From 0cfbbca3ccd84d36ffb1bcd6644ada7c73b19fc0 Mon Sep 17 00:00:00 2001
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From: Alexey Makhalov <amakhalov@vmware.com>
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Date: Wed, 8 Jul 2020 01:44:38 +0000
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Subject: [PATCH] relocator: Protect grub_relocator_alloc_chunk_align()
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max_addr against integer underflow
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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This commit introduces integer underflow mitigation in max_addr calculation
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in grub_relocator_alloc_chunk_align() invocation.
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It consists of 2 fixes:
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1. Introduced grub_relocator_alloc_chunk_align_safe() wrapper function to perform
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sanity check for min/max and size values, and to make safe invocation of
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grub_relocator_alloc_chunk_align() with validated max_addr value. Replace all
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invocations such as grub_relocator_alloc_chunk_align(..., min_addr, max_addr - size, size, ...)
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by grub_relocator_alloc_chunk_align_safe(..., min_addr, max_addr, size, ...).
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2. Introduced UP_TO_TOP32(s) macro for the cases where max_addr is 32-bit top
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address (0xffffffff - size + 1) or similar.
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Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
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---
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grub-core/lib/i386/relocator.c | 28 ++++++++++----------------
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grub-core/lib/mips/relocator.c | 6 ++----
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grub-core/lib/powerpc/relocator.c | 6 ++----
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grub-core/lib/x86_64/efi/relocator.c | 7 +++----
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grub-core/loader/i386/linux.c | 5 ++---
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grub-core/loader/i386/multiboot_mbi.c | 7 +++----
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grub-core/loader/i386/pc/linux.c | 6 ++----
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grub-core/loader/mips/linux.c | 9 +++------
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grub-core/loader/multiboot.c | 2 +-
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grub-core/loader/multiboot_elfxx.c | 10 ++++-----
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grub-core/loader/multiboot_mbi2.c | 10 ++++-----
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grub-core/loader/xnu_resume.c | 2 +-
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include/grub/relocator.h | 29 +++++++++++++++++++++++++++
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13 files changed, 69 insertions(+), 58 deletions(-)
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diff --git a/grub-core/lib/i386/relocator.c b/grub-core/lib/i386/relocator.c
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index 71dd4f0ab..34cbe834f 100644
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--- a/grub-core/lib/i386/relocator.c
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+++ b/grub-core/lib/i386/relocator.c
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@@ -83,11 +83,10 @@ grub_relocator32_boot (struct grub_relocator *rel,
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/* Specific memory range due to Global Descriptor Table for use by payload
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that we will store in returned chunk. The address range and preference
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are based on "THE LINUX/x86 BOOT PROTOCOL" specification. */
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- err = grub_relocator_alloc_chunk_align (rel, &ch, 0x1000,
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- 0x9a000 - RELOCATOR_SIZEOF (32),
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- RELOCATOR_SIZEOF (32), 16,
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- GRUB_RELOCATOR_PREFERENCE_LOW,
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- avoid_efi_bootservices);
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+ err = grub_relocator_alloc_chunk_align_safe (rel, &ch, 0x1000, 0x9a000,
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+ RELOCATOR_SIZEOF (32), 16,
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+ GRUB_RELOCATOR_PREFERENCE_LOW,
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+ avoid_efi_bootservices);
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if (err)
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return err;
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@@ -125,13 +124,10 @@ grub_relocator16_boot (struct grub_relocator *rel,
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grub_relocator_chunk_t ch;
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/* Put it higher than the byte it checks for A20 check. */
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- err = grub_relocator_alloc_chunk_align (rel, &ch, 0x8010,
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- 0xa0000 - RELOCATOR_SIZEOF (16)
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- - GRUB_RELOCATOR16_STACK_SIZE,
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- RELOCATOR_SIZEOF (16)
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- + GRUB_RELOCATOR16_STACK_SIZE, 16,
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- GRUB_RELOCATOR_PREFERENCE_NONE,
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- 0);
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+ err = grub_relocator_alloc_chunk_align_safe (rel, &ch, 0x8010, 0xa0000,
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+ RELOCATOR_SIZEOF (16) +
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+ GRUB_RELOCATOR16_STACK_SIZE, 16,
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+ GRUB_RELOCATOR_PREFERENCE_NONE, 0);
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if (err)
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return err;
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@@ -183,11 +179,9 @@ grub_relocator64_boot (struct grub_relocator *rel,
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void *relst;
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grub_relocator_chunk_t ch;
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- err = grub_relocator_alloc_chunk_align (rel, &ch, min_addr,
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- max_addr - RELOCATOR_SIZEOF (64),
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- RELOCATOR_SIZEOF (64), 16,
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- GRUB_RELOCATOR_PREFERENCE_NONE,
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- 0);
