(Pulling in Dave because he wrote parse_option_str())
On Tue, 30 Jun, at 04:13:33PM, Ricardo Neri wrote:
> Even though it is documented how to specify efi parameters,
> it is possible to cause a kernel panic due to a NULL pointer
> derreference if no efi parameter is passed. Thus, check whether
> there is any parameters at all before parsing and warn the user.
>
> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
> ---
> arch/x86/platform/efi/efi.c | 4 ++++
> drivers/firmware/efi/efi.c | 4 ++++
> 2 files changed, 8 insertions(+)
Did you hit this by passing "efi=" on the kernel command line?
I would have assumed that the generic early param parsing code would
have caught this problem since it's obviously a potential issue for
every other early_param() function, and so needs to be solved in a more
general way.
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 51a689d..f60af0c 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -948,6 +948,10 @@ 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 3c457db..c1b3fdb 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -58,6 +58,10 @@ 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;
>
> --
> 1.9.1
>
--
Matt Fleming, Intel Open Source Technology Center
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