[PATCH 6.7 118/713] io_uring/net: move receive multishot out of the generic msghdr path

Sasha Levin
2024-03-24T22:49:17Z

From: Jens Axboe <axboe@kernel.dk>

[ Upstream commit c55978024d123d43808ab393a0a4ce3ce8568150 ]

Move the actual user_msghdr / compat_msghdr into the send and receive
sides, respectively, so we can move the uaddr receive handling into its
own handler, and ditto the multishot with buffer selection logic.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: 8ede3db5061b ("io_uring/net: fix overflow check in io_recvmsg_mshot_prep()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
io_uring/net.c | 161 ++++++++++++++++++++++++++++---------------------
1 file changed, 91 insertions(+), 70 deletions(-)

diff --git a/io_uring/net.c b/io_uring/net.c
index ef495e2aac2bc..1d9bfde71809a 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -204,46 +204,26 @@ static int io_setup_async_msg(struct io_kiocb *req,
return -EAGAIN;
}

-static bool io_recvmsg_multishot_overflow(struct io_async_msghdr *iomsg)
-{
- int hdr;
-
- if (iomsg->namelen < 0)
- return true;
- if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
- iomsg->namelen, &hdr))
- return true;
- if (check_add_overflow(hdr, (int)iomsg->controllen, &hdr))
- return true;
-
- return false;
-}
-
#ifdef CONFIG_COMPAT
-static int __io_compat_msg_copy_hdr(struct io_kiocb *req,
- struct io_async_msghdr *iomsg,
- struct sockaddr __user **addr, int ddir)
+static int io_compat_msg_copy_hdr(struct io_kiocb *req,
+ struct io_async_msghdr *iomsg,
+ struct compat_msghdr *msg, int ddir)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
- struct compat_msghdr msg;
struct compat_iovec __user *uiov;
int ret;

- if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg)))
+ if (copy_from_user(msg, sr->umsg_compat, sizeof(*msg)))
return -EFAULT;

- ret = __get_compat_msghdr(&iomsg->msg, &msg, addr);
- if (ret)
- return ret;
-
- uiov = compat_ptr(msg.msg_iov);
+ uiov = compat_ptr(msg->msg_iov);
if (req->flags & REQ_F_BUFFER_SELECT) {
compat_ssize_t clen;

iomsg->free_iov = NULL;
- if (msg.msg_iovlen == 0) {
+ if (msg->msg_iovlen == 0) {
sr->len = 0;
- } else if (msg.msg_iovlen > 1) {
+ } else if (msg->msg_iovlen > 1) {
return -EINVAL;
} else {
if (!access_ok(uiov, sizeof(*uiov)))
@@ -255,18 +235,11 @@ static int __io_compat_msg_copy_hdr(struct io_kiocb *req,
sr->len = clen;
}

- if (ddir == ITER_DEST && req->flags & REQ_F_APOLL_MULTISHOT) {
- iomsg->namelen = msg.msg_namelen;
- iomsg->controllen = msg.msg_controllen;
- if (io_recvmsg_multishot_overflow(iomsg))
- return -EOVERFLOW;
- }
-
return 0;
}

iomsg->free_iov = iomsg->fast_iov;
- ret = __import_iovec(ddir, (struct iovec __user *)uiov, msg.msg_iovlen,
+ ret = __import_iovec(ddir, (struct iovec __user *)uiov, msg->msg_iovlen,
UIO_FASTIOV, &iomsg->free_iov,
&iomsg->msg.msg_iter, true);
if (unlikely(ret < 0))
@@ -276,47 +249,35 @@ static int __io_compat_msg_copy_hdr(struct io_kiocb *req,
}
#endif

-static int __io_msg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg,
- struct sockaddr __user **addr, int ddir)
+static int io_msg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg,
+ struct user_msghdr *msg, int ddir)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
- struct user_msghdr msg;
int ret;

- if (copy_from_user(&msg, sr->umsg, sizeof(*sr->umsg)))
+ if (copy_from_user(msg, sr->umsg, sizeof(*sr->umsg)))
return -EFAULT;

- ret = __copy_msghdr(&iomsg->msg, &msg, addr);
- if (ret)
- return ret;
-
if (req->flags & REQ_F_BUFFER_SELECT) {
- if (msg.msg_iovlen == 0) {
+ if (msg->msg_iovlen == 0) {
sr->len = iomsg->fast_iov[0].iov_len = 0;
iomsg->fast_iov[0].iov_base = NULL;
iomsg->free_iov = NULL;
- } else if (msg.msg_iovlen > 1) {
+ } else if (msg->msg_iovlen > 1) {
return -EINVAL;
} else {
- if (copy_from_user(iomsg->fast_iov, msg.msg_iov,
- sizeof(*msg.msg_iov)))
+ if (copy_from_user(iomsg->fast_iov, msg->msg_iov,
+ sizeof(*msg->msg_iov)))
return -EFAULT;
sr->len = iomsg->fast_iov[0].iov_len;
iomsg->free_iov = NULL;
}

