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57 lines
1.8 KiB
57 lines
1.8 KiB
2 years ago
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Daniel Axtens <dja@axtens.net>
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Date: Thu, 21 Apr 2022 15:24:14 +1000
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Subject: [PATCH] mm: Assert that we preserve header vs region alignment
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grub_mm_region_init() does:
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h = (grub_mm_header_t) (r + 1);
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where h is a grub_mm_header_t and r is a grub_mm_region_t.
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Cells are supposed to be GRUB_MM_ALIGN aligned, but while grub_mm_dump
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ensures this vs the region header, grub_mm_region_init() does not.
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It's better to be explicit than implicit here: rather than changing
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grub_mm_region_init() to ALIGN_UP(), require that the struct is
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explicitly a multiple of the header size.
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Signed-off-by: Daniel Axtens <dja@axtens.net>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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Tested-by: Patrick Steinhardt <ps@pks.im>
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(cherry picked from commit 1df8fe66c57087eb33bd6dc69f786ed124615aa7)
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---
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include/grub/mm_private.h | 14 ++++++++++++++
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1 file changed, 14 insertions(+)
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diff --git a/include/grub/mm_private.h b/include/grub/mm_private.h
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index 203533cc3d..a688b92a83 100644
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--- a/include/grub/mm_private.h
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+++ b/include/grub/mm_private.h
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@@ -20,6 +20,7 @@
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#define GRUB_MM_PRIVATE_H 1
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#include <grub/mm.h>
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+#include <grub/misc.h>
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/* For context, see kern/mm.c */
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@@ -89,4 +90,17 @@ typedef struct grub_mm_region
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extern grub_mm_region_t EXPORT_VAR (grub_mm_base);
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#endif
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+static inline void
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+grub_mm_size_sanity_check (void) {
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+ /* Ensure we preserve alignment when doing h = (grub_mm_header_t) (r + 1). */
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+ COMPILE_TIME_ASSERT ((sizeof (struct grub_mm_region) %
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+ sizeof (struct grub_mm_header)) == 0);
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+
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+ /*
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+ * GRUB_MM_ALIGN is supposed to represent cell size, and a mm_header is
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+ * supposed to be 1 cell.
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+ */
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+ COMPILE_TIME_ASSERT (sizeof (struct grub_mm_header) == GRUB_MM_ALIGN);
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+}
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+
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#endif
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