On 07/02/2015 11:10 AM, Jani Nikula wrote: > On Wed, 01 Jul 2015, Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com> > 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. >> >> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com> >> --- >> 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..77b63e7 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 || !argp) > The risks of touching old code... who does access_ok on argp now? That > doesn't come from compat_alloc_user_space. > > Same pattern repeated below a few times. Right. Thanks and sorry about sloppiness. I'll update the patch.
> > BR, > Jani. > > >> 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 || !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 || !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 at lists.freedesktop.org >> http://lists.freedesktop.org/mailman/listinfo/dri-devel /Jarkko
