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Message-Id: <20170903120757.14968-28-ard.biesheuvel@linaro.org>
Date: Sun, 3 Sep 2017 13:07:55 +0100
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: linux-arm-kernel@...ts.infradead.org,
kernel-hardening@...ts.openwall.com
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Arnd Bergmann <arnd@...db.de>,
Nicolas Pitre <nico@...aro.org>,
Russell King <linux@...linux.org.uk>,
Kees Cook <keescook@...omium.org>,
Thomas Garnier <thgarnie@...gle.com>,
Marc Zyngier <marc.zyngier@....com>,
Mark Rutland <mark.rutland@....com>,
Tony Lindgren <tony@...mide.com>,
Matt Fleming <matt@...eblueprint.co.uk>,
Dave Martin <dave.martin@....com>
Subject: [PATCH v2 27/29] efi/libstub: add 'max' parameter to efi_random_alloc()
Add an upper limit to efi_random_alloc() so we can use it to randomly
allocate the ARM kernel in lowmem.
Cc: Matt Fleming <matt@...eblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
---
drivers/firmware/efi/libstub/arm64-stub.c | 2 +-
drivers/firmware/efi/libstub/efistub.h | 3 ++-
drivers/firmware/efi/libstub/random.c | 11 +++++++----
3 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index b4c2589d7c91..940766f90adb 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -94,7 +94,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg,
*reserve_size = kernel_memsize + offset;
status = efi_random_alloc(sys_table_arg, *reserve_size,
MIN_KIMG_ALIGN, reserve_addr,
- (u32)phys_seed);
+ (u32)phys_seed, ULONG_MAX);
*image_addr = *reserve_addr + offset;
} else {
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 83f268c05007..3a670a5f759f 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -60,7 +60,8 @@ efi_status_t efi_get_random_bytes(efi_system_table_t *sys_table,
efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg,
unsigned long size, unsigned long align,
- unsigned long *addr, unsigned long random_seed);
+ unsigned long *addr, unsigned long random_seed,
+ unsigned long max);
efi_status_t check_platform_features(efi_system_table_t *sys_table_arg);
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c
index 7e72954d5860..810e60e76211 100644
--- a/drivers/firmware/efi/libstub/random.c
+++ b/drivers/firmware/efi/libstub/random.c
@@ -42,7 +42,8 @@ efi_status_t efi_get_random_bytes(efi_system_table_t *sys_table_arg,
*/
static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
unsigned long size,
- unsigned long align_shift)
+ unsigned long align_shift,
+ unsigned long max)
{
unsigned long align = 1UL << align_shift;
u64 first_slot, last_slot, region_end;
@@ -50,7 +51,8 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
if (md->type != EFI_CONVENTIONAL_MEMORY)
return 0;
- region_end = min((u64)ULONG_MAX, md->phys_addr + md->num_pages*EFI_PAGE_SIZE - 1);
+ region_end = min_t(u64, max, md->phys_addr +
+ md->num_pages * EFI_PAGE_SIZE - 1);
first_slot = round_up(md->phys_addr, align);
last_slot = round_down(region_end - size + 1, align);
@@ -73,7 +75,8 @@ efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg,
unsigned long size,
unsigned long align,
unsigned long *addr,
- unsigned long random_seed)
+ unsigned long random_seed,
+ unsigned long max)
{
unsigned long map_size, desc_size, total_slots = 0, target_slot;
unsigned long buff_size;
@@ -101,7 +104,7 @@ efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg,
efi_memory_desc_t *md = (void *)memory_map + map_offset;
unsigned long slots;
- slots = get_entry_num_slots(md, size, ilog2(align));
+ slots = get_entry_num_slots(md, size, ilog2(align), max);
MD_NUM_SLOTS(md) = slots;
total_slots += slots;
}
--
2.11.0
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