From: jeffy <jeffy.chen@rock-chips.com>
To: Jeffy Chen <jeffy.chen@rock-chips.com>, linux-kernel@vger.kernel.org
Cc: briannorris@chromium.org, dianders@chromium.org,
dri-devel@lists.freedesktop.org,
Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: drm: Add missing field copy in compat_drm_version
Date: Thu, 13 Jul 2017 10:20:20 +0800 [thread overview]
Message-ID: <5966D8E4.3050907@rock-chips.com> (raw)
In-Reply-To: <1499840312-23418-1-git-send-email-jeffy.chen@rock-chips.com>
Hi guys,
i was testing this on arm64 base chromeos(with arm32 userspace).
and the libdrm crashed:
drmVersionPtr drmGetVersion(int fd)
{
...
memclear(*version);
if (drmIoctl(fd, DRM_IOCTL_VERSION, version)) {
...
if (version->name_len)
version->name = drmMalloc(version->name_len + 1); <--
rely on the lengths updated by kernel
if (version->date_len)
version->date = drmMalloc(version->date_len + 1);
if (version->desc_len)
version->desc = drmMalloc(version->desc_len + 1);
...
if (version->name_len) version->name[version->name_len] = '\0';
<-- crashed here, since the name_len would always be zero, so
version->name would be nullptr.
On 07/12/2017 02:18 PM, Jeffy Chen wrote:
> DRM_IOCTL_VERSION is supposed to update the name_len/date_len/desc_len
> fields to user.
>
> Fixes: 012c6741c6aa("switch compat_drm_version() to drm_ioctl_kernel()")
> Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
> ---
>
> drivers/gpu/drm/drm_ioc32.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_ioc32.c b/drivers/gpu/drm/drm_ioc32.c
> index 94acf51..2789356 100644
> --- a/drivers/gpu/drm/drm_ioc32.c
> +++ b/drivers/gpu/drm/drm_ioc32.c
> @@ -112,6 +112,9 @@ static int compat_drm_version(struct file *file, unsigned int cmd,
> v32.version_major = v.version_major;
> v32.version_minor = v.version_minor;
> v32.version_patchlevel = v.version_patchlevel;
> + v32.name_len = v.name_len;
> + v32.date_len = v.date_len;
> + v32.desc_len = v.desc_len;
> if (copy_to_user((void __user *)arg, &v32, sizeof(v32)))
> return -EFAULT;
> return 0;
>
>
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WARNING: multiple messages have this Message-ID (diff)
From: jeffy <jeffy.chen@rock-chips.com>
To: Jeffy Chen <jeffy.chen@rock-chips.com>, linux-kernel@vger.kernel.org
Cc: briannorris@chromium.org, dianders@chromium.org,
Daniel Vetter <daniel.vetter@intel.com>,
Jani Nikula <jani.nikula@linux.intel.com>,
dri-devel@lists.freedesktop.org, David Airlie <airlied@linux.ie>,
Sean Paul <seanpaul@chromium.org>
Subject: Re: drm: Add missing field copy in compat_drm_version
Date: Thu, 13 Jul 2017 10:20:20 +0800 [thread overview]
Message-ID: <5966D8E4.3050907@rock-chips.com> (raw)
In-Reply-To: <1499840312-23418-1-git-send-email-jeffy.chen@rock-chips.com>
Hi guys,
i was testing this on arm64 base chromeos(with arm32 userspace).
and the libdrm crashed:
drmVersionPtr drmGetVersion(int fd)
{
...
memclear(*version);
if (drmIoctl(fd, DRM_IOCTL_VERSION, version)) {
...
if (version->name_len)
version->name = drmMalloc(version->name_len + 1); <--
rely on the lengths updated by kernel
if (version->date_len)
version->date = drmMalloc(version->date_len + 1);
if (version->desc_len)
version->desc = drmMalloc(version->desc_len + 1);
...
if (version->name_len) version->name[version->name_len] = '\0';
<-- crashed here, since the name_len would always be zero, so
version->name would be nullptr.
On 07/12/2017 02:18 PM, Jeffy Chen wrote:
> DRM_IOCTL_VERSION is supposed to update the name_len/date_len/desc_len
> fields to user.
>
> Fixes: 012c6741c6aa("switch compat_drm_version() to drm_ioctl_kernel()")
> Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
> ---
>
> drivers/gpu/drm/drm_ioc32.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_ioc32.c b/drivers/gpu/drm/drm_ioc32.c
> index 94acf51..2789356 100644
> --- a/drivers/gpu/drm/drm_ioc32.c
> +++ b/drivers/gpu/drm/drm_ioc32.c
> @@ -112,6 +112,9 @@ static int compat_drm_version(struct file *file, unsigned int cmd,
> v32.version_major = v.version_major;
> v32.version_minor = v.version_minor;
> v32.version_patchlevel = v.version_patchlevel;
> + v32.name_len = v.name_len;
> + v32.date_len = v.date_len;
> + v32.desc_len = v.desc_len;
> if (copy_to_user((void __user *)arg, &v32, sizeof(v32)))
> return -EFAULT;
> return 0;
>
>
next prev parent reply other threads:[~2017-07-13 2:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-12 6:18 [PATCH] drm: Add missing field copy in compat_drm_version Jeffy Chen
2017-07-13 2:20 ` jeffy [this message]
2017-07-13 2:20 ` jeffy
2017-07-13 12:36 ` [PATCH] " Daniel Vetter
2017-07-13 12:36 ` Daniel Vetter
2017-07-14 1:39 ` Al Viro
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