From a2f1482fc0e6c5dbdbafecd360d168f9c12fc529 Mon Sep 17 00:00:00 2001 From: Ilias Apalodimas Date: Mon, 3 Jan 2022 14:07:37 +0200 Subject: efi_loader: Get rid of kaslr-seed if EFI_RNG_PROTOCOL is installed U-Boot, in some occasions, injects a 'kaslr-seed' property on the /chosen node. That would be problematic in case we want to measure the DTB we install in the configuration table, since it would change across reboots. The Linux kernel EFI-stub completely ignores it and only relies on EFI_RNG_PROTOCOL for it's own randomness needs (i.e the randomization of the physical placement of the kernel). In fact it (blindly) overwrites the existing seed if the protocol is installed. However it still uses it for randomizing it's virtual placement. So let's get rid of it in the presence of the RNG protocol. It's worth noting that TPMs also provide an RNG. So if we tweak our EFI_RNG_PROTOCOL slightly and install the protocol when a TPM device is present the 'kaslr-seed' property will always be removed, allowing us to reliably measure our DTB. Acked-by: Ard Biesheuvel Signed-off-by: Ilias Apalodimas Reviewed-by: Mark Kettenis --- lib/efi_loader/efi_dt_fixup.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'lib') diff --git a/lib/efi_loader/efi_dt_fixup.c b/lib/efi_loader/efi_dt_fixup.c index b6fe5d2e5a3..d3923e5dba1 100644 --- a/lib/efi_loader/efi_dt_fixup.c +++ b/lib/efi_loader/efi_dt_fixup.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -40,6 +41,38 @@ static void efi_reserve_memory(u64 addr, u64 size, bool nomap) addr, size); } +/** + * efi_try_purge_kaslr_seed() - Remove unused kaslr-seed + * + * Kernel's EFI STUB only relies on EFI_RNG_PROTOCOL for randomization + * and completely ignores the kaslr-seed for its own randomness needs + * (i.e the randomization of the physical placement of the kernel). + * Weed it out from the DTB we hand over, which would mess up our DTB + * TPM measurements as well. + * + * @fdt: Pointer to device tree + */ +void efi_try_purge_kaslr_seed(void *fdt) +{ + const efi_guid_t efi_guid_rng_protocol = EFI_RNG_PROTOCOL_GUID; + struct efi_handler *handler; + efi_status_t ret; + int nodeoff = 0; + int err = 0; + + ret = efi_search_protocol(efi_root, &efi_guid_rng_protocol, &handler); + if (ret != EFI_SUCCESS) + return; + + nodeoff = fdt_path_offset(fdt, "/chosen"); + if (nodeoff < 0) + return; + + err = fdt_delprop(fdt, nodeoff, "kaslr-seed"); + if (err < 0 && err != -FDT_ERR_NOTFOUND) + log_err("Error deleting kaslr-seed\n"); +} + /** * efi_carve_out_dt_rsv() - Carve out DT reserved memory ranges * -- cgit v1.2.3 From 717b33cb9b51ec70a3795783eaf02836bfa9b098 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Sat, 15 Jan 2022 02:11:22 +0100 Subject: efidebug: avoid 'dfu_alt_info not defined' message If variable dfu_alt_info is not defined duplicate messages are displayed. => efidebug boot dump Scanning disk mmc2.blk... Scanning disk mmc1.blk... Scanning disk mmc0.blk... Found 3 disks No EFI system partition "dfu_alt_info" env variable not defined! Probably dfu_alt_info not defined "dfu_alt_info" env variable not defined! Probably dfu_alt_info not defined Remove the 'Probably dfu_alt_info not defined' message. Instead write a warning if the variable contains no entities. Signed-off-by: Heinrich Schuchardt --- lib/efi_loader/efi_firmware.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c index a1b88dbfc28..519a47267ca 100644 --- a/lib/efi_loader/efi_firmware.c +++ b/lib/efi_loader/efi_firmware.c @@ -128,8 +128,11 @@ static efi_status_t efi_get_dfu_info( size_t names_len, total_size; int dfu_num, i; u16 *name, *next; + int ret; - dfu_init_env_entities(NULL, NULL); + ret = dfu_init_env_entities(NULL, NULL); + if (ret) + return EFI_SUCCESS; names_len = 0; dfu_num = 0; @@ -138,7 +141,7 @@ static efi_status_t efi_get_dfu_info( dfu_num++; } if (!dfu_num) { - log_warning("Probably dfu_alt_info not defined\n"); + log_warning("No entities in dfu_alt_info\n"); *image_info_size = 0; dfu_free_entities(); -- cgit v1.2.3 From 