From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: [PATCH] efi: move some sysfs files to be read-only by root Date: Tue, 5 Dec 2017 11:13:43 +0100 Message-ID: <20171205101343.GA5416@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: Matt Fleming , Ard Biesheuvel Cc: Dave Young , Linus Torvalds , "Tobin C. Harding" , LKML , "linux-efi@vger.kernel.org" List-Id: linux-efi@vger.kernel.org Thanks to the scripts/leaking_addresses.pl script, it was found that some EFI values should not be readable by non-root users. So make them root-only, and to do that, add a __ATTR_RO_MODE() macro to make this easier, and use it in other places at the same time. Reported-by: Linus Torvalds Tested-by: Dave Young Cc: Matt Fleming Cc: Ard Biesheuvel Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/efi/efi.c | 3 +-- drivers/firmware/efi/esrt.c | 15 ++++++--------- drivers/firmware/efi/runtime-map.c | 10 +++++----- include/linux/sysfs.h | 5 +++++ 4 files changed, 17 insertions(+), 16 deletions(-) --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -143,8 +143,7 @@ static ssize_t systab_show(struct kobjec return str - buf; } -static struct kobj_attribute efi_attr_systab = - __ATTR(systab, 0400, systab_show, NULL); +static struct kobj_attribute efi_attr_systab = __ATTR_RO_MODE(systab, 0400); #define EFI_FIELD(var) efi.var --- a/drivers/firmware/efi/esrt.c +++ b/drivers/firmware/efi/esrt.c @@ -106,7 +106,7 @@ static const struct sysfs_ops esre_attr_ }; /* Generic ESRT Entry ("ESRE") support. */ -static ssize_t esre_fw_class_show(struct esre_entry *entry, char *buf) +static ssize_t fw_class_show(struct esre_entry *entry, char *buf) { char *str = buf; @@ -117,18 +117,16 @@ static ssize_t esre_fw_class_show(struct return str - buf; } -static struct esre_attribute esre_fw_class = __ATTR(fw_class, 0400, - esre_fw_class_show, NULL); +static struct esre_attribute esre_fw_class = __ATTR_RO_MODE(fw_class, 0400); #define esre_attr_decl(name, size, fmt) \ -static ssize_t esre_##name##_show(struct esre_entry *entry, char *buf) \ +static ssize_t name##_show(struct esre_entry *entry, char *buf) \ { \ return sprintf(buf, fmt "\n", \ le##size##_to_cpu(entry->esre.esre1->name)); \ } \ \ -static struct esre_attribute esre_##name = __ATTR(name, 0400, \ - esre_##name##_show, NULL) +static struct esre_attribute esre_##name = __ATTR_RO_MODE(name, 0400) esre_attr_decl(fw_type, 32, "%u"); esre_attr_decl(fw_version, 32, "%u"); @@ -193,14 +191,13 @@ static int esre_create_sysfs_entry(void /* support for displaying ESRT fields at the top level */ #define esrt_attr_decl(name, size, fmt) \ -static ssize_t esrt_##name##_show(struct kobject *kobj, \ +static ssize_t name##_show(struct kobject *kobj, \ struct kobj_attribute *attr, char *buf)\ { \ return sprintf(buf, fmt "\n", le##size##_to_cpu(esrt->name)); \ } \ \ -static struct kobj_attribute esrt_##name = __ATTR(name, 0400, \ - esrt_##name##_show, NULL) +static struct kobj_attribute esrt_##name = __ATTR_RO_MODE(name, 0400) esrt_attr_decl(fw_resource_count, 32, "%u"); esrt_attr_decl(fw_resource_count_max, 32, "%u"); --- a/drivers/firmware/efi/runtime-map.c +++ b/drivers/firmware/efi/runtime-map.c @@ -63,11 +63,11 @@ static ssize_t map_attr_show(struct kobj return map_attr->show(entry, buf); } -static struct map_attribute map_type_attr = __ATTR_RO(type); -static struct map_attribute map_phys_addr_attr = __ATTR_RO(phys_addr); -static struct map_attribute map_virt_addr_attr = __ATTR_RO(virt_addr); -static struct map_attribute map_num_pages_attr = __ATTR_RO(num_pages); -static struct map_attribute map_attribute_attr = __ATTR_RO(attribute); +static struct map_attribute map_type_attr = __ATTR_RO_MODE(type, 0400); +static struct map_attribute map_phys_addr_attr = __ATTR_RO_MODE(phys_addr, 0400); +static struct map_attribute map_virt_addr_attr = __ATTR_RO_MODE(virt_addr, 0400); +static struct map_attribute map_num_pages_attr = __ATTR_RO_MODE(num_pages, 0400); +static struct map_attribute map_attribute_attr = __ATTR_RO_MODE(attribute, 0400); /* * These are default attributes that are added for every memmap entry. --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -117,6 +117,11 @@ struct attribute_group { .show = _name##_show, \ } +#define __ATTR_RO_MODE(_name, _mode) { \ + .attr = { .name = __stringify(_name), .mode = _mode }, \ + .show = _name##_show, \ +} + #define __ATTR_WO(_name) { \ .attr = { .name = __stringify(_name), .mode = S_IWUSR }, \ .store = _name##_store, \