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authorLinus Torvalds <torvalds@linux-foundation.org>2021-08-15 06:38:26 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2021-08-15 06:38:26 -1000
commit12aef8acf0991e8a4a5fe892067e2c8fc6760ace (patch)
tree91d9d818664806cd6c1e7b7096d51434aa4d8404
parentb045b8cc865316062e520693ad6c8bac85aabece (diff)
parent55203550f9afb027389bd24ce85bd90044c3aa81 (diff)
Merge tag 'efi_urgent_for_v5.14_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull EFI fixes from Borislav Petkov: "A batch of fixes for the arm64 stub image loader: - fix a logic bug that can make the random page allocator fail spuriously - force reallocation of the Image when it overlaps with firmware reserved memory regions - fix an oversight that defeated on optimization introduced earlier where images loaded at a suitable offset are never moved if booting without randomization - complain about images that were not loaded at the right offset by the firmware image loader" * tag 'efi_urgent_for_v5.14_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: efi/libstub: arm64: Double check image alignment at entry efi/libstub: arm64: Warn when efi_random_alloc() fails efi/libstub: arm64: Relax 2M alignment again for relocatable kernels efi/libstub: arm64: Force Image reallocation if BSS was not reserved arm64: efi: kaslr: Fix occasional random alloc (and boot) failure
-rw-r--r--drivers/firmware/efi/libstub/arm64-stub.c71
-rw-r--r--drivers/firmware/efi/libstub/randomalloc.c2
2 files changed, 63 insertions, 10 deletions
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index 7bf0a7acae5e..2363fee9211c 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -35,15 +35,48 @@ efi_status_t check_platform_features(void)
}
/*
- * Although relocatable kernels can fix up the misalignment with respect to
- * MIN_KIMG_ALIGN, the resulting virtual text addresses are subtly out of
- * sync with those recorded in the vmlinux when kaslr is disabled but the
- * image required relocation anyway. Therefore retain 2M alignment unless
- * KASLR is in use.
+ * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail
+ * to provide space, and fail to zero it). Check for this condition by double
+ * checking that the first and the last byte of the image are covered by the
+ * same EFI memory map entry.
*/
-static u64 min_kimg_align(void)
+static bool check_image_region(u64 base, u64 size)
{
- return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;
+ unsigned long map_size, desc_size, buff_size;
+ efi_memory_desc_t *memory_map;
+ struct efi_boot_memmap map;
+ efi_status_t status;
+ bool ret = false;
+ int map_offset;
+
+ map.map = &memory_map;
+ map.map_size = &map_size;
+ map.desc_size = &desc_size;
+ map.desc_ver = NULL;
+ map.key_ptr = NULL;
+ map.buff_size = &buff_size;
+
+ status = efi_get_memory_map(&map);
+ if (status != EFI_SUCCESS)
+ return false;
+
+ for (map_offset = 0; map_offset < map_size; map_offset += desc_size) {
+ efi_memory_desc_t *md = (void *)memory_map + map_offset;
+ u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE;
+
+ /*
+ * Find the region that covers base, and return whether
+ * it covers base+size bytes.
+ */
+ if (base >= md->phys_addr && base < end) {
+ ret = (base + size) <= end;
+ break;
+ }
+ }
+
+ efi_bs_call(free_pool, memory_map);
+
+ return ret;
}
efi_status_t handle_kernel_image(unsigned long *image_addr,
@@ -56,6 +89,16 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
unsigned long kernel_size, kernel_memsize = 0;
u32 phys_seed = 0;
+ /*
+ * Although relocatable kernels can fix up the misalignment with
+ * respect to MIN_KIMG_ALIGN, the resulting virtual text addresses are
+ * subtly out of sync with those recorded in the vmlinux when kaslr is
+ * disabled but the image required relocation anyway. Therefore retain
+ * 2M alignment if KASLR was explicitly disabled, even if it was not
+ * going to be activated to begin with.
+ */
+ u64 min_kimg_align = efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;
+
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
if (!efi_nokaslr) {
status = efi_get_random_bytes(sizeof(phys_seed),
@@ -76,6 +119,10 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
if (image->image_base != _text)
efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n");
+ if (!IS_ALIGNED((u64)_text, EFI_KIMG_ALIGN))
+ efi_err("FIRMWARE BUG: kernel image not aligned on %ldk boundary\n",
+ EFI_KIMG_ALIGN >> 10);
+
kernel_size = _edata - _text;
kernel_memsize = kernel_size + (_end - _edata);
*reserve_size = kernel_memsize;
@@ -85,14 +132,18 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
* If KASLR is enabled, and we have some randomness available,
* locate the kernel at a randomized offset in physical memory.
*/
- status = efi_random_alloc(*reserve_size, min_kimg_align(),
+ status = efi_random_alloc(*reserve_size, min_kimg_align,
reserve_addr, phys_seed);
+ if (status != EFI_SUCCESS)
+ efi_warn("efi_random_alloc() failed: 0x%lx\n", status);
} else {
status = EFI_OUT_OF_RESOURCES;
}
if (status != EFI_SUCCESS) {
- if (IS_ALIGNED((u64)_text, min_kimg_align())) {
+ if (!check_image_region((u64)_text, kernel_memsize)) {
+ efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n");
+ } else if (IS_ALIGNED((u64)_text, min_kimg_align)) {
/*
* Just execute from wherever we were loaded by the
* UEFI PE/COFF loader if the alignment is suitable.
@@ -103,7 +154,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
}
status = efi_allocate_pages_aligned(*reserve_size, reserve_addr,
- ULONG_MAX, min_kimg_align());
+ ULONG_MAX, min_kimg_align);
if (status != EFI_SUCCESS) {
efi_err("Failed to relocate kernel\n");
diff --git a/drivers/firmware/efi/libstub/randomalloc.c b/drivers/firmware/efi/libstub/randomalloc.c
index a408df474d83..724155b9e10d 100644
--- a/drivers/firmware/efi/libstub/randomalloc.c
+++ b/drivers/firmware/efi/libstub/randomalloc.c
@@ -30,6 +30,8 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
region_end = min(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - 1,
(u64)ULONG_MAX);
+ if (region_end < size)
+ return 0;
first_slot = round_up(md->phys_addr, align);
last_slot = round_down(region_end - size + 1, align);