* [PATCH] Btrfs: do not overwrite error return value in the device replace ioctl
@ 2018-12-14 19:45 fdmanana
2018-12-17 10:30 ` Anand Jain
2019-01-08 11:42 ` [PATCH v2] " fdmanana
0 siblings, 2 replies; 4+ messages in thread
From: fdmanana @ 2018-12-14 19:45 UTC (permalink / raw)
To: linux-btrfs
From: Filipe Manana <fdmanana@suse.com>
If the call to btrfs_dev_replace_by_ioctl() failed we would overwrite the
error returned to user space with -EFAULT if the call to copy_to_user()
failed as well. Fix that by calling copy_to_user() only if no error
happened before.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
fs/btrfs/ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0b101df822e9..abe45fd97ab5 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4401,7 +4401,7 @@ static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
break;
}
- if (copy_to_user(arg, p, sizeof(*p)))
+ if (ret == 0 && copy_to_user(arg, p, sizeof(*p)))
ret = -EFAULT;
out:
kfree(p);
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] Btrfs: do not overwrite error return value in the device replace ioctl
2018-12-14 19:45 [PATCH] Btrfs: do not overwrite error return value in the device replace ioctl fdmanana
@ 2018-12-17 10:30 ` Anand Jain
2019-01-08 11:42 ` [PATCH v2] " fdmanana
1 sibling, 0 replies; 4+ messages in thread
From: Anand Jain @ 2018-12-17 10:30 UTC (permalink / raw)
To: fdmanana, linux-btrfs
On 12/15/2018 03:45 AM, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> If the call to btrfs_dev_replace_by_ioctl() failed we would overwrite the
> error returned to user space with -EFAULT if the call to copy_to_user()
> failed as well. Fix that by calling copy_to_user() only if no error
> happened before.
>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
> ---
> fs/btrfs/ioctl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 0b101df822e9..abe45fd97ab5 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -4401,7 +4401,7 @@ static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
> break;
> }
>
> - if (copy_to_user(arg, p, sizeof(*p)))
> + if (ret == 0 && copy_to_user(arg, p, sizeof(*p)))
Its the same thing here too.. we copy ret to args->result even
if it fails. Now with this patch, if ret is non-zero, its not
in args->result at the userland anymore. If there
is any tool which just checks args->result will be at problem,
which I think is rare, should be ok. It would have been nice
to have this design as in this patch, in the original code.
------
530 ret = btrfs_dev_replace_start(fs_info,
args->start.tgtdev_name,
531 args->start.srcdevid,
532 args->start.srcdev_name,
533
args->start.cont_reading_from_srcdev_mode);
534 args->result = ret;
--------
> ret = -EFAULT;
> out:
> kfree(p);
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2] Btrfs: do not overwrite error return value in the device replace ioctl
2018-12-14 19:45 [PATCH] Btrfs: do not overwrite error return value in the device replace ioctl fdmanana
2018-12-17 10:30 ` Anand Jain
@ 2019-01-08 11:42 ` fdmanana
2019-01-08 15:57 ` David Sterba
1 sibling, 1 reply; 4+ messages in thread
From: fdmanana @ 2019-01-08 11:42 UTC (permalink / raw)
To: linux-btrfs
From: Filipe Manana <fdmanana@suse.com>
If the call to btrfs_dev_replace_by_ioctl() failed we would overwrite the
error returned to user space with -EFAULT if the call to copy_to_user()
failed as well. Fix that by calling copy_to_user() only if no error
happened before or a device replace operation was canceled.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
V2: Considered the case where the device replace operation is canceled.
fs/btrfs/ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 8dbb4ed07da1..0db60bfee99a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4462,7 +4462,7 @@ static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
break;
}
- if (copy_to_user(arg, p, sizeof(*p)))
+ if ((ret == 0 || ret == -ECANCELED) && copy_to_user(arg, p, sizeof(*p)))
ret = -EFAULT;
out:
kfree(p);
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] Btrfs: do not overwrite error return value in the device replace ioctl
2019-01-08 11:42 ` [PATCH v2] " fdmanana
@ 2019-01-08 15:57 ` David Sterba
0 siblings, 0 replies; 4+ messages in thread
From: David Sterba @ 2019-01-08 15:57 UTC (permalink / raw)
To: fdmanana; +Cc: linux-btrfs
On Tue, Jan 08, 2019 at 11:42:09AM +0000, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> If the call to btrfs_dev_replace_by_ioctl() failed we would overwrite the
> error returned to user space with -EFAULT if the call to copy_to_user()
> failed as well. Fix that by calling copy_to_user() only if no error
> happened before or a device replace operation was canceled.
>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-01-08 15:58 UTC | newest]
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2018-12-14 19:45 [PATCH] Btrfs: do not overwrite error return value in the device replace ioctl fdmanana
2018-12-17 10:30 ` Anand Jain
2019-01-08 11:42 ` [PATCH v2] " fdmanana
2019-01-08 15:57 ` David Sterba
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