From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric DeVolder Date: Tue, 1 Mar 2022 14:07:50 -0600 Subject: [PATCH v4 07/10] crash hp: exclude elfcorehdr from the segment digest In-Reply-To: References: <20220209195706.51522-1-eric.devolder@oracle.com> <20220209195706.51522-8-eric.devolder@oracle.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org On 2/22/22 22:00, Baoquan He wrote: > On 02/09/22 at 02:57pm, Eric DeVolder wrote: >> When a crash kernel is loaded via the kexec_file_load syscall, the >> kernel places the various segments (ie crash kernel, crash initrd, >> boot_params, elfcorehdr, purgatory, etc) in memory. For those >> architectures that utilize purgatory, a hash digest of the segments >> is calculated for integrity checking. This digest is embedded into >> the purgatory image prior to placing purgatory in memory. >> >> Since hotplug events cause changes to the elfcorehdr, purgatory >> integrity checking fails (at crash time, and no kdump created). >> As a result, this change explicitly excludes the elfcorehdr segment >> from the list of segments used to create the digest. By doing so, >> this permits changes to the elfcorehdr in response to hotplug events, >> without having to also reload purgatory due to the change to the >> digest. > > Acked-by: Baoquan He Thank you! eric > >> >> Signed-off-by: Eric DeVolder >> --- >> kernel/kexec_file.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c >> index 801d0d0a5012..93bb0c0ce66c 100644 >> --- a/kernel/kexec_file.c >> +++ b/kernel/kexec_file.c >> @@ -765,6 +765,12 @@ static int kexec_calculate_store_digests(struct kimage *image) >> for (j = i = 0; i < image->nr_segments; i++) { >> struct kexec_segment *ksegment; >> >> +#ifdef CONFIG_CRASH_HOTPLUG >> + /* This segment excluded to allow future changes via hotplug */ >> + if (image->elf_index_valid && (j == image->elf_index)) >> + continue; >> +#endif >> + >> ksegment = &image->segment[i]; >> /* >> * Skip purgatory as it will be modified once we put digest >> -- >> 2.27.0 >> >