- if (ddir == ITER_DEST && req->flags & REQ_F_APOLL_MULTISHOT) {
- iomsg->namelen = msg.msg_namelen;
- iomsg->controllen = msg.msg_controllen;
- if (io_recvmsg_multishot_overflow(iomsg))
- return -EOVERFLOW;
- }
-
return 0;
}

iomsg->free_iov = iomsg->fast_iov;
- ret = __import_iovec(ddir, msg.msg_iov, msg.msg_iovlen, UIO_FASTIOV,
+ ret = __import_iovec(ddir, msg->msg_iov, msg->msg_iovlen, UIO_FASTIOV,
&iomsg->free_iov, &iomsg->msg.msg_iter, false);
if (unlikely(ret < 0))
return ret;
@@ -324,30 +285,34 @@ static int __io_msg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg
return 0;
}

-static int io_msg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg,
- struct sockaddr __user **addr, int ddir)
+static int io_sendmsg_copy_hdr(struct io_kiocb *req,
+ struct io_async_msghdr *iomsg)
{
+ struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
+ struct user_msghdr msg;
+ int ret;
+
iomsg->msg.msg_name = &iomsg->addr;
iomsg->msg.msg_iter.nr_segs = 0;

#ifdef CONFIG_COMPAT
- if (req->ctx->compat)
- return __io_compat_msg_copy_hdr(req, iomsg, addr, ddir);
-#endif
+ if (unlikely(req->ctx->compat)) {
+ struct compat_msghdr cmsg;

- return __io_msg_copy_hdr(req, iomsg, addr, ddir);
-}
+ ret = io_compat_msg_copy_hdr(req, iomsg, &cmsg, ITER_SOURCE);
+ if (unlikely(ret))
+ return ret;

-static int io_sendmsg_copy_hdr(struct io_kiocb *req,
- struct io_async_msghdr *iomsg)
-{
- struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
- int ret;
+ return __get_compat_msghdr(&iomsg->msg, &cmsg, NULL);
+ }
+#endif

- ret = io_msg_copy_hdr(req, iomsg, NULL, ITER_SOURCE);
- if (ret)
+ ret = io_msg_copy_hdr(req, iomsg, &msg, ITER_SOURCE);
+ if (unlikely(ret))
return ret;

+ ret = __copy_msghdr(&iomsg->msg, &msg, NULL);
+
/* save msg_control as sys_sendmsg() overwrites it */
sr->msg_control = iomsg->msg.msg_control_user;
return ret;
@@ -569,10 +534,66 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags)
return IOU_OK;
}

+static int io_recvmsg_mshot_prep(struct io_kiocb *req,
+ struct io_async_msghdr *iomsg,
+ size_t namelen, size_t controllen)
+{
+ if ((req->flags & (REQ_F_APOLL_MULTISHOT|REQ_F_BUFFER_SELECT)) ==
+ (REQ_F_APOLL_MULTISHOT|REQ_F_BUFFER_SELECT)) {
+ int hdr;
+
+ if (unlikely(namelen < 0))
+ return -EOVERFLOW;
+ if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
+ namelen, &hdr))
+ return -EOVERFLOW;
+ if (check_add_overflow(hdr, (int)controllen, &hdr))
+ return -EOVERFLOW;
+
+ iomsg->namelen = namelen;
+ iomsg->controllen = controllen;
+ return 0;
+ }
+
+ return 0;
+}
+
static int io_recvmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
- return io_msg_copy_hdr(req, iomsg, &iomsg->uaddr, ITER_DEST);
+ struct user_msghdr msg;
+ int ret;
+
+ iomsg->msg.msg_name = &iomsg->addr;
+ iomsg->msg.msg_iter.nr_segs = 0;
+
+#ifdef CONFIG_COMPAT
+ if (unlikely(req->ctx->compat)) {
+ struct compat_msghdr cmsg;
+
+ ret = io_compat_msg_copy_hdr(req, iomsg, &cmsg, ITER_DEST);
+ if (unlikely(ret))
+ return ret;
+
+ ret = __get_compat_msghdr(&iomsg->msg, &cmsg, &iomsg->uaddr);
+ if (unlikely(ret))
+ return ret;
+
+ return io_recvmsg_mshot_prep(req, iomsg, cmsg.msg_namelen,
+ cmsg.msg_controllen);
+ }
+#endif
+
+ ret = io_msg_copy_hdr(req, iomsg, &msg, ITER_DEST);
+ if (unlikely(ret))
+ return ret;
+
+ ret = __copy_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
+ if (unlikely(ret))
+ return ret;
+
+ return io_recvmsg_mshot_prep(req, iomsg, msg.msg_namelen,
+ msg.msg_controllen);
}

int io_recvmsg_prep_async(struct io_kiocb *req)
--
2.43.0