diff options
Diffstat (limited to '0001-efi-x86-Add-missing-error-handling-to-old_memmap-1-1.patch')
| -rw-r--r-- | 0001-efi-x86-Add-missing-error-handling-to-old_memmap-1-1.patch | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/0001-efi-x86-Add-missing-error-handling-to-old_memmap-1-1.patch b/0001-efi-x86-Add-missing-error-handling-to-old_memmap-1-1.patch new file mode 100644 index 000000000..8a773a84c --- /dev/null +++ b/0001-efi-x86-Add-missing-error-handling-to-old_memmap-1-1.patch @@ -0,0 +1,87 @@ +From 4e78921ba4dd0aca1cc89168f45039add4183f8e Mon Sep 17 00:00:00 2001 +From: Gen Zhang <blackgod016574@gmail.com> +Date: Sat, 25 May 2019 13:25:58 +0200 +Subject: [PATCH] efi/x86/Add missing error handling to old_memmap 1:1 mapping + code + +The old_memmap flow in efi_call_phys_prolog() performs numerous memory +allocations, and either does not check for failure at all, or it does +but fails to propagate it back to the caller, which may end up calling +into the firmware with an incomplete 1:1 mapping. + +So let's fix this by returning NULL from efi_call_phys_prolog() on +memory allocation failures only, and by handling this condition in the +caller. Also, clean up any half baked sets of page tables that we may +have created before returning with a NULL return value. + +Note that any failure at this level will trigger a panic() two levels +up, so none of this makes a huge difference, but it is a nice cleanup +nonetheless. + +[ardb: update commit log, add efi_call_phys_epilog() call on error path] + +Signed-off-by: Gen Zhang <blackgod016574@gmail.com> +Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> +Cc: Linus Torvalds <torvalds@linux-foundation.org> +Cc: Peter Zijlstra <peterz@infradead.org> +Cc: Rob Bradford <robert.bradford@intel.com> +Cc: Thomas Gleixner <tglx@linutronix.de> +Cc: linux-efi@vger.kernel.org +Link: http://lkml.kernel.org/r/20190525112559.7917-2-ard.biesheuvel@linaro.org +Signed-off-by: Ingo Molnar <mingo@kernel.org> +--- + arch/x86/platform/efi/efi.c | 2 ++ + arch/x86/platform/efi/efi_64.c | 9 ++++++--- + 2 files changed, 8 insertions(+), 3 deletions(-) + +diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c +index e1cb01a22fa8..a7189a3b4d70 100644 +--- a/arch/x86/platform/efi/efi.c ++++ b/arch/x86/platform/efi/efi.c +@@ -85,6 +85,8 @@ static efi_status_t __init phys_efi_set_virtual_address_map( + pgd_t *save_pgd; + + save_pgd = efi_call_phys_prolog(); ++ if (!save_pgd) ++ return EFI_ABORTED; + + /* Disable interrupts around EFI calls: */ + local_irq_save(flags); +diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c +index cf0347f61b21..08ce8177c3af 100644 +--- a/arch/x86/platform/efi/efi_64.c ++++ b/arch/x86/platform/efi/efi_64.c +@@ -84,13 +84,15 @@ pgd_t * __init efi_call_phys_prolog(void) + + if (!efi_enabled(EFI_OLD_MEMMAP)) { + efi_switch_mm(&efi_mm); +- return NULL; ++ return efi_mm.pgd; + } + + early_code_mapping_set_exec(1); + + n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE); + save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL); ++ if (!save_pgd) ++ return NULL; + + /* + * Build 1:1 identity mapping for efi=old_map usage. Note that +@@ -138,10 +140,11 @@ pgd_t * __init efi_call_phys_prolog(void) + pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX; + } + +-out: + __flush_tlb_all(); +- + return save_pgd; ++out: ++ efi_call_phys_epilog(save_pgd); ++ return NULL; + } + + void __init efi_call_phys_epilog(pgd_t *save_pgd) +-- +2.21.0 + |