* [PATCH] net: fix compat pointer in get_compat_msghdr()
@ 2022-07-15 22:03 Jens Axboe
[not found] ` <CGME20220716204701eucas1p1cd9d17857b50339074b22320373ef1b6@eucas1p1.samsung.com>
0 siblings, 1 reply; 2+ messages in thread
From: Jens Axboe @ 2022-07-15 22:03 UTC (permalink / raw)
To: io-uring, netdev; +Cc: Dylan Yudaken
A previous change enabled external users to copy the data before
calling __get_compat_msghdr(), but didn't modify get_compat_msghdr() or
__io_compat_recvmsg_copy_hdr() to take that into account. They are both
stil passing in the __user pointer rather than the copied version.
Ensure we pass in the kernel struct, not the pointer to the user data.
Link: https://lore.kernel.org/all/[email protected]/
Fixes: 1a3e4e94a1b9 ("net: copy from user before calling __get_compat_msghdr")
Reported-by: Marek Szyprowski <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
As this was staged in the io_uring tree, I plan on applying this fix
there as well. Holler if anyone disagrees.
diff --git a/io_uring/net.c b/io_uring/net.c
index 6b7d5f33e642..e61efa31c729 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -398,7 +398,7 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg)))
return -EFAULT;
- ret = __get_compat_msghdr(&iomsg->msg, sr->umsg_compat, &iomsg->uaddr);
+ ret = __get_compat_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
if (ret)
return ret;
diff --git a/net/compat.c b/net/compat.c
index 513aa9a3fc64..ed880729d159 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -89,7 +89,7 @@ int get_compat_msghdr(struct msghdr *kmsg,
if (copy_from_user(&msg, umsg, sizeof(*umsg)))
return -EFAULT;
- err = __get_compat_msghdr(kmsg, umsg, save_addr);
+ err = __get_compat_msghdr(kmsg, &msg, save_addr);
if (err)
return err;
--
Jens Axboe
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] net: fix compat pointer in get_compat_msghdr()
[not found] ` <CGME20220716204701eucas1p1cd9d17857b50339074b22320373ef1b6@eucas1p1.samsung.com>
@ 2022-07-16 20:47 ` Marek Szyprowski
0 siblings, 0 replies; 2+ messages in thread
From: Marek Szyprowski @ 2022-07-16 20:47 UTC (permalink / raw)
To: Jens Axboe, io-uring, netdev; +Cc: Dylan Yudaken
On 16.07.2022 00:03, Jens Axboe wrote:
> A previous change enabled external users to copy the data before
> calling __get_compat_msghdr(), but didn't modify get_compat_msghdr() or
> __io_compat_recvmsg_copy_hdr() to take that into account. They are both
> stil passing in the __user pointer rather than the copied version.
>
> Ensure we pass in the kernel struct, not the pointer to the user data.
>
> Link: https://lore.kernel.org/all/[email protected]/
> Fixes: 1a3e4e94a1b9 ("net: copy from user before calling __get_compat_msghdr")
> Reported-by: Marek Szyprowski <[email protected]>
> Signed-off-by: Jens Axboe <[email protected]>
This fixes the issue I've reported.
Tested-by: Marek Szyprowski <[email protected]>
> ---
>
> As this was staged in the io_uring tree, I plan on applying this fix
> there as well. Holler if anyone disagrees.
>
> diff --git a/io_uring/net.c b/io_uring/net.c
> index 6b7d5f33e642..e61efa31c729 100644
> --- a/io_uring/net.c
> +++ b/io_uring/net.c
> @@ -398,7 +398,7 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
> if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg)))
> return -EFAULT;
>
> - ret = __get_compat_msghdr(&iomsg->msg, sr->umsg_compat, &iomsg->uaddr);
> + ret = __get_compat_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
> if (ret)
> return ret;
>
> diff --git a/net/compat.c b/net/compat.c
> index 513aa9a3fc64..ed880729d159 100644
> --- a/net/compat.c
> +++ b/net/compat.c
> @@ -89,7 +89,7 @@ int get_compat_msghdr(struct msghdr *kmsg,
> if (copy_from_user(&msg, umsg, sizeof(*umsg)))
> return -EFAULT;
>
> - err = __get_compat_msghdr(kmsg, umsg, save_addr);
> + err = __get_compat_msghdr(kmsg, &msg, save_addr);
> if (err)
> return err;
>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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2022-07-15 22:03 [PATCH] net: fix compat pointer in get_compat_msghdr() Jens Axboe
[not found] ` <CGME20220716204701eucas1p1cd9d17857b50339074b22320373ef1b6@eucas1p1.samsung.com>
2022-07-16 20:47 ` Marek Szyprowski
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