[PATCH] build_mem_phdrs(): check if p_paddr is invalid

[Dave Young]

On 03/01/17 at 11:19am, Pratyush Anand wrote:
> Currently, all the p_paddr of PT_LOAD headers are assigned to 0, which
> is not correct and could be misleading, since 0 is a valid physical
> address.
> 
> Upstream kernel commit "464920104bf7 /proc/kcore: update physical
> address for kcore ram and text" fixed it and now invalid PT_LOAD is
> assigned as -1.
> 
> kexec/arch/i386/crashdump-x86.c:get_kernel_vaddr_and_size() uses kcore
> interface and so calls build_mem_phdrs() for kcore PT_LOAD headers.
> 
> This patch fixes build_mem_phdrs() to check if p_paddr is invalid.
> 
> Signed-off-by: Pratyush Anand <panand at redhat.com>
> ---
>  kexec/kexec-elf.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kexec/kexec-elf.c b/kexec/kexec-elf.c
> index 1d6320a2f0e6..be60bbd48486 100644
> --- a/kexec/kexec-elf.c
> +++ b/kexec/kexec-elf.c
> @@ -432,7 +432,8 @@ static int build_mem_phdrs(const char *buf, off_t len, struct mem_ehdr *ehdr,
>  			}
>  			return -1;
>  		}
> -		if ((phdr->p_paddr + phdr->p_memsz) < phdr->p_paddr) {
> +		if (phdr->p_paddr != (unsigned long long)-1 &&
> +			(phdr->p_paddr + phdr->p_memsz) < phdr->p_paddr) {
>  			/* The memory address wraps */
>  			if (probe_debug) {
>  				fprintf(stderr, "ELF address wrap around\n");
> -- 
> 2.9.3
> 

Acked-by: Dave Young <dyoung at redhat.com>

Thanks
Dave