From 56b31d1c9f1e6a3ad92e7bfe252721e05d92b285 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 18 Aug 2012 00:25:51 -0400 Subject: [PATCH] unexport sock_map_fd(), switch to sock_alloc_file() Both modular callers of sock_map_fd() had been buggy; sctp one leaks descriptor and file if copy_to_user() fails, 9p one shouldn't be exposing file in the descriptor table at all. Switch both to sock_alloc_file(), export it, unexport sock_map_fd() and make it static. Signed-off-by: Al Viro --- include/linux/net.h | 3 ++- net/9p/trans_fd.c | 16 +++++++--------- net/sctp/socket.c | 25 ++++++++++++++++++++----- net/socket.c | 6 +++--- 4 files changed, 32 insertions(+), 18 deletions(-) diff --git a/include/linux/net.h b/include/linux/net.h index 99276c3..c8a9708 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -65,6 +65,7 @@ typedef enum { struct poll_table_struct; struct pipe_inode_info; struct inode; +struct file; struct net; #define SOCK_ASYNC_NOSPACE 0 @@ -246,7 +247,7 @@ extern int sock_sendmsg(struct socket *sock, struct msghdr *msg, size_t len); extern int sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int flags); -extern int sock_map_fd(struct socket *sock, int flags); +extern struct file *sock_alloc_file(struct socket *sock, int flags); extern struct socket *sockfd_lookup(int fd, int *err); extern struct socket *sock_from_file(struct file *file, int *err); #define sockfd_put(sock) fput(sock->file) diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index 6449bae..8c4e0b5 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -793,30 +793,28 @@ static int p9_fd_open(struct p9_client *client, int rfd, int wfd) static int p9_socket_open(struct p9_client *client, struct socket *csocket) { struct p9_trans_fd *p; - int ret, fd; + struct file *file; + int ret; p = kmalloc(sizeof(struct p9_trans_fd), GFP_KERNEL); if (!p) return -ENOMEM; csocket->sk->sk_allocation = GFP_NOIO; - fd = sock_map_fd(csocket, 0); - if (fd < 0) { + file = sock_alloc_file(csocket, 0); + if (IS_ERR(file)) { pr_err("%s (%d): failed to map fd\n", __func__, task_pid_nr(current)); sock_release(csocket); kfree(p); - return fd; + return PTR_ERR(file); } - get_file(csocket->file); - get_file(csocket->file); - p->wr = p->rd = csocket->file; + get_file(file); + p->wr = p->rd = file; client->trans = p; client->status = Connected; - sys_close(fd); /* still racy */ - p->rd->f_flags |= O_NONBLOCK; p->conn = p9_conn_create(client); diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 5e25981..fb5931c 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -70,6 +70,7 @@ #include #include #include +#include #include #include @@ -4276,6 +4277,7 @@ static int sctp_getsockopt_peeloff(struct sock *sk, int len, char __user *optval { sctp_peeloff_arg_t peeloff; struct socket *newsock; + struct file *newfile; int retval = 0; if (len < sizeof(sctp_peeloff_arg_t)) @@ -4289,22 +4291,35 @@ static int sctp_getsockopt_peeloff(struct sock *sk, int len, char __user *optval goto out; /* Map the socket to an unused fd that can be returned to the user. */ - retval = sock_map_fd(newsock, 0); + retval = get_unused_fd(); if (retval < 0) { sock_release(newsock); goto out; } + newfile = sock_alloc_file(newsock, 0); + if (unlikely(IS_ERR(newfile))) { + put_unused_fd(retval); + sock_release(newsock); + return PTR_ERR(newfile); + } + SCTP_DEBUG_PRINTK("%s: sk: %p newsk: %p sd: %d\n", __func__, sk, newsock->sk, retval); /* Return the fd mapped to the new socket. */ + if (put_user(len, optlen)) { + fput(newfile); + put_unused_fd(retval); + return -EFAULT; + } peeloff.sd = retval; - if (put_user(len, optlen)) + if (copy_to_user(optval, &peeloff, len)) { + fput(newfile); + put_unused_fd(retval); return -EFAULT; - if (copy_to_user(optval, &peeloff, len)) - retval = -EFAULT; - + } + fd_install(retval, newfile); out: return retval; } diff --git a/net/socket.c b/net/socket.c index a14ec19..38a1431 100644 --- a/net/socket.c +++ b/net/socket.c @@ -346,7 +346,7 @@ static struct file_system_type sock_fs_type = { * but we take care of internal coherence yet. */ -static struct file *sock_alloc_file(struct socket *sock, int flags) +struct file *sock_alloc_file(struct socket *sock, int flags) { struct qstr name = { .name = "" }; struct path path; @@ -375,8 +375,9 @@ static struct file *sock_alloc_file(struct socket *sock, int flags) file->private_data = sock; return file; } +EXPORT_SYMBOL(sock_alloc_file); -int sock_map_fd(struct socket *sock, int flags) +static int sock_map_fd(struct socket *sock, int flags) { struct file *newfile; int fd = get_unused_fd_flags(flags); @@ -392,7 +393,6 @@ int sock_map_fd(struct socket *sock, int flags) put_unused_fd(fd); return PTR_ERR(newfile); } -EXPORT_SYMBOL(sock_map_fd); struct socket *sock_from_file(struct file *file, int *err) { -- 2.7.4