866e2ac5aa4b8a36db5bb4afd8b4e8302029849a Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Tue, 4 Jan 2022 03:51:10 -0700 Subject: efi: Move exit_boot_services into a function At present this code is inline in the app and stub. But they do the same thing. The difference is that the stub does it immediately and the app doesn't want to do it until the end (when it boots a kernel) or not at all, if returning to UEFI. Move it into a function so it can be called as needed. Add a comment showing how to store the memory map so that it can be accessed within the app if needed, for debugging purposes only. The map can change without notice. Signed-off-by: Simon Glass --- lib/efi/efi.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ lib/efi/efi_app.c | 9 +++++++ lib/efi/efi_stub.c | 66 +++++++++---------------------------------------- 3 files changed, 92 insertions(+), 55 deletions(-) (limited to 'lib') diff --git a/lib/efi/efi.c b/lib/efi/efi.c index cd6bf47b180..aa42f1842f3 100644 --- a/lib/efi/efi.c +++ b/lib/efi/efi.c @@ -135,3 +135,75 @@ void efi_free(struct efi_priv *priv, void *ptr) boot->free_pool(ptr); } + +int efi_store_memory_map(struct efi_priv *priv) +{ + struct efi_boot_services *boot = priv->sys_table->boottime; + efi_uintn_t size, desc_size; + efi_status_t ret; + + /* Get the memory map so we can switch off EFI */ + size = 0; + ret = boot->get_memory_map(&size, NULL, &priv->memmap_key, + &priv->memmap_desc_size, + &priv->memmap_version); + if (ret != EFI_BUFFER_TOO_SMALL) { + /* + * Note this function avoids using printf() since it is not + * available in the stub + */ + printhex2(EFI_BITS_PER_LONG); + putc(' '); + printhex2(ret); + puts(" No memory map\n"); + return ret; + } + /* + * Since doing a malloc() may change the memory map and also we want to + * be able to read the memory map in efi_call_exit_boot_services() + * below, after more changes have happened + */ + priv->memmap_alloc = size + 1024; + priv->memmap_size = priv->memmap_alloc; + priv->memmap_desc = efi_malloc(priv, size, &ret); + if (!priv->memmap_desc) { + printhex2(ret); + puts(" No memory for memory descriptor\n"); + return ret; + } + + ret = boot->get_memory_map(&priv->memmap_size, priv->memmap_desc, + &priv->memmap_key, &desc_size, + &priv->memmap_version); + if (ret) { + printhex2(ret); + puts(" Can't get memory map\n"); + return ret; + } + + return 0; +} + +int efi_call_exit_boot_services(void) +{ + struct efi_priv *priv = efi_get_priv(); + const struct efi_boot_services *boot = priv->boot; + efi_uintn_t size; + u32 version; + efi_status_t ret; + + size = priv->memmap_alloc; + ret = boot->get_memory_map(&size, priv->memmap_desc, + &priv->memmap_key, + &priv->memmap_desc_size, &version); + if (ret) { + printhex2(ret); + puts(" Can't get memory map\n"); + return ret; + } + ret = boot->exit_boot_services(priv->parent_image, priv->memmap_key); + if (ret) + return ret; + + return 0; +} diff --git a/lib/efi/efi_app.c b/lib/efi/efi_app.c index d60f2f6c28f..5c2593bc4d9 100644 --- a/lib/efi/efi_app.c +++ b/lib/efi/efi_app.c @@ -321,6 +321,15 @@ efi_status_t EFIAPI efi_main(efi_handle_t image, return ret; } + /* + * We could store the EFI memory map here, but it changes all the time, + * so this is only useful for debugging. + * + * ret = efi_store_memory_map(priv); + * if (ret) + * return ret; + */ + printf("starting\n"); board_init_f(GD_FLG_SKIP_RELOC); diff --git a/lib/efi/efi_stub.c b/lib/efi/efi_stub.c index c89ae7c9072..646cde3214c 100644 --- a/lib/efi/efi_stub.c +++ b/lib/efi/efi_stub.c @@ -304,15 +304,12 @@ efi_status_t EFIAPI efi_main(efi_handle_t image, { struct efi_priv local_priv, *priv = &local_priv; struct efi_boot_services *boot = sys_table->boottime; - struct efi_mem_desc *desc; struct efi_entry_memmap map; struct efi_gop *gop; struct efi_entry_gopmode mode; struct efi_entry_systable table; efi_guid_t efi_gop_guid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID; - efi_uintn_t key, desc_size, size; efi_status_t ret; - u32 version; int cs32; ret = efi_init(priv, "Payload", image, sys_table); @@ -327,24 +324,11 @@ efi_status_t EFIAPI efi_main(efi_handle_t image, if (cs32 < 0) return EFI_UNSUPPORTED; - /* Get the memory map so we can switch off EFI */ - size = 0; - ret = boot->get_memory_map(&size, NULL, &key, &desc_size, &version); - if (ret != EFI_BUFFER_TOO_SMALL) { - printhex2(EFI_BITS_PER_LONG); - putc(' '); - printhex2(ret); - puts(" No memory map\n"); - return ret; - } - size += 1024; /* Since doing a malloc() may change the memory map! */ - desc = efi_malloc(priv, size, &ret); - if (!desc) { - printhex2(ret); - puts(" No memory for memory descriptor\n"); + ret = efi_store_memory_map(priv); + if (ret) return ret; - } - ret = setup_info_table(priv, size + 128); + + ret = setup_info_table(priv, priv->memmap_size + 128); if (ret) return ret; @@ -360,48 +344,20 @@ efi_status_t EFIAPI efi_main(efi_handle_t image, sizeof(struct efi_gop_mode_info)); } - ret = boot->get_memory_map(&size, desc, &key, &desc_size, &version); - if (ret) { - printhex2(ret); - puts(" Can't get memory map\n"); - return ret; - } - table.sys_table = (ulong)sys_table; add_entry_addr(priv, EFIET_SYS_TABLE, &table, sizeof(table), NULL, 0); - ret = boot->exit_boot_services(image, key); - if (ret) { - /* - * Unfortunately it happens that we cannot exit boot services - * the first time. But the second time it work. I don't know - * why but this seems to be a repeatable problem. To get - * around it, just try again. - */ - printhex2(ret); - puts(" Can't exit boot services\n"); - size = sizeof(desc); - ret = boot->get_memory_map(&size, desc, &key, &desc_size, - &version); - if (ret) { - printhex2(ret); - puts(" Can't get memory map\n"); - return ret; - } - ret = boot->exit_boot_services(image, key); - if (ret) { - printhex2(ret); - puts(" Can't exit boot services 2\n"); - return ret; - } - } + ret = efi_call_exit_boot_services(); + if (ret) + return ret; /* The EFI UART won't work now, switch to a debug one */ use_uart = true; - map.version = version; - map.desc_size = desc_size; - add_entry_addr(priv, EFIET_MEMORY_MAP, &map, sizeof(map), desc, size); + map.version = priv->memmap_version; + map.desc_size = priv->memmap_desc_size; + add_entry_addr(priv, EFIET_MEMORY_MAP, &map, sizeof(map), + priv->memmap_desc, priv->memmap_size); add_entry_addr(priv, EFIET_END, NULL, 0, 0, 0); memcpy((void *)CONFIG_SYS_TEXT_BASE, _binary_u_boot_bin_start, -- cgit v1.2.3 From 25a326b0066b3c449a0a91889b0ce19cb7320237 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Tue, 4 Jan 2022 03:51:12 -0700 Subject: efi: Support the efi command in the app At present the 'efi' command only works in the EFI payload. Update it to work in the app too, so the memory map can be examined. Signed-off-by: Simon Glass Signed-off-by: Heinrich Schuchardt --- lib/efi/efi_app.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'lib') diff --git a/lib/efi/efi_app.c b/lib/efi/efi_app.c index 5c2593bc4d9..6980933d7ea 100644 --- a/lib/efi/efi_app.c +++ b/lib/efi/efi_app.c @@ -32,6 +32,39 @@ int efi_info_get(enum efi_entry_t type, void **datap, int *sizep) return -ENOSYS; } +int efi_get_mmap(struct efi_mem_desc **descp, int *sizep, uint *keyp, + int *desc_sizep, uint *versionp) +{ + struct efi_priv *priv = efi_get_priv(); + struct efi_boot_services *boot = priv->sys_table->boottime; + efi_uintn_t size, desc_size, key; + struct efi_mem_desc *desc; + efi_status_t ret; + u32 version; + + /* Get the memory map so we can switch off EFI */ + size = 0; + ret = boot->get_memory_map(&size, NULL, &key, &desc_size, &version); + if (ret != EFI_BUFFER_TOO_SMALL) + return log_msg_ret("get", -ENOMEM); + + desc = malloc(size); + if (!desc) + return log_msg_ret("mem", -ENOMEM); + + ret = boot->get_memory_map(&size, desc, &key, &desc_size, &version); + if (ret) + return log_msg_ret("get", -EINVAL); + + *descp = desc; + *sizep = size; + *desc_sizep = desc_size; + *versionp = version; + *keyp = key; + + return 0; +} + /** * efi_bind_block() - bind a new block device to an EFI device * -- cgit v1.2.3