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+ err = grub_relocator_alloc_chunk_align_safe (rel, &ch, min_addr, max_addr,
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+ RELOCATOR_SIZEOF (64), 16,
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+ GRUB_RELOCATOR_PREFERENCE_NONE, 0);
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if (err)
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return err;
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diff --git a/grub-core/lib/mips/relocator.c b/grub-core/lib/mips/relocator.c
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index 9d5f49cb9..743b213e6 100644
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--- a/grub-core/lib/mips/relocator.c
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+++ b/grub-core/lib/mips/relocator.c
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@@ -120,10 +120,8 @@ grub_relocator32_boot (struct grub_relocator *rel,
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unsigned i;
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grub_addr_t vtarget;
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- err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
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- (0xffffffff - stateset_size)
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- + 1, stateset_size,
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- sizeof (grub_uint32_t),
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+ err = grub_relocator_alloc_chunk_align (rel, &ch, 0, UP_TO_TOP32 (stateset_size),
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+ stateset_size, sizeof (grub_uint32_t),
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GRUB_RELOCATOR_PREFERENCE_NONE, 0);
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if (err)
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return err;
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diff --git a/grub-core/lib/powerpc/relocator.c b/grub-core/lib/powerpc/relocator.c
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index bdf2b111b..8ffb8b686 100644
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--- a/grub-core/lib/powerpc/relocator.c
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+++ b/grub-core/lib/powerpc/relocator.c
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@@ -115,10 +115,8 @@ grub_relocator32_boot (struct grub_relocator *rel,
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unsigned i;
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grub_relocator_chunk_t ch;
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- err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
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- (0xffffffff - stateset_size)
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- + 1, stateset_size,
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- sizeof (grub_uint32_t),
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+ err = grub_relocator_alloc_chunk_align (rel, &ch, 0, UP_TO_TOP32 (stateset_size),
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+ stateset_size, sizeof (grub_uint32_t),
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GRUB_RELOCATOR_PREFERENCE_NONE, 0);
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if (err)
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return err;
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diff --git a/grub-core/lib/x86_64/efi/relocator.c b/grub-core/lib/x86_64/efi/relocator.c
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index 3caef7a40..7d200a125 100644
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--- a/grub-core/lib/x86_64/efi/relocator.c
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+++ b/grub-core/lib/x86_64/efi/relocator.c
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@@ -50,10 +50,9 @@ grub_relocator64_efi_boot (struct grub_relocator *rel,
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* 64-bit relocator code may live above 4 GiB quite well.
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* However, I do not want ask for problems. Just in case.
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*/
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- err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
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- 0x100000000 - RELOCATOR_SIZEOF (64_efi),
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- RELOCATOR_SIZEOF (64_efi), 16,
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- GRUB_RELOCATOR_PREFERENCE_NONE, 1);
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+ err = grub_relocator_alloc_chunk_align_safe (rel, &ch, 0, 0x100000000,
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+ RELOCATOR_SIZEOF (64_efi), 16,
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+ GRUB_RELOCATOR_PREFERENCE_NONE, 1);
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if (err)
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return err;
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diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c
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index 02a73463a..efbb99307 100644
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--- a/grub-core/loader/i386/linux.c
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+++ b/grub-core/loader/i386/linux.c
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@@ -181,9 +181,8 @@ allocate_pages (grub_size_t prot_size, grub_size_t *align,
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for (; err && *align + 1 > min_align; (*align)--)
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{
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grub_errno = GRUB_ERR_NONE;
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- err = grub_relocator_alloc_chunk_align (relocator, &ch,
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- 0x1000000,
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- 0xffffffff & ~prot_size,
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+ err = grub_relocator_alloc_chunk_align (relocator, &ch, 0x1000000,
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+ UP_TO_TOP32 (prot_size),
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prot_size, 1 << *align,
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GRUB_RELOCATOR_PREFERENCE_LOW,
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1);
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diff --git a/grub-core/loader/i386/multiboot_mbi.c b/grub-core/loader/i386/multiboot_mbi.c
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index ad3cc292f..a67d9d0a8 100644
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--- a/grub-core/loader/i386/multiboot_mbi.c
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+++ b/grub-core/loader/i386/multiboot_mbi.c
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@@ -466,10 +466,9 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
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bufsize = grub_multiboot_get_mbi_size ();
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- err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator, &ch,
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- 0x10000, 0xa0000 - bufsize,
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- bufsize, 4,
