From 7cc03e48965453b5df1cce5062c826189b04b960 Mon Sep 17 00:00:00 2001 From: Dmitry Skorodumov Date: Tue, 28 Jul 2015 18:38:32 +0400 Subject: [PATCH 1/2] x86/efi: Use all 64 bit of efi_memmap in setup_e820() The efi_info structure stores low 32 bits of memory map in efi_memmap and high 32 bits in efi_memmap_hi. While constructing pointer in the setup_e820(), need to take into account all 64 bit of the pointer. It is because on 64bit machine the function efi_get_memory_map() may return full 64bit pointer and before the patch that pointer was truncated. The issue is triggered on Parallles virtual machine and fixed with this patch. Signed-off-by: Dmitry Skorodumov Cc: Denis V. Lunev Cc: Signed-off-by: Matt Fleming --- arch/x86/boot/compressed/eboot.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index 2c82bd150d43..7d69afd8b6fa 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -1193,6 +1193,10 @@ static efi_status_t setup_e820(struct boot_params *params, unsigned int e820_type = 0; unsigned long m = efi->efi_memmap; +#ifdef CONFIG_X86_64 + m |= (u64)efi->efi_memmap_hi << 32; +#endif + d = (efi_memory_desc_t *)(m + (i * efi->efi_memdesc_size)); switch (d->type) { case EFI_RESERVED_TYPE: From 9115c7589b11349a1c3099758b4bded579ff69e0 Mon Sep 17 00:00:00 2001 From: Ricardo Neri Date: Wed, 15 Jul 2015 19:36:03 -0700 Subject: [PATCH 2/2] efi: Check for NULL efi kernel parameters Even though it is documented how to specifiy efi parameters, it is possible to cause a kernel panic due to a dereference of a NULL pointer when parsing such parameters if "efi" alone is given: PANIC: early exception 0e rip 10:ffffffff812fb361 error 0 cr2 0 [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.2.0-rc1+ #450 [ 0.000000] ffffffff81fe20a9 ffffffff81e03d50 ffffffff8184bb0f 00000000000003f8 [ 0.000000] 0000000000000000 ffffffff81e03e08 ffffffff81f371a1 64656c62616e6520 [ 0.000000] 0000000000000069 000000000000005f 0000000000000000 0000000000000000 [ 0.000000] Call Trace: [ 0.000000] [] dump_stack+0x45/0x57 [ 0.000000] [] early_idt_handler_common+0x81/0xae [ 0.000000] [] ? parse_option_str+0x11/0x90 [ 0.000000] [] arch_parse_efi_cmdline+0x15/0x42 [ 0.000000] [] do_early_param+0x50/0x8a [ 0.000000] [] parse_args+0x1e3/0x400 [ 0.000000] [] parse_early_options+0x24/0x28 [ 0.000000] [] ? loglevel+0x31/0x31 [ 0.000000] [] parse_early_param+0x31/0x3d [ 0.000000] [] setup_arch+0x2de/0xc08 [ 0.000000] [] ? vprintk_default+0x1a/0x20 [ 0.000000] [] start_kernel+0x90/0x423 [ 0.000000] [] x86_64_start_reservations+0x2a/0x2c [ 0.000000] [] x86_64_start_kernel+0xeb/0xef [ 0.000000] RIP 0xffffffff81ba2efc This panic is not reproducible with "efi=" as this will result in a non-NULL zero-length string. Thus, verify that the pointer to the parameter string is not NULL. This is consistent with other parameter-parsing functions which check for NULL pointers. Signed-off-by: Ricardo Neri Cc: Dave Young Cc: Signed-off-by: Matt Fleming --- arch/x86/platform/efi/efi.c | 5 +++++ drivers/firmware/efi/efi.c | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index cfba30f27392..e4308fe6afe8 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -972,6 +972,11 @@ u64 efi_mem_attributes(unsigned long phys_addr) static int __init arch_parse_efi_cmdline(char *str) { + if (!str) { + pr_warn("need at least one option\n"); + return -EINVAL; + } + if (parse_option_str(str, "old_map")) set_bit(EFI_OLD_MEMMAP, &efi.flags); if (parse_option_str(str, "debug")) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 9fa8084a7c8d..d6144e3b97c5 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -58,6 +58,11 @@ bool efi_runtime_disabled(void) static int __init parse_efi_cmdline(char *str) { + if (!str) { + pr_warn("need at least one option\n"); + return -EINVAL; + } + if (parse_option_str(str, "noruntime")) disable_runtime = true;