lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20230612210712.683175-4-eric.devolder@oracle.com>
Date:   Mon, 12 Jun 2023 17:07:07 -0400
From:   Eric DeVolder <eric.devolder@...cle.com>
To:     linux-kernel@...r.kernel.org, david@...hat.com, osalvador@...e.de,
        corbet@....net, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, bhe@...hat.com,
        ebiederm@...ssion.com, kexec@...ts.infradead.org
Cc:     hpa@...or.com, gregkh@...uxfoundation.org, rafael@...nel.org,
        vgoyal@...hat.com, dyoung@...hat.com, lf32.dev@...il.com,
        akpm@...ux-foundation.org, naveen.n.rao@...ux.vnet.ibm.com,
        zohar@...ux.ibm.com, bhelgaas@...gle.com, vbabka@...e.cz,
        tiwai@...e.de, seanjc@...gle.com, linux@...ssschuh.net,
        vschneid@...hat.com, linux-mm@...ck.org, linux-doc@...r.kernel.org,
        sourabhjain@...ux.ibm.com, konrad.wilk@...cle.com,
        boris.ostrovsky@...cle.com, eric.devolder@...cle.com
Subject: [PATCH v23 3/8] kexec: exclude elfcorehdr from the segment digest

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. The digest is embedded into
the purgatory image prior to placing in memory.

Updates to the elfcorehdr in response to CPU and memory changes
would cause the purgatory integrity checking to fail (at crash time,
and no vmcore created). Therefore, the elfcorehdr segment is
explicitly excluded from the purgatory digest, enabling updates to
the elfcorehdr while also avoiding the need to recompute the hash
digest and reload purgatory.

Signed-off-by: Eric DeVolder <eric.devolder@...cle.com>
Reviewed-by: Sourabh Jain <sourabhjain@...ux.ibm.com>
Acked-by: Hari Bathini <hbathini@...ux.ibm.com>
Acked-by: Baoquan He <bhe@...hat.com>
---
 kernel/kexec_file.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index f8b1797b3ec9..1d2cfc869a75 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -726,6 +726,12 @@ 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
+		/* Exclude elfcorehdr segment to allow future changes via hotplug */
+		if (j == image->elfcorehdr_index)
+			continue;
+#endif
+
 		ksegment = &image->segment[i];
 		/*
 		 * Skip purgatory as it will be modified once we put digest
-- 
2.31.1

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