd);
if (!err)
err = complete_walk(nd);
@ -2666,8 +2663,10 @@ path_mountpoint(struct nameidata *nd, unsigned flags, struct path *path)
{
const char *s = path_init(nd, flags);
int err;
if (IS_ERR(s))
if (IS_ERR(s)) {
terminate_walk(nd);
return PTR_ERR(s);
}
while (!(err = link_path_walk(s, nd)) &&
(err = mountpoint_last(nd)) > 0) {
s = trailing_symlink(nd);
@ -3512,6 +3511,7 @@ static struct file *path_openat(struct nameidata *nd,
s = path_init(nd, flags);
if (IS_ERR(s)) {
terminate_walk(nd);
fput(file);
return ERR_CAST(s);
}