[v1] x86 + misc changes for 2022-09-29

[PULL 03/14] x86: reinitialize RNG seed on system reboot

Paolo Bonzini posted 14 patches 3 years, 4 months ago

Diff against v2 v3
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Maintainers: Sergio Lopez <slp@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, "Philippe Mathieu-Daudé" <f4bug@amsat.org>, Gerd Hoffmann <kraxel@redhat.com>, "Cédric Le Goater" <clg@kaod.org>, Peter Maydell <peter.maydell@linaro.org>, Andrew Jeffery <andrew@aj.id.au>, Joel Stanley <joel@jms.id.au>, Cornelia Huck <cohuck@redhat.com>, Thomas Huth <thuth@redhat.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Jean-Christophe Dubois <jcd@tribudubois.net>, Michael Roth <michael.roth@amd.com>, Konstantin Kostiuk <kkostiuk@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Laurent Vivier <lvivier@redhat.com>

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[PULL 03/14] x86: reinitialize RNG seed on system reboot

Posted by Paolo Bonzini 3 years, 4 months ago

From: "Jason A. Donenfeld" <Jason@zx2c4.com>

Since this is read from fw_cfg on each boot, the kernel zeroing it out
alone is insufficient to prevent it from being used twice. And indeed on
reboot we always want a new seed, not the old one. So re-fill it in this
circumstance.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Message-Id: <20220921093134.2936487-3-Jason@zx2c4.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/i386/x86.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/i386/x86.c b/hw/i386/x86.c
index 1ee0b1b413..f9a4ddaa4a 100644
--- a/hw/i386/x86.c
+++ b/hw/i386/x86.c
@@ -783,6 +783,12 @@ static void reset_setup_data(void *opaque)
     stq_p(fixup->pos, fixup->orig_val);
 }
 
+static void reset_rng_seed(void *opaque)
+{
+    SetupData *setup_data = opaque;
+    qemu_guest_getrandom_nofail(setup_data->data, le32_to_cpu(setup_data->len));
+}
+
 void x86_load_linux(X86MachineState *x86ms,
                     FWCfgState *fw_cfg,
                     int acpi_data_size,
@@ -1105,6 +1111,7 @@ void x86_load_linux(X86MachineState *x86ms,
         setup_data->type = cpu_to_le32(SETUP_RNG_SEED);
         setup_data->len = cpu_to_le32(RNG_SEED_LENGTH);
         qemu_guest_getrandom_nofail(setup_data->data, RNG_SEED_LENGTH);
+        qemu_register_reset(reset_rng_seed, setup_data);
     }
 
     fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, prot_addr);
-- 
2.37.3