From 20b1e22d01a4b0b11d3a1066e9feb04be38607ec Mon Sep 17 00:00:00 2001 From: Nicolai Stange Date: Thu, 5 Jan 2017 13:51:29 +0100 Subject: x86/efi: Don't allocate memmap through memblock after mm_init() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With the following commit: 4bc9f92e64c8 ("x86/efi-bgrt: Use efi_mem_reserve() to avoid copying image data") ... efi_bgrt_init() calls into the memblock allocator through efi_mem_reserve() => efi_arch_mem_reserve() *after* mm_init() has been called. Indeed, KASAN reports a bad read access later on in efi_free_boot_services(): BUG: KASAN: use-after-free in efi_free_boot_services+0xae/0x24c at addr ffff88022de12740 Read of size 4 by task swapper/0/0 page:ffffea0008b78480 count:0 mapcount:-127 mapping: (null) index:0x1 flags: 0x5fff8000000000() [...] Call Trace: dump_stack+0x68/0x9f kasan_report_error+0x4c8/0x500 kasan_report+0x58/0x60 __asan_load4+0x61/0x80 efi_free_boot_services+0xae/0x24c start_kernel+0x527/0x562 x86_64_start_reservations+0x24/0x26 x86_64_start_kernel+0x157/0x17a start_cpu+0x5/0x14 The instruction at the given address is the first read from the memmap's memory, i.e. the read of md->type in efi_free_boot_services(). Note that the writes earlier in efi_arch_mem_reserve() don't splat because they're done through early_memremap()ed addresses. So, after memblock is gone, allocations should be done through the "normal" page allocator. Introduce a helper, efi_memmap_alloc() for this. Use it from efi_arch_mem_reserve(), efi_free_boot_services() and, for the sake of consistency, from efi_fake_memmap() as well. Note that for the latter, the memmap allocations cease to be page aligned. This isn't needed though. Tested-by: Dan Williams Signed-off-by: Nicolai Stange Reviewed-by: Ard Biesheuvel Cc: # v4.9 Cc: Dave Young Cc: Linus Torvalds Cc: Matt Fleming Cc: Mika Penttilä Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Fixes: 4bc9f92e64c8 ("x86/efi-bgrt: Use efi_mem_reserve() to avoid copying image data") Link: http://lkml.kernel.org/r/20170105125130.2815-1-nicstange@gmail.com Signed-off-by: Ingo Molnar --- include/linux/efi.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/efi.h b/include/linux/efi.h index a07a476178cd..0c5420208c40 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -950,6 +950,7 @@ static inline efi_status_t efi_query_variable_store(u32 attributes, #endif extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr); +extern phys_addr_t __init efi_memmap_alloc(unsigned int num_entries); extern int __init efi_memmap_init_early(struct efi_memory_map_data *data); extern int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size); extern void __init efi_memmap_unmap(void); -- cgit v1.2.3 From 0100a3e67a9cef64d72cd3a1da86f3ddbee50363 Mon Sep 17 00:00:00 2001 From: Peter Jones Date: Mon, 12 Dec 2016 18:42:28 -0500 Subject: efi/x86: Prune invalid memory map entries and fix boot regression Some machines, such as the Lenovo ThinkPad W541 with firmware GNET80WW (2.28), include memory map entries with phys_addr=0x0 and num_pages=0. These machines fail to boot after the following commit, commit 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()") Fix this by removing such bogus entries from the memory map. Furthermore, currently the log output for this case (with efi=debug) looks like: [ 0.000000] efi: mem45: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0xffffffffffffffff] (0MB) This is clearly wrong, and also not as informative as it could be. This patch changes it so that if we find obviously invalid memory map entries, we print an error and skip those entries. It also detects the display of the address range calculation overflow, so the new output is: [ 0.000000] efi: [Firmware Bug]: Invalid EFI memory map entries: [ 0.000000] efi: mem45: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0x0000000000000000] (invalid) It also detects memory map sizes that would overflow the physical address, for example phys_addr=0xfffffffffffff000 and num_pages=0x0200000000000001, and prints: [ 0.000000] efi: [Firmware Bug]: Invalid EFI memory map entries: [ 0.000000] efi: mem45: [Reserved | | | | | | | | | | | | ] range=[phys_addr=0xfffffffffffff000-0x20ffffffffffffffff] (invalid) It then removes these entries from the memory map. Signed-off-by: Peter Jones Signed-off-by: Ard Biesheuvel [ardb: refactor for clarity with no functional changes, avoid PAGE_SHIFT] Signed-off-by: Matt Fleming [Matt: Include bugzilla info in commit log] Cc: # v4.9+ Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://bugzilla.kernel.org/show_bug.cgi?id=191121 Signed-off-by: Ingo Molnar --- include/linux/efi.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/efi.h b/include/linux/efi.h index 0c5420208c40..5b1af30ece55 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -103,6 +103,7 @@ typedef struct { #define EFI_PAGE_SHIFT 12 #define EFI_PAGE_SIZE (1UL << EFI_PAGE_SHIFT) +#define EFI_PAGES_MAX (U64_MAX >> EFI_PAGE_SHIFT) typedef struct { u32 type; -- cgit v1.2.3