Re: [PATCH v2] drm: remove redundant code form drm_ioc32.c

From: Daniel Vetter
Date: Fri Jul 03 2015 - 07:54:12 EST

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On Fri, Jul 03, 2015 at 02:17:29PM +0300, Jarkko Sakkinen wrote:
> The compat ioctl handler ends up calling access_ok() twice: first
> indirectly inside compat_alloc_user_space() and then after returning
> from that function. This patch fixes issue.
>
> v2: there were three invalid removals of access_ok() that I've fixed.
> Also went through all the changes couple of times and verified that
> access_ok() is only removed when the buffer is allocated with
> compat_alloc_user_space(). My deepest apologies for this kind of
> sloppiness!
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>

Merged again, thanks for the update.
-Daniel

> ---
> drivers/gpu/drm/drm_ioc32.c | 55 +++++++++++++++++++++------------------------
> 1 file changed, 26 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_ioc32.c b/drivers/gpu/drm/drm_ioc32.c
> index aa8bbb4..8dcfa76 100644
> --- a/drivers/gpu/drm/drm_ioc32.c
> +++ b/drivers/gpu/drm/drm_ioc32.c
> @@ -93,7 +93,7 @@ static int compat_drm_version(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> version = compat_alloc_user_space(sizeof(*version));
> - if (!access_ok(VERIFY_WRITE, version, sizeof(*version)))
> + if (!version)
> return -EFAULT;
> if (__put_user(v32.name_len, &version->name_len)
> || __put_user((void __user *)(unsigned long)v32.name,
> @@ -140,7 +140,7 @@ static int compat_drm_getunique(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> u = compat_alloc_user_space(sizeof(*u));
> - if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
> + if (!u)
> return -EFAULT;
> if (__put_user(uq32.unique_len, &u->unique_len)
> || __put_user((void __user *)(unsigned long)uq32.unique,
> @@ -168,7 +168,7 @@ static int compat_drm_setunique(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> u = compat_alloc_user_space(sizeof(*u));
> - if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
> + if (!u)
> return -EFAULT;
> if (__put_user(uq32.unique_len, &u->unique_len)
> || __put_user((void __user *)(unsigned long)uq32.unique,
> @@ -200,7 +200,7 @@ static int compat_drm_getmap(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> map = compat_alloc_user_space(sizeof(*map));
> - if (!access_ok(VERIFY_WRITE, map, sizeof(*map)))
> + if (!map)
> return -EFAULT;
> if (__put_user(idx, &map->offset))
> return -EFAULT;
> @@ -237,7 +237,7 @@ static int compat_drm_addmap(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> map = compat_alloc_user_space(sizeof(*map));
> - if (!access_ok(VERIFY_WRITE, map, sizeof(*map)))
> + if (!map)
> return -EFAULT;
> if (__put_user(m32.offset, &map->offset)
> || __put_user(m32.size, &map->size)
> @@ -277,7 +277,7 @@ static int compat_drm_rmmap(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> map = compat_alloc_user_space(sizeof(*map));
> - if (!access_ok(VERIFY_WRITE, map, sizeof(*map)))
> + if (!map)
> return -EFAULT;
> if (__put_user((void *)(unsigned long)handle, &map->handle))
> return -EFAULT;
> @@ -306,7 +306,7 @@ static int compat_drm_getclient(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> client = compat_alloc_user_space(sizeof(*client));
> - if (!access_ok(VERIFY_WRITE, client, sizeof(*client)))
> + if (!client)
> return -EFAULT;
> if (__put_user(idx, &client->idx))
> return -EFAULT;
> @@ -345,7 +345,7 @@ static int compat_drm_getstats(struct file *file, unsigned int cmd,
> int i, err;
>
> stats = compat_alloc_user_space(sizeof(*stats));
> - if (!access_ok(VERIFY_WRITE, stats, sizeof(*stats)))
> + if (!stats)
> return -EFAULT;
>
> err = drm_ioctl(file, DRM_IOCTL_GET_STATS, (unsigned long)stats);
> @@ -382,8 +382,7 @@ static int compat_drm_addbufs(struct file *file, unsigned int cmd,
> unsigned long agp_start;
>
> buf = compat_alloc_user_space(sizeof(*buf));
> - if (!access_ok(VERIFY_WRITE, buf, sizeof(*buf))
> - || !access_ok(VERIFY_WRITE, argp, sizeof(*argp)))
> + if (!buf || !access_ok(VERIFY_WRITE, argp, sizeof(*argp)))
> return -EFAULT;
>
> if (__copy_in_user(buf, argp, offsetof(drm_buf_desc32_t, agp_start))
> @@ -414,7 +413,7 @@ static int compat_drm_markbufs(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> buf = compat_alloc_user_space(sizeof(*buf));
> - if (!access_ok(VERIFY_WRITE, buf, sizeof(*buf)))
> + if (!buf)
> return -EFAULT;
>
> if (__put_user(b32.size, &buf->size)
> @@ -455,7 +454,7 @@ static int compat_drm_infobufs(struct file *file, unsigned int cmd,
>
> nbytes = sizeof(*request) + count * sizeof(struct drm_buf_desc);
> request = compat_alloc_user_space(nbytes);
> - if (!access_ok(VERIFY_WRITE, request, nbytes))
> + if (!request)
> return -EFAULT;
> list = (struct drm_buf_desc *) (request + 1);
>
> @@ -516,7 +515,7 @@ static int compat_drm_mapbufs(struct file *file, unsigned int cmd,
> return -EINVAL;