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- GRUB_RELOCATOR_PREFERENCE_NONE, 0);
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+ err = grub_relocator_alloc_chunk_align_safe (grub_multiboot_relocator, &ch,
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+ 0x10000, 0xa0000, bufsize, 4,
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+ GRUB_RELOCATOR_PREFERENCE_NONE, 0);
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if (err)
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return err;
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ptrorig = get_virtual_current_address (ch);
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diff --git a/grub-core/loader/i386/pc/linux.c b/grub-core/loader/i386/pc/linux.c
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index 31f09922b..5fed5ffdf 100644
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--- a/grub-core/loader/i386/pc/linux.c
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+++ b/grub-core/loader/i386/pc/linux.c
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@@ -453,10 +453,8 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
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{
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grub_relocator_chunk_t ch;
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- err = grub_relocator_alloc_chunk_align (relocator, &ch,
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- addr_min, addr_max - size,
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- size, 0x1000,
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- GRUB_RELOCATOR_PREFERENCE_HIGH, 0);
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+ err = grub_relocator_alloc_chunk_align_safe (relocator, &ch, addr_min, addr_max, size,
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+ 0x1000, GRUB_RELOCATOR_PREFERENCE_HIGH, 0);
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if (err)
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return err;
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initrd_chunk = get_virtual_current_address (ch);
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diff --git a/grub-core/loader/mips/linux.c b/grub-core/loader/mips/linux.c
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index 7b723bf18..e4ed95921 100644
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--- a/grub-core/loader/mips/linux.c
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+++ b/grub-core/loader/mips/linux.c
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@@ -442,12 +442,9 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
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{
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grub_relocator_chunk_t ch;
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- err = grub_relocator_alloc_chunk_align (relocator, &ch,
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- (target_addr & 0x1fffffff)
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- + linux_size + 0x10000,
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- (0x10000000 - size),
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- size, 0x10000,
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- GRUB_RELOCATOR_PREFERENCE_NONE, 0);
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+ err = grub_relocator_alloc_chunk_align_safe (relocator, &ch, (target_addr & 0x1fffffff) +
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+ linux_size + 0x10000, 0x10000000, size,
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+ 0x10000, GRUB_RELOCATOR_PREFERENCE_NONE, 0);
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if (err)
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goto fail;
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diff --git a/grub-core/loader/multiboot.c b/grub-core/loader/multiboot.c
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index 4a98d7082..facb13f3d 100644
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--- a/grub-core/loader/multiboot.c
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+++ b/grub-core/loader/multiboot.c
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@@ -403,7 +403,7 @@ grub_cmd_module (grub_command_t cmd __attribute__ ((unused)),
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{
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grub_relocator_chunk_t ch;
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err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch,
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- lowest_addr, (0xffffffff - size) + 1,
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+ lowest_addr, UP_TO_TOP32 (size),
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size, MULTIBOOT_MOD_ALIGN,
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GRUB_RELOCATOR_PREFERENCE_NONE, 1);
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if (err)
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diff --git a/grub-core/loader/multiboot_elfxx.c b/grub-core/loader/multiboot_elfxx.c
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index cc6853692..f2318e0d1 100644
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--- a/grub-core/loader/multiboot_elfxx.c
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+++ b/grub-core/loader/multiboot_elfxx.c
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@@ -109,10 +109,10 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
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if (load_size > mld->max_addr || mld->min_addr > mld->max_addr - load_size)
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return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or load size");
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- err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch,
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- mld->min_addr, mld->max_addr - load_size,
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- load_size, mld->align ? mld->align : 1,
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- mld->preference, mld->avoid_efi_boot_services);
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+ err = grub_relocator_alloc_chunk_align_safe (GRUB_MULTIBOOT (relocator), &ch,
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+ mld->min_addr, mld->max_addr,
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+ load_size, mld->align ? mld->align : 1,
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+ mld->preference, mld->avoid_efi_boot_services);
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if (err)
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{
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@@ -256,7 +256,7 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
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continue;
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err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch, 0,
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- (0xffffffff - sh->sh_size) + 1,
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+ UP_TO_TOP32 (sh->sh_size),
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sh->sh_size, sh->sh_addralign,
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GRUB_RELOCATOR_PREFERENCE_NONE,
