| Message ID | 20200608153523.72548-2-benjamin.romer@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | CVE-2019-12380 | expand |
On 08.06.20 17:35, Benjamin M Romer wrote: > From: Gen Zhang <blackgod016574@gmail.com> > > 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> > > (cherry picked from commit 4e78921ba4dd0aca1cc89168f45039add4183f8e) > CVE-2019-12380 > [ ben_r: adjusted patch for context, modified error handling around > EFI_OLD_MAPPING to fit CR3 handling in this timeline. ] > Signed-off-by: Benjamin M Romer <benjamin.romer@canonical.com> Acked-by: Stefan Bader <stefan.bader@canonical.com> > --- You describe quite some adaptions above. In this case this should be backported from and not cherry picked. But this can be done when applying. -Stefan > arch/x86/platform/efi/efi.c | 2 ++ > arch/x86/platform/efi/efi_64.c | 9 +++++++-- > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c > index e7f19dec16b9..b12991563074 100644 > --- a/arch/x86/platform/efi/efi.c > +++ b/arch/x86/platform/efi/efi.c > @@ -86,6 +86,8 @@ 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 19231f716580..f83c6f6dcad9 100644 > --- a/arch/x86/platform/efi/efi_64.c > +++ b/arch/x86/platform/efi/efi_64.c > @@ -84,13 +84,16 @@ pgd_t * __init efi_call_phys_prolog(void) > if (!efi_enabled(EFI_OLD_MEMMAP)) { > save_pgd = (pgd_t *)__read_cr3(); > write_cr3((unsigned long)efi_scratch.efi_pgt); > - goto out; > + __flush_tlb_all(); > + return save_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 +141,12 @@ 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) >
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index e7f19dec16b9..b12991563074 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -86,6 +86,8 @@ 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 19231f716580..f83c6f6dcad9 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -84,13 +84,16 @@ pgd_t * __init efi_call_phys_prolog(void) if (!efi_enabled(EFI_OLD_MEMMAP)) { save_pgd = (pgd_t *)__read_cr3(); write_cr3((unsigned long)efi_scratch.efi_pgt); - goto out; + __flush_tlb_all(); + return save_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 +141,12 @@ 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)