Re: [PATCH v4 6/7] x86/crash: pass dm crypt keys to kdump kernel

[Coiby Xu]

On Fri, Jun 07, 2024 at 05:57:38PM +0800, Baoquan He wrote:
> On 05/23/24 at 01:04pm, Coiby Xu wrote:
> > 1st kernel will build up the kernel command parameter dmcryptkeys as
> > similar to elfcorehdr to pass the memory address of the stored info of
> > dm crypt key to kdump kernel.
> >
> > Signed-off-by: Coiby Xu <coxu@xxxxxxxxxx>
> > ---
> >  arch/x86/kernel/crash.c           | 15 ++++++++++++++-
> >  arch/x86/kernel/kexec-bzimage64.c |  7 +++++++
> >  2 files changed, 21 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
> > index f06501445cd9..74b3844ae53c 100644
> > --- a/arch/x86/kernel/crash.c
> > +++ b/arch/x86/kernel/crash.c
> > @@ -266,6 +266,7 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
> >  				 unsigned long long mend)
> >  {
> >  	unsigned long start, end;
> > +	int r;
>            ~?
>
> r is only to contain the returned value? Then you can call it ret as
> many do in kernel code.

Applied to v6, thanks for the suggestion!

> >  	cmem->ranges[0].start = mstart;
> >  	cmem->ranges[0].end = mend;
> > @@ -274,7 +275,19 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
> >  	/* Exclude elf header region */
> >  	start = image->elf_load_addr;
> >  	end = start + image->elf_headers_sz - 1;
> > -	return crash_exclude_mem_range(cmem, start, end);
> > +	r = crash_exclude_mem_range(cmem, start, end);
> > +
> > +	if (r)
> > +		return r;
> > +
> > +	/* Exclude dm crypt keys region */
> > +	if (image->dm_crypt_keys_addr) {
> > +		start = image->dm_crypt_keys_addr;
> > +		end = start + image->dm_crypt_keys_sz - 1;
> > +		return crash_exclude_mem_range(cmem, start, end);
> > +	}
>
> You need adjust the array length of cmem->ranges[], I believe you will
> cause the array overflow because the keys are randomly set and mostly
> will be in the middle of crashkernel region.

Yes, you are absolutely right. I've fixed in v6.


--
Best regards,
Coiby