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mld->avoid_efi_boot_services);
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diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
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index 0efc66062..03967839c 100644
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--- a/grub-core/loader/multiboot_mbi2.c
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+++ b/grub-core/loader/multiboot_mbi2.c
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@@ -295,10 +295,10 @@ grub_multiboot2_load (grub_file_t file, const char *filename)
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return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or load size");
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}
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- err = grub_relocator_alloc_chunk_align (grub_multiboot2_relocator, &ch,
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- mld.min_addr, mld.max_addr - code_size,
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- code_size, mld.align ? mld.align : 1,
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- mld.preference, keep_bs);
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+ err = grub_relocator_alloc_chunk_align_safe (grub_multiboot2_relocator, &ch,
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+ mld.min_addr, mld.max_addr,
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+ code_size, mld.align ? mld.align : 1,
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+ mld.preference, keep_bs);
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}
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else
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err = grub_relocator_alloc_chunk_addr (grub_multiboot2_relocator,
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@@ -708,7 +708,7 @@ grub_multiboot2_make_mbi (grub_uint32_t *target)
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COMPILE_TIME_ASSERT (MULTIBOOT_TAG_ALIGN % sizeof (grub_properly_aligned_t) == 0);
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err = grub_relocator_alloc_chunk_align (grub_multiboot2_relocator, &ch,
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- 0, 0xffffffff - bufsize,
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+ 0, UP_TO_TOP32 (bufsize),
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bufsize, MULTIBOOT_TAG_ALIGN,
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GRUB_RELOCATOR_PREFERENCE_NONE, 1);
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if (err)
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diff --git a/grub-core/loader/xnu_resume.c b/grub-core/loader/xnu_resume.c
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index 8089804d4..d648ef0cd 100644
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--- a/grub-core/loader/xnu_resume.c
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+++ b/grub-core/loader/xnu_resume.c
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@@ -129,7 +129,7 @@ grub_xnu_resume (char *imagename)
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{
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grub_relocator_chunk_t ch;
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err = grub_relocator_alloc_chunk_align (grub_xnu_relocator, &ch, 0,
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- (0xffffffff - hibhead.image_size) + 1,
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+ UP_TO_TOP32 (hibhead.image_size),
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hibhead.image_size,
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GRUB_XNU_PAGESIZE,
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GRUB_RELOCATOR_PREFERENCE_NONE, 0);
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diff --git a/include/grub/relocator.h b/include/grub/relocator.h
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index 24d8672d2..1b3bdd92a 100644
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--- a/include/grub/relocator.h
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+++ b/include/grub/relocator.h
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@@ -49,6 +49,35 @@ grub_relocator_alloc_chunk_align (struct grub_relocator *rel,
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int preference,
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int avoid_efi_boot_services);
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+/*
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+ * Wrapper for grub_relocator_alloc_chunk_align() with purpose of
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+ * protecting against integer underflow.
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+ *
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+ * Compare to its callee, max_addr has different meaning here.
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+ * It covers entire chunk and not just start address of the chunk.
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+ */
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+static inline grub_err_t
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+grub_relocator_alloc_chunk_align_safe (struct grub_relocator *rel,
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+ grub_relocator_chunk_t *out,
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+ grub_phys_addr_t min_addr,
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+ grub_phys_addr_t max_addr,
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+ grub_size_t size, grub_size_t align,
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+ int preference,
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+ int avoid_efi_boot_services)
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+{
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+ /* Sanity check and ensure following equation (max_addr - size) is safe. */
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+ if (max_addr < size || (max_addr - size) < min_addr)
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+ return GRUB_ERR_OUT_OF_RANGE;
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+
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+ return grub_relocator_alloc_chunk_align (rel, out, min_addr,
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+ max_addr - size,
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+ size, align, preference,
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+ avoid_efi_boot_services);
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+}
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+
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+/* Top 32-bit address minus s bytes and plus 1 byte. */
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+#define UP_TO_TOP32(s) ((~(s) & 0xffffffff) + 1)
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+
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#define GRUB_RELOCATOR_PREFERENCE_NONE 0
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#define GRUB_RELOCATOR_PREFERENCE_LOW 1
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#define GRUB_RELOCATOR_PREFERENCE_HIGH 2
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--
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2.26.2
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