[PATCH 9/9 net-next] net/socket: Use iovec_import() instead of import_iovec().

From: David Laight
Date: Tue Sep 15 2020 - 19:01:55 EST



iovec_import() has a safer calling convention than import_iovec().
Also contains a small change to fs/io_uring.c

Signed-off-by: David Laight <david.laight@xxxxxxxxxx>
---
fs/io_uring.c | 13 +++++++--
include/linux/socket.h | 15 +++++-----
include/net/compat.h | 5 ++--
net/compat.c | 17 +++++------
net/socket.c | 66 ++++++++++++++++++------------------------
5 files changed, 57 insertions(+), 59 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 0df43882e4b3..79707907e00d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4031,10 +4031,17 @@ static int io_setup_async_msg(struct io_kiocb *req,
static int io_sendmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
- iomsg->iov = iomsg->fast_iov;
+ struct iovec *iov;
+
iomsg->msg.msg_name = &iomsg->addr;
- return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg,
- req->sr_msg.msg_flags, &iomsg->iov);
+ iov = sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg,
+ req->sr_msg.msg_flags,
+ (void *)&iomsg->fast_iov);
+ if (IS_ERR(iov))
+ return PTR_ERR(iov);
+ /* Save any buffer that must be freed after the request completes. */
+ iomsg->iov = iov;
+ return 0;
}

static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
diff --git a/include/linux/socket.h b/include/linux/socket.h
index e9cb30d8cbfb..58d82ac014e2 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -398,13 +398,14 @@ extern long __sys_recvmsg_sock(struct socket *sock, struct msghdr *msg,
struct user_msghdr __user *umsg,
struct sockaddr __user *uaddr,
unsigned int flags);
-extern int sendmsg_copy_msghdr(struct msghdr *msg,
- struct user_msghdr __user *umsg, unsigned flags,
- struct iovec **iov);
-extern int recvmsg_copy_msghdr(struct msghdr *msg,
- struct user_msghdr __user *umsg, unsigned flags,
- struct sockaddr __user **uaddr,
- struct iovec **iov);
+struct iovec *sendmsg_copy_msghdr(struct msghdr *msg,
+ struct user_msghdr __user *umsg,
+ unsigned flags, struct iovec_cache *cache);
+struct iovec *recvmsg_copy_msghdr(struct msghdr *msg,
+ struct user_msghdr __user *umsg,
+ unsigned flags,
+ struct sockaddr __user **uaddr,
+ struct iovec_cache *cache);
extern int __copy_msghdr_from_user(struct msghdr *kmsg,
struct user_msghdr __user *umsg,
struct sockaddr __user **save_addr,
diff --git a/include/net/compat.h b/include/net/compat.h
index 745db0d605b6..61b8408e16b5 100644
--- a/include/net/compat.h
+++ b/include/net/compat.h
@@ -59,8 +59,9 @@ struct compat_rtentry {
int __get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg,
struct sockaddr __user **save_addr, compat_uptr_t *ptr,
compat_size_t *len);
-int get_compat_msghdr(struct msghdr *, struct compat_msghdr __user *,
- struct sockaddr __user **, struct iovec **);
+struct iovec *get_compat_msghdr(struct msghdr *, struct compat_msghdr __user *,
+ struct sockaddr __user **,
+ struct iovec_cache *);
int put_cmsg_compat(struct msghdr*, int, int, int, void *);

int cmsghdr_from_user_compat_to_kern(struct msghdr *, struct sock *,
diff --git a/net/compat.c b/net/compat.c
index 95ce707a30a3..3b37f6273891 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -85,22 +85,21 @@ int __get_compat_msghdr(struct msghdr *kmsg,
return 0;
}

-int get_compat_msghdr(struct msghdr *kmsg,
- struct compat_msghdr __user *umsg,
- struct sockaddr __user **save_addr,
- struct iovec **iov)
+struct iovec *get_compat_msghdr(struct msghdr *kmsg,
+ struct compat_msghdr __user *umsg,
+ struct sockaddr __user **save_addr,
+ struct iovec_cache *cache)
{
compat_uptr_t ptr;
compat_size_t len;
- ssize_t err;
+ int err;

err = __get_compat_msghdr(kmsg, umsg, save_addr, &ptr, &len);
if (err)
- return err;
+ return ERR_PTR(err);

- err = compat_import_iovec(save_addr ? READ : WRITE, compat_ptr(ptr),
- len, UIO_FASTIOV, iov, &kmsg->msg_iter);
- return err < 0 ? err : 0;
+ return compat_iovec_import(save_addr ? READ : WRITE, compat_ptr(ptr),
+ len, cache, &kmsg->msg_iter);
}

/* Bleech... */
diff --git a/net/socket.c b/net/socket.c
index 0c0144604f81..00feed199d53 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2275,10 +2275,10 @@ int __copy_msghdr_from_user(struct msghdr *kmsg,
return 0;
}

