On 24/04/13 15:54, Josh Boyer wrote: > On Wed, Apr 24, 2013 at 03:44:30PM +0100, Matt Fleming wrote: >> On 24/04/13 15:37, Josh Boyer wrote: >>> We need to check the runtime sys_table for the EFI version the firmware >>> specifies instead of just checking for a NULL QueryVariableInfo. Older >>> implementations of EFI don't have QueryVariableInfo but the runtime is >>> a smaller structure, so the pointer to it may be pointing off into garbage. >>> >>> This is apparently the case with several Apple firmwares that support EFI >>> 1.10, and the current check causes them to no longer boot. Fix based on >>> a suggestion from Matthew Garrett. >>> >>> Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxx> >>> --- >>> arch/x86/boot/compressed/eboot.c | 4 +++- >>> 1 file changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c >>> index 8615f75..b46efbf 100644 >>> --- a/arch/x86/boot/compressed/eboot.c >>> +++ b/arch/x86/boot/compressed/eboot.c >>> @@ -258,7 +258,9 @@ static efi_status_t setup_efi_vars(struct boot_params *params) >>> u64 store_size, remaining_size, var_size; >>> efi_status_t status; >>> >>> - if (!sys_table->runtime->query_variable_info) >>> + if (sys_table->runtime->hdr.revision < EFI_2_00_SYSTEM_TABLE_REVISION) >>> + return EFI_UNSUPPORTED; >>> + else if(!sys_table->runtime->query_variable_info) >>> return EFI_UNSUPPORTED; >>> >>> data = (struct setup_data *)(unsigned long)params->hdr.setup_data; >>> >> >> Thanks Josh, that looks correct. >> >> It's a small point, but does the check against NULL actually make sense? >> I don't think we ever check other system table pointers against NULL. > > That I'm not sure of. I was going off of the assumption that Matthew > put it there because someone's EFI 2.0 implementation was crappy and > didn't actually implement it. So I left that check in place for now. I presume that if that were true, virt_efi_query_variable_info() (which is called indirectly from the efivars code) would have exploded before now. Matthew? -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
