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authorAl Viro <viro@zeniv.linux.org.uk>2021-06-19 06:50:31 +0300
committerDavid S. Miller <davem@davemloft.net>2021-06-21 22:28:49 +0300
commit56c1731b280dc71febf5df80fcac1923ea973ab8 (patch)
treeed136ef1746c3fa21591d55acff0ef36c4c84294 /net
parent71e6be6f7d2bada7099d79205779c4452d4fd35b (diff)
downloadlinux-56c1731b280dc71febf5df80fcac1923ea973ab8.tar.xz
unix_bind_bsd(): move done_path_create() call after dealing with ->bindlock
Final preparations for doing unlink on failure past the successful mknod. We can't hold ->bindlock over ->mknod() or ->unlink(), since either might do sb_start_write() (e.g. on overlayfs). However, we can do it while holding filesystem and VFS locks - doing kern_path_create() vfs_mknod() grab ->bindlock if u->addr had been set drop ->bindlock done_path_create return -EINVAL else assign the address to socket drop ->bindlock done_path_create return 0 would be deadlock-free. Here we massage unix_bind_bsd() to that form. We are still doing equivalent transformations. Next commit will *not* be an equivalent transformation - it will add a call of vfs_unlink() before done_path_create() in "alread bound" case. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/unix/af_unix.c26
1 files changed, 11 insertions, 15 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index fe337dc98400..25dda9ca9d15 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -989,8 +989,8 @@ static int unix_bind_bsd(struct sock *sk, struct unix_address *addr)
struct unix_sock *u = unix_sk(sk);
umode_t mode = S_IFSOCK |
(SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask());
- struct path parent, path;
struct user_namespace *ns; // barf...
+ struct path parent;
struct dentry *dentry;
unsigned int hash;
int err;
@@ -1008,36 +1008,32 @@ static int unix_bind_bsd(struct sock *sk, struct unix_address *addr)
* All right, let's create it.
*/
err = security_path_mknod(&parent, dentry, mode, 0);
- if (!err) {
+ if (!err)
err = vfs_mknod(ns, d_inode(parent.dentry), dentry, mode, 0);
- if (!err) {
- path.mnt = mntget(parent.mnt);
- path.dentry = dget(dentry);
- }
- }
- done_path_create(&parent, dentry);
- if (err)
+ if (err) {
+ done_path_create(&parent, dentry);
return err;
-
+ }
err = mutex_lock_interruptible(&u->bindlock);
if (err) {
- path_put(&path);
+ done_path_create(&parent, dentry);
return err;
}
-
if (u->addr) {
mutex_unlock(&u->bindlock);
- path_put(&path);
+ done_path_create(&parent, dentry);
return -EINVAL;
}
addr->hash = UNIX_HASH_SIZE;
- hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
+ hash = d_backing_inode(dentry)->i_ino & (UNIX_HASH_SIZE - 1);
spin_lock(&unix_table_lock);
- u->path = path;
+ u->path.mnt = mntget(parent.mnt);
+ u->path.dentry = dget(dentry);
__unix_set_addr(sk, addr, hash);
spin_unlock(&unix_table_lock);
mutex_unlock(&u->bindlock);
+ done_path_create(&parent, dentry);
return 0;
}