From efed363752c07c5adeb99925b9765a0903178919 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 11 Feb 2021 12:42:58 -0700 Subject: [PATCH] qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit fca41af18e10318e4de090db47d9fa7169e1bf2f upstream. fw_cfg_showrev() is called by an indirect call in kobj_attr_show(), which violates clang's CFI checking because fw_cfg_showrev()'s second parameter is 'struct attribute', whereas the ->show() member of 'struct kobj_structure' expects the second parameter to be of type 'struct kobj_attribute'. $ cat /sys/firmware/qemu_fw_cfg/rev 3 $ dmesg | grep "CFI failure" [ 26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8): Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where this would have been caught automatically by the incompatible pointer types compiler warning. Update fw_cfg_showrev() accordingly. Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device") Link: https://github.com/ClangBuiltLinux/linux/issues/1299 Signed-off-by: Nathan Chancellor Reviewed-by: Sami Tolvanen Tested-by: Sedat Dilek Reviewed-by: Sami Tolvanen Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Kees Cook Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210211194258.4137998-1-nathan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/qemu_fw_cfg.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c index 6945c3c96637..59db70fb4561 100644 --- a/drivers/firmware/qemu_fw_cfg.c +++ b/drivers/firmware/qemu_fw_cfg.c @@ -296,15 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev) return 0; } -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf) +static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a, + char *buf) { return sprintf(buf, "%u\n", fw_cfg_rev); } -static const struct { - struct attribute attr; - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf); -} fw_cfg_rev_attr = { +static const struct kobj_attribute fw_cfg_rev_attr = { .attr = { .name = "rev", .mode = S_IRUSR }, .show = fw_cfg_showrev, };