redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

io_uring: fix sporadic -EFAULT from IORING_OP_RECVMSG 

If we have to punt the recvmsg to async context, we copy all the
context.  But since the iovec used can be either on-stack (if small) or
dynamically allocated, if it's on-stack, then we need to ensure we reset
the iov pointer. If we don't, then we're reusing old stack data, and
that can lead to -EFAULTs if things get overwritten.

Ensure we retain the right pointers for the iov, and free it as well if
we end up having to go beyond UIO_FASTIOV number of vectors.

Fixes: 03b1230ca1 ("io_uring: ensure async punted sendmsg/recvmsg requests copy data")
Reported-by: 李通洲 <carter.li@eoitek.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
alistair/sunxi64-5.5-dsi
Jens Axboe 2019-12-15 10:57:46 -07:00
parent d195a66e36
commit 0b416c3e13
1 changed files with 26 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
fs/io_uring.c
View File

@ -2041,6 +2041,7 @@ static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
struct io_kiocb **nxt, bool force_nonblock)
{
#if defined(CONFIG_NET)
struct io_async_msghdr *kmsg = NULL;
struct socket *sock;
int ret;
@ -2051,7 +2052,6 @@ static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
if (sock) {
struct io_async_ctx io, *copy;
struct sockaddr_storage addr;
struct msghdr *kmsg;
unsigned flags;
flags = READ_ONCE(sqe->msg_flags);
@ -2061,17 +2061,21 @@ static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
flags |= MSG_DONTWAIT;
if (req->io) {
kmsg = &req->io->msg.msg;
kmsg->msg_name = &addr;
kmsg = &req->io->msg;
kmsg->msg.msg_name = &addr;
/* if iov is set, it's allocated already */
if (!kmsg->iov)
kmsg->iov = kmsg->fast_iov;
kmsg->msg.msg_iter.iov = kmsg->iov;
} else {
kmsg = &io.msg.msg;
kmsg->msg_name = &addr;
kmsg = &io.msg;
kmsg->msg.msg_name = &addr;
ret = io_sendmsg_prep(req, &io);
if (ret)
goto out;
}
ret = __sys_sendmsg_sock(sock, kmsg, flags);
ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
if (force_nonblock && ret == -EAGAIN) {
copy = kmalloc(sizeof(*copy), GFP_KERNEL);
if (!copy) {
@ -2082,13 +2086,15 @@ static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
req->io = copy;
memcpy(&req->io->sqe, req->sqe, sizeof(*req->sqe));
req->sqe = &req->io->sqe;
return ret;
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
}
out:
if (kmsg && kmsg->iov != kmsg->fast_iov)
kfree(kmsg->iov);
io_cqring_add_event(req, ret);
if (ret < 0)
req_set_fail_links(req);
@ -2120,6 +2126,7 @@ static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
struct io_kiocb **nxt, bool force_nonblock)
{
#if defined(CONFIG_NET)
struct io_async_msghdr *kmsg = NULL;
struct socket *sock;
int ret;
@ -2131,7 +2138,6 @@ static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
struct user_msghdr __user *msg;
struct io_async_ctx io, *copy;
struct sockaddr_storage addr;
struct msghdr *kmsg;
unsigned flags;
flags = READ_ONCE(sqe->msg_flags);
@ -2143,17 +2149,21 @@ static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
msg = (struct user_msghdr __user *) (unsigned long)
READ_ONCE(sqe->addr);
if (req->io) {
kmsg = &req->io->msg.msg;
kmsg->msg_name = &addr;
kmsg = &req->io->msg;
kmsg->msg.msg_name = &addr;
/* if iov is set, it's allocated already */
if (!kmsg->iov)
kmsg->iov = kmsg->fast_iov;
kmsg->msg.msg_iter.iov = kmsg->iov;
} else {
kmsg = &io.msg.msg;
kmsg->msg_name = &addr;
kmsg = &io.msg;
kmsg->msg.msg_name = &addr;
ret = io_recvmsg_prep(req, &io);
if (ret)
goto out;
}
ret = __sys_recvmsg_sock(sock, kmsg, msg, io.msg.uaddr, flags);
ret = __sys_recvmsg_sock(sock, &kmsg->msg, msg, kmsg->uaddr, flags);
if (force_nonblock && ret == -EAGAIN) {
copy = kmalloc(sizeof(*copy), GFP_KERNEL);
if (!copy) {
@ -2164,13 +2174,15 @@ static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
req->io = copy;
memcpy(&req->io->sqe, req->sqe, sizeof(*req->sqe));
req->sqe = &req->io->sqe;
return ret;
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
}
out:
if (kmsg && kmsg->iov != kmsg->fast_iov)
kfree(kmsg->iov);
io_cqring_add_event(req, ret);
if (ret < 0)
req_set_fail_links(req);