On Wed, 01 Jul 2015, Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx> > --- > 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. 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@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
