Blame SOURCES/0333-verifiers-Add-possibility-to-defer-verification-to-o.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Daniel Kiper <daniel.kiper@oracle.com>
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Date: Wed, 26 Sep 2018 13:17:52 +0200
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Subject: [PATCH] verifiers: Add possibility to defer verification to other
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 verifiers
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This way if a verifier requires verification of a given file it can defer task
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to another verifier (another authority) if it is not able to do it itself. E.g.
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shim_lock verifier, posted as a subsequent patch, is able to verify only PE
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files. This means that it is not able to verify any of GRUB2 modules which have
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to be trusted on UEFI systems with secure boot enabled. So, it can defer
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verification to other verifier, e.g. PGP one.
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I silently assume that other verifiers are trusted and will do good job for us.
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Or at least they will not do any harm.
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Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
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Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
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---
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 grub-core/commands/verifiers.c | 23 ++++++++++++++++++++---
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 include/grub/verify.h          |  4 +++-
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 2 files changed, 23 insertions(+), 4 deletions(-)
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diff --git a/grub-core/commands/verifiers.c b/grub-core/commands/verifiers.c
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index 59ea418a2..c638d5f43 100644
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--- a/grub-core/commands/verifiers.c
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+++ b/grub-core/commands/verifiers.c
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@@ -83,6 +83,7 @@ grub_verifiers_open (grub_file_t io, enum grub_file_type type)
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   void *context;
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   grub_file_t ret = 0;
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   grub_err_t err;
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+  int defer = 0;
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   grub_dprintf ("verify", "file: %s type: %d\n", io->name, type);
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@@ -102,13 +103,27 @@ grub_verifiers_open (grub_file_t io, enum grub_file_type type)
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       err = ver->init (io, type, &context, &flags);
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       if (err)
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 	goto fail_noclose;
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+      if (flags & GRUB_VERIFY_FLAGS_DEFER_AUTH)
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+	{
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+	  defer = 1;
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+	  continue;
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+	}
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       if (!(flags & GRUB_VERIFY_FLAGS_SKIP_VERIFICATION))
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 	break;
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     }
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   if (!ver)
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-    /* No verifiers wanted to verify. Just return underlying file. */
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-    return io;
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+    {
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+      if (defer)
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+	{
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+	  grub_error (GRUB_ERR_ACCESS_DENIED,
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+		      N_("verification requested but nobody cares: %s"), io->name);
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+	  goto fail_noclose;
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+	}
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+
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+      /* No verifiers wanted to verify. Just return underlying file. */
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+      return io;
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+    }
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   ret = grub_malloc (sizeof (*ret));
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   if (!ret)
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@@ -160,7 +175,9 @@ grub_verifiers_open (grub_file_t io, enum grub_file_type type)
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       err = ver->init (io, type, &context, &flags);
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       if (err)
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 	goto fail_noclose;
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-      if (flags & GRUB_VERIFY_FLAGS_SKIP_VERIFICATION)
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+      if (flags & GRUB_VERIFY_FLAGS_SKIP_VERIFICATION ||
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+	  /* Verification done earlier. So, we are happy here. */
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+	  flags & GRUB_VERIFY_FLAGS_DEFER_AUTH)
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 	continue;
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       err = ver->write (context, verified->buf, ret->size);
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       if (err)
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diff --git a/include/grub/verify.h b/include/grub/verify.h
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index 9f892d8fe..79022b422 100644
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--- a/include/grub/verify.h
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+++ b/include/grub/verify.h
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@@ -22,7 +22,9 @@
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 enum grub_verify_flags
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   {
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     GRUB_VERIFY_FLAGS_SKIP_VERIFICATION	= 1,
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-    GRUB_VERIFY_FLAGS_SINGLE_CHUNK	= 2
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+    GRUB_VERIFY_FLAGS_SINGLE_CHUNK	= 2,
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+    /* Defer verification to another authority. */
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+    GRUB_VERIFY_FLAGS_DEFER_AUTH	= 4
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   };
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 enum grub_verify_string_type