-static int copy_msghdr_from_user(struct msghdr *kmsg,
- struct user_msghdr __user *umsg,
- struct sockaddr __user **save_addr,
- struct iovec **iov)
+static struct iovec *copy_msghdr_from_user(struct msghdr *kmsg,
+ struct user_msghdr __user *umsg,
+ struct sockaddr __user **save_addr,
+ struct iovec_cache *cache)
{
struct user_msghdr msg;
ssize_t err;
@@ -2286,12 +2286,11 @@ static int copy_msghdr_from_user(struct msghdr *kmsg,
err = __copy_msghdr_from_user(kmsg, umsg, save_addr, &msg.msg_iov,
&msg.msg_iovlen);
if (err)
- return err;
+ return ERR_PTR(err);

- err = import_iovec(save_addr ? READ : WRITE,
+ return iovec_import(save_addr ? READ : WRITE,
msg.msg_iov, msg.msg_iovlen,
- UIO_FASTIOV, iov, &kmsg->msg_iter);
- return err < 0 ? err : 0;
+ cache, &kmsg->msg_iter);
}

static int ____sys_sendmsg(struct socket *sock, struct msghdr *msg_sys,
@@ -2369,24 +2368,18 @@ static int ____sys_sendmsg(struct socket *sock, struct msghdr *msg_sys,
return err;
}

-int sendmsg_copy_msghdr(struct msghdr *msg,
+struct iovec *sendmsg_copy_msghdr(struct msghdr *msg,
struct user_msghdr __user *umsg, unsigned flags,
- struct iovec **iov)
+ struct iovec_cache *cache)
{
- int err;
-
if (flags & MSG_CMSG_COMPAT) {
struct compat_msghdr __user *msg_compat;

msg_compat = (struct compat_msghdr __user *) umsg;
- err = get_compat_msghdr(msg, msg_compat, NULL, iov);
- } else {
- err = copy_msghdr_from_user(msg, umsg, NULL, iov);
+ return get_compat_msghdr(msg, msg_compat, NULL, cache);
}
- if (err < 0)
- return err;

- return 0;
+ return copy_msghdr_from_user(msg, umsg, NULL, cache);
}

static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
@@ -2395,14 +2388,15 @@ static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
unsigned int allowed_msghdr_flags)
{
struct sockaddr_storage address;
- struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
+ struct iovec_cache cache;
+ struct iovec *iov;
ssize_t err;

msg_sys->msg_name = &address;

- err = sendmsg_copy_msghdr(msg_sys, msg, flags, &iov);
- if (err < 0)
- return err;
+ iov = sendmsg_copy_msghdr(msg_sys, msg, flags, &cache);
+ if (IS_ERR(iov))
+ return PTR_ERR(iov);

err = ____sys_sendmsg(sock, msg_sys, flags, used_address,
allowed_msghdr_flags);
@@ -2526,25 +2520,20 @@ SYSCALL_DEFINE4(sendmmsg, int, fd, struct mmsghdr __user *, mmsg,
return __sys_sendmmsg(fd, mmsg, vlen, flags, true);
}

-int recvmsg_copy_msghdr(struct msghdr *msg,
- struct user_msghdr __user *umsg, unsigned flags,
- struct sockaddr __user **uaddr,
- struct iovec **iov)
+struct iovec *recvmsg_copy_msghdr(struct msghdr *msg,
+ struct user_msghdr __user *umsg,
+ unsigned flags,
+ struct sockaddr __user **uaddr,
+ struct iovec_cache *cache)
{
- ssize_t err;
-
if (MSG_CMSG_COMPAT & flags) {
struct compat_msghdr __user *msg_compat;

msg_compat = (struct compat_msghdr __user *) umsg;
- err = get_compat_msghdr(msg, msg_compat, uaddr, iov);
- } else {
- err = copy_msghdr_from_user(msg, umsg, uaddr, iov);
+ return get_compat_msghdr(msg, msg_compat, uaddr, cache);
}
- if (err < 0)
- return err;

- return 0;
+ return copy_msghdr_from_user(msg, umsg, uaddr, cache);
}

static int ____sys_recvmsg(struct socket *sock, struct msghdr *msg_sys,
@@ -2606,14 +2595,15 @@ static int ____sys_recvmsg(struct socket *sock, struct msghdr *msg_sys,
static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
struct msghdr *msg_sys, unsigned int flags, int nosec)
{
- struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
+ struct iovec_cache cache;
+ struct iovec *iov;
/* user mode address pointers */
struct sockaddr __user *uaddr;
ssize_t err;

- err = recvmsg_copy_msghdr(msg_sys, msg, flags, &uaddr, &iov);
- if (err < 0)
- return err;
+ iov = recvmsg_copy_msghdr(msg_sys, msg, flags, &uaddr, &cache);
+ if (IS_ERR(iov))
+ return PTR_ERR(iov);

err = ____sys_recvmsg(sock, msg_sys, msg, uaddr, flags, nosec);
kfree(iov);
--
2.25.1

-
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