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io_uring/net: fix cleanup double free free_iov init

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Having ->async_data doesn't mean it's initialised and previously we vere
relying on setting F_CLEANUP at the right moment. With zc sendmsg
though, we set F_CLEANUP early in prep when we alloc a notif and so we
may allocate async_data, fail in copy_msg_hdr() leaving
struct io_async_msghdr not initialised correctly but with F_CLEANUP
set, which causes a ->free_iov double free and probably other nastiness.

Always initialise ->free_iov. Also, now it might point to fast_iov when
fails, so avoid freeing it during cleanups.

Reported-by: syzbot+edfd15cd4246a3fc615a@syzkaller.appspotmail.com
Fixes: 493108d95f ("io_uring/net: zerocopy sendmsg")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2022-09-26 14:35:09 +01:00 committed by Jens Axboe
parent aa1df3a360
commit 4c17a496a7
1 changed files with 10 additions and 10 deletions
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20
io_uring/net.c
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@ -124,20 +124,22 @@ static struct io_async_msghdr *io_msg_alloc_async(struct io_kiocb *req,
{
struct io_ring_ctx *ctx = req->ctx;
struct io_cache_entry *entry;
struct io_async_msghdr *hdr;
if (!(issue_flags & IO_URING_F_UNLOCKED) &&
(entry = io_alloc_cache_get(&ctx->netmsg_cache)) != NULL) {
struct io_async_msghdr *hdr;
hdr = container_of(entry, struct io_async_msghdr, cache);
hdr->free_iov = NULL;
req->flags |= REQ_F_ASYNC_DATA;
req->async_data = hdr;
return hdr;
}
if (!io_alloc_async_data(req))
return req->async_data;
if (!io_alloc_async_data(req)) {
hdr = req->async_data;
hdr->free_iov = NULL;
return hdr;
}
return NULL;
}
@ -192,7 +194,6 @@ int io_send_prep_async(struct io_kiocb *req)
io = io_msg_alloc_async_prep(req);
if (!io)
return -ENOMEM;
io->free_iov = NULL;
ret = move_addr_to_kernel(zc->addr, zc->addr_len, &io->addr);
return ret;
}
@ -209,7 +210,6 @@ static int io_setup_async_addr(struct io_kiocb *req,
io = io_msg_alloc_async(req, issue_flags);
if (!io)
return -ENOMEM;
io->free_iov = NULL;
memcpy(&io->addr, addr_storage, sizeof(io->addr));
return -EAGAIN;
}
@ -479,7 +479,6 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
if (msg.msg_iovlen == 0) {
sr->len = 0;
iomsg->free_iov = NULL;
} else if (msg.msg_iovlen > 1) {
return -EINVAL;
} else {
@ -490,7 +489,6 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
if (clen < 0)
return -EINVAL;
sr->len = clen;
iomsg->free_iov = NULL;
}
if (req->flags & REQ_F_APOLL_MULTISHOT) {
@ -913,7 +911,9 @@ void io_send_zc_cleanup(struct io_kiocb *req)
if (req_has_async_data(req)) {
io = req->async_data;
kfree(io->free_iov);
/* might be ->fast_iov if *msg_copy_hdr failed */
if (io->free_iov != io->fast_iov)
kfree(io->free_iov);
}
if (zc->notif) {
zc->notif->flags |= REQ_F_CQE_SKIP;