socketpair(): allocate descriptors first

simplifies failure exits considerably...

Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Al Viro 2017-12-05 23:28:38 +00:00 committed by David S. Miller
parent a5739435b5
commit 016a266bdf
1 changed files with 39 additions and 52 deletions

View File

@ -1365,88 +1365,75 @@ SYSCALL_DEFINE4(socketpair, int, family, int, type, int, protocol,
if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
/*
* reserve descriptors and make sure we won't fail
* to return them to userland.
*/
fd1 = get_unused_fd_flags(flags);
if (unlikely(fd1 < 0))
return fd1;
fd2 = get_unused_fd_flags(flags);
if (unlikely(fd2 < 0)) {
put_unused_fd(fd1);
return fd2;
}
err = put_user(fd1, &usockvec[0]);
if (err)
goto out;
err = put_user(fd2, &usockvec[1]);
if (err)
goto out;
/*
* Obtain the first socket and check if the underlying protocol
* supports the socketpair call.
*/
err = sock_create(family, type, protocol, &sock1);
if (err < 0)
if (unlikely(err < 0))
goto out;
err = sock_create(family, type, protocol, &sock2);
if (err < 0)
goto out_release_1;
err = sock1->ops->socketpair(sock1, sock2);
if (err < 0)
goto out_release_both;
fd1 = get_unused_fd_flags(flags);
if (unlikely(fd1 < 0)) {
err = fd1;
goto out_release_both;
if (unlikely(err < 0)) {
sock_release(sock1);
goto out;
}
fd2 = get_unused_fd_flags(flags);
if (unlikely(fd2 < 0)) {
err = fd2;
goto out_put_unused_1;
err = sock1->ops->socketpair(sock1, sock2);
if (unlikely(err < 0)) {
sock_release(sock2);
sock_release(sock1);
goto out;
}
newfile1 = sock_alloc_file(sock1, flags, NULL);
if (IS_ERR(newfile1)) {
err = PTR_ERR(newfile1);
goto out_put_unused_both;
sock_release(sock1);
sock_release(sock2);
goto out;
}
newfile2 = sock_alloc_file(sock2, flags, NULL);
if (IS_ERR(newfile2)) {
err = PTR_ERR(newfile2);
goto out_fput_1;
sock_release(sock2);
fput(newfile1);
goto out;
}
err = put_user(fd1, &usockvec[0]);
if (err)
goto out_fput_both;
err = put_user(fd2, &usockvec[1]);
if (err)
goto out_fput_both;
audit_fd_pair(fd1, fd2);
fd_install(fd1, newfile1);
fd_install(fd2, newfile2);
/* fd1 and fd2 may be already another descriptors.
* Not kernel problem.
*/
return 0;
out_fput_both:
fput(newfile2);
fput(newfile1);
put_unused_fd(fd2);
put_unused_fd(fd1);
goto out;
out_fput_1:
fput(newfile1);
put_unused_fd(fd2);
put_unused_fd(fd1);
sock_release(sock2);
goto out;
out_put_unused_both:
put_unused_fd(fd2);
out_put_unused_1:
put_unused_fd(fd1);
out_release_both:
sock_release(sock2);
out_release_1:
sock_release(sock1);
out:
put_unused_fd(fd2);
put_unused_fd(fd1);
return err;
}