> nbytes = sizeof(*request) + count * sizeof(struct drm_buf_pub);
> request = compat_alloc_user_space(nbytes);
> - if (!access_ok(VERIFY_WRITE, request, nbytes))
> + if (!request)
> return -EFAULT;
> list = (struct drm_buf_pub *) (request + 1);
>
> @@ -563,7 +562,7 @@ static int compat_drm_freebufs(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request)))
> + if (!request)
> return -EFAULT;
> if (__put_user(req32.count, &request->count)
> || __put_user((int __user *)(unsigned long)req32.list,
> @@ -589,7 +588,7 @@ static int compat_drm_setsareactx(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request)))
> + if (!request)
> return -EFAULT;
> if (__put_user(req32.ctx_id, &request->ctx_id)
> || __put_user((void *)(unsigned long)req32.handle,
> @@ -613,7 +612,7 @@ static int compat_drm_getsareactx(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request)))
> + if (!request)
> return -EFAULT;
> if (__put_user(ctx_id, &request->ctx_id))
> return -EFAULT;
> @@ -646,7 +645,7 @@ static int compat_drm_resctx(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> res = compat_alloc_user_space(sizeof(*res));
> - if (!access_ok(VERIFY_WRITE, res, sizeof(*res)))
> + if (!res)
> return -EFAULT;
> if (__put_user(res32.count, &res->count)
> || __put_user((struct drm_ctx __user *) (unsigned long)res32.contexts,
> @@ -689,7 +688,7 @@ static int compat_drm_dma(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> d = compat_alloc_user_space(sizeof(*d));
> - if (!access_ok(VERIFY_WRITE, d, sizeof(*d)))
> + if (!d)
> return -EFAULT;
>
> if (__put_user(d32.context, &d->context)
> @@ -764,7 +763,7 @@ static int compat_drm_agp_info(struct file *file, unsigned int cmd,
> int err;
>
> info = compat_alloc_user_space(sizeof(*info));
> - if (!access_ok(VERIFY_WRITE, info, sizeof(*info)))
> + if (!info)
> return -EFAULT;
>
> err = drm_ioctl(file, DRM_IOCTL_AGP_INFO, (unsigned long)info);
> @@ -807,7 +806,7 @@ static int compat_drm_agp_alloc(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
> + if (!request
> || __put_user(req32.size, &request->size)
> || __put_user(req32.type, &request->type))
> return -EFAULT;
> @@ -834,7 +833,7 @@ static int compat_drm_agp_free(struct file *file, unsigned int cmd,
> u32 handle;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
> + if (!request
> || get_user(handle, &argp->handle)
> || __put_user(handle, &request->handle))
> return -EFAULT;
> @@ -858,7 +857,7 @@ static int compat_drm_agp_bind(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
> + if (!request
> || __put_user(req32.handle, &request->handle)
> || __put_user(req32.offset, &request->offset))
> return -EFAULT;
> @@ -874,7 +873,7 @@ static int compat_drm_agp_unbind(struct file *file, unsigned int cmd,
> u32 handle;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
> + if (!request
> || get_user(handle, &argp->handle)
> || __put_user(handle, &request->handle))
> return -EFAULT;
> @@ -897,8 +896,7 @@ static int compat_drm_sg_alloc(struct file *file, unsigned int cmd,
> unsigned long x;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
> - || !access_ok(VERIFY_WRITE, argp, sizeof(*argp))
> + if (!request || !access_ok(VERIFY_WRITE, argp, sizeof(*argp))
> || __get_user(x, &argp->size)
> || __put_user(x, &request->size))
> return -EFAULT;
> @@ -923,8 +921,7 @@ static int compat_drm_sg_free(struct file *file, unsigned int cmd,
> unsigned long x;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
> - || !access_ok(VERIFY_WRITE, argp, sizeof(*argp))
> + if (!request || !access_ok(VERIFY_WRITE, argp, sizeof(*argp))
> || __get_user(x, &argp->handle)
> || __put_user(x << PAGE_SHIFT, &request->handle))
> return -EFAULT;
> @@ -952,7 +949,7 @@ static int compat_drm_update_draw(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request)) ||
> + if (!request ||
> __put_user(update32.handle, &request->handle) ||
> __put_user(update32.type, &request->type) ||
> __put_user(update32.num, &request->num) ||
> @@ -994,7 +991,7 @@ static int compat_drm_wait_vblank(struct file *file, unsigned int cmd,
> return -EFAULT;
>
> request = compat_alloc_user_space(sizeof(*request));
> - if (!access_ok(VERIFY_WRITE, request, sizeof(*request))
> + if (!request
> || __put_user(req32.request.type, &request->request.type)
> || __put_user(req32.request.sequence, &request->request.sequence)
> || __put_user(req32.request.signal, &request->request.signal))
> --
> 2.1.4
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
--
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Next message: Geert Uytterhoeven: "[PATCH] kconfig: Wrap long "make help" text line for xenconfig"
Previous message: Dilger, Andreas: "Re: [lustre-devel] LIBCFS_ALLOC"
In reply to: Jarkko Sakkinen: "[PATCH v2] drm: remove redundant code form drm_ioc32.c"
Next in thread: Daniel Vetter: "Re: [PATCH v2] drm: remove redundant code form drm_ioc32.c"
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