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From: Gerd Hoffmann <kraxel@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Yanan Wang" <wangyanan55@huawei.com>,
	"Zhao Liu" <zhao1.liu@intel.com>,
	"Eduardo Habkost" <eduardo@habkost.net>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Gerd Hoffmann" <kraxel@redhat.com>
Subject: [PATCH v2 2/5] x86/loader: only patch linux kernels
Date: Thu,  5 Sep 2024 16:12:07 +0200	[thread overview]
Message-ID: <20240905141211.1253307-3-kraxel@redhat.com> (raw)
In-Reply-To: <20240905141211.1253307-1-kraxel@redhat.com>

If the binary loaded via -kernel is *not* a linux kernel (in which
case protocol == 0), do not patch the linux kernel header fields.

It's (a) pointless and (b) might break binaries by random patching
and (c) changes the binary hash which in turn breaks secure boot
verification.

Background: OVMF happily loads and runs not only linux kernels but
any efi binary via direct kernel boot.

Note: Breaking the secure boot verification is a problem for linux
kernels too, but fixed that is left for another day ...

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/i386/x86-common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/i386/x86-common.c b/hw/i386/x86-common.c
index 992ea1f25e94..b52903c47fec 100644
--- a/hw/i386/x86-common.c
+++ b/hw/i386/x86-common.c
@@ -943,7 +943,7 @@ void x86_load_linux(X86MachineState *x86ms,
      * kernel on the other side of the fw_cfg interface matches the hash of the
      * file the user passed in.
      */
-    if (!sev_enabled()) {
+    if (!sev_enabled() && protocol > 0) {
         memcpy(setup, header, MIN(sizeof(header), setup_size));
     }
 
-- 
2.46.0



  parent reply	other threads:[~2024-09-05 14:13 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-05 14:12 [PATCH v2 0/5] x86/loader: secure boot support for direct kernel load Gerd Hoffmann
2024-09-05 14:12 ` [PATCH v2 1/5] vl: fix qemu_validate_options() indention Gerd Hoffmann
2024-09-05 14:12 ` Gerd Hoffmann [this message]
2024-09-05 14:12 ` [PATCH v2 3/5] x86/loader: read complete kernel Gerd Hoffmann
2024-09-05 14:12 ` [PATCH v2 4/5] x86/loader: expose unpatched kernel Gerd Hoffmann
2024-09-05 14:12 ` [PATCH v2 5/5] x86/loader: add -shim option Gerd Hoffmann

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