4.4-stable review patch. If anyone has any objections, please let me know.
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From: Greg Kroah-Hartman gregkh@linuxfoundation.org
commit af97a77bc01ce49a466f9d4c0125479e2e2230b6 upstream.
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 torvalds@linux-foundation.org Tested-by: Dave Young dyoung@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org Cc: H. Peter Anvin hpa@zytor.com Cc: Matt Fleming matt@codeblueprint.co.uk Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20171206095010.24170-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/firmware/efi/efi.c | 3 +-- drivers/firmware/efi/esrt.c | 15 ++++++--------- drivers/firmware/efi/runtime-map.c | 10 +++++----- include/linux/sysfs.h | 6 ++++++ 4 files changed, 18 insertions(+), 16 deletions(-)
--- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -113,8 +113,7 @@ 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 @@ -105,7 +105,7 @@ 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;
@@ -116,18 +116,16 @@ 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"); @@ -195,14 +193,13 @@ 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 @@ -67,11 +67,11 @@ 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 @@ -116,6 +116,12 @@ struct attribute_group { .show = _name##_show, \ }
+#define __ATTR_RO_MODE(_name, _mode) { \ + .attr = { .name = __stringify(_name), \ + .mode = VERIFY_OCTAL_PERMISSIONS(_mode) }, \ + .show = _name##_show, \ +} + #define __ATTR_WO(_name) { \ .attr = { .name = __stringify(_name), .mode = S_IWUSR }, \ .store = _name##_store, \