138 lines
3.9 KiB
Diff
138 lines
3.9 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Daniel Axtens <dja@axtens.net>
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Date: Mon, 28 Sep 2020 11:11:17 +1000
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Subject: [PATCH] ieee1275: link appended-signature enforcement to
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/ibm,secure-boot
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If the 'ibm,secure-boot' property of the root node is 2 or greater,
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require that the kernel pass appended-signature verification.
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Do not consider the presence of a certificate to enforce verification.
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Signed-off-by: Daniel Axtens <dja@axtens.net>
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---
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grub-core/commands/appendedsig/appendedsig.c | 44 +++++++++++++++++++++-------
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grub-core/kern/ieee1275/init.c | 26 ++++++++++++++++
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2 files changed, 60 insertions(+), 10 deletions(-)
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diff --git a/grub-core/commands/appendedsig/appendedsig.c b/grub-core/commands/appendedsig/appendedsig.c
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index 5d8897be5..4ef2ec289 100644
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--- a/grub-core/commands/appendedsig/appendedsig.c
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+++ b/grub-core/commands/appendedsig/appendedsig.c
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@@ -95,10 +95,24 @@ static char *
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grub_env_write_sec (struct grub_env_var *var __attribute__((unused)),
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const char *val)
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{
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+ if (check_sigs == 2)
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+ return grub_strdup ("forced");
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check_sigs = (*val == '1') || (*val == 'e');
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return grub_strdup (check_sigs ? "enforce" : "no");
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}
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+static const char *
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+grub_env_read_sec (struct grub_env_var *var __attribute__ ((unused)),
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+ const char *val __attribute__ ((unused)))
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+{
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+ if (check_sigs == 2)
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+ return "forced";
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+ else if (check_sigs == 1)
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+ return "enforce";
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+ else
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+ return "no";
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+}
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+
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static grub_err_t
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read_cert_from_file (grub_file_t f, struct x509_certificate *certificate)
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{
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@@ -552,14 +566,20 @@ GRUB_MOD_INIT (appendedsig)
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val = grub_env_get ("check_appended_signatures");
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grub_dprintf ("appendedsig", "check_appended_signatures='%s'\n", val);
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- if (val && (val[0] == '1' || val[0] == 'e'))
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- check_sigs = 1;
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- else
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- check_sigs = 0;
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+ if (val)
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+ {
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+ if (val[0] == '2' || val[0] == 'f')
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+ check_sigs = 2;
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+ else if (val[0] == '1' || val[0] == 'e')
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+ check_sigs = 1;
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+ else
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+ check_sigs = 0;
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+ }
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grub_trusted_key = NULL;
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- grub_register_variable_hook ("check_appended_signatures", 0,
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+ grub_register_variable_hook ("check_appended_signatures",
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+ grub_env_read_sec,
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grub_env_write_sec);
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grub_env_export ("check_appended_signatures");
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@@ -603,11 +623,15 @@ GRUB_MOD_INIT (appendedsig)
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grub_trusted_key = pk;
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}
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- if (!val || val[0] == '\0')
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- {
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- grub_env_set ("check_appended_signatures",
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- grub_trusted_key ? "enforce" : "no");
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- }
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+ /*
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+ * When controlled by ibm,secure-boot, we don't want the presence of
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+ * a certificate to enforce secure boot.
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+ * if (!val || val[0] == '\0')
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+ * {
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+ * grub_env_set ("check_appended_signatures",
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+ * grub_trusted_key ? "enforce" : "no");
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+ * }
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+ */
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cmd_trust =
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grub_register_command ("trust_certificate", grub_cmd_trust,
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diff --git a/grub-core/kern/ieee1275/init.c b/grub-core/kern/ieee1275/init.c
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index e731a57a4..22dc3013d 100644
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--- a/grub-core/kern/ieee1275/init.c
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+++ b/grub-core/kern/ieee1275/init.c
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@@ -268,6 +268,30 @@ grub_parse_cmdline (void)
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}
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}
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+static void
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+grub_get_ieee1275_secure_boot (void)
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+{
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+ grub_ieee1275_phandle_t root;
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+ int rc;
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+ grub_uint32_t is_sb;
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+
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+ grub_ieee1275_finddevice ("/", &root);
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+
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+ rc = grub_ieee1275_get_integer_property (root, "ibm,secure-boot", &is_sb,
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+ sizeof (is_sb), 0);
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+
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+ /* ibm,secure-boot:
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+ * 0 - disabled
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+ * 1 - audit
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+ * 2 - enforce
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+ * 3 - enforce + OS-specific behaviour
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+ *
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+ * We only support enforce.
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+ */
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+ if (rc >= 0 && is_sb >= 2)
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+ grub_env_set("check_appended_signatures", "forced");
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+}
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+
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grub_addr_t grub_modbase;
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void
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@@ -290,6 +314,8 @@ grub_machine_init (void)
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#else
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grub_install_get_time_ms (grub_rtc_get_time_ms);
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#endif
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+
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+ grub_get_ieee1275_secure_boot ();
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}
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void
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