Blame SOURCES/0295-relocator-Protect-grub_relocator_alloc_chunk_addr-in.patch

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From 320fe69ffff39f90169f793402de4d4223a1a64c Mon Sep 17 00:00:00 2001
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From: Alexey Makhalov <amakhalov@vmware.com>
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Date: Wed, 15 Jul 2020 06:42:37 +0000
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Subject: [PATCH 295/314] relocator: Protect grub_relocator_alloc_chunk_addr()
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 input args against integer underflow/overflow
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Use arithmetic macros from safemath.h to accomplish it. In this commit,
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I didn't want to be too paranoid to check every possible math equation
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for overflow/underflow. Only obvious places (with non zero chance of
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overflow/underflow) were refactored.
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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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Upstream-commit-id: ebb15735f10
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---
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 grub-core/loader/i386/linux.c    |  9 +++++++--
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 grub-core/loader/i386/pc/linux.c |  9 +++++++--
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 grub-core/loader/i386/xen.c      | 12 ++++++++++--
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 grub-core/loader/xnu.c           | 11 +++++++----
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 4 files changed, 31 insertions(+), 10 deletions(-)
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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 76304f05700..b4a30f607fa 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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@@ -37,6 +37,7 @@
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 #include <grub/linux.h>
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 #include <grub/efi/sb.h>
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 #include <grub/tpm.h>
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+#include <grub/safemath.h>
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 GRUB_MOD_LICENSE ("GPLv3+");
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@@ -593,9 +594,13 @@ grub_linux_boot (void)
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   {
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     grub_relocator_chunk_t ch;
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+    grub_size_t sz;
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+
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+    if (grub_add (ctx.real_size, efi_mmap_size, &sz))
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+      return GRUB_ERR_OUT_OF_RANGE;
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+
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     err = grub_relocator_alloc_chunk_addr (relocator, &ch,
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-					   ctx.real_mode_target,
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-					   (ctx.real_size + efi_mmap_size));
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+					   ctx.real_mode_target, sz);
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     if (err)
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      return err;
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     real_mode_mem = 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 783a3cd93bc..540891371f9 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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@@ -36,6 +36,7 @@
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 #include <grub/lib/cmdline.h>
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 #include <grub/linux.h>
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 #include <grub/efi/sb.h>
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+#include <grub/safemath.h>
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 GRUB_MOD_LICENSE ("GPLv3+");
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@@ -231,8 +232,12 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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     setup_sects = GRUB_LINUX_DEFAULT_SETUP_SECTS;
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   real_size = setup_sects << GRUB_DISK_SECTOR_BITS;
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-  grub_linux16_prot_size = grub_file_size (file)
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-    - real_size - GRUB_DISK_SECTOR_SIZE;
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+  if (grub_sub (grub_file_size (file), real_size, &grub_linux16_prot_size) ||
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+      grub_sub (grub_linux16_prot_size, GRUB_DISK_SECTOR_SIZE, &grub_linux16_prot_size))
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+    {
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+      grub_error (GRUB_ERR_OUT_OF_RANGE, N_("overflow is detected"));
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+      goto fail;
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+    }
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   if (! grub_linux_is_bzimage
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       && GRUB_LINUX_ZIMAGE_ADDR + grub_linux16_prot_size
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diff --git a/grub-core/loader/i386/xen.c b/grub-core/loader/i386/xen.c
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index 3073f64d5e5..85b93347b25 100644
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--- a/grub-core/loader/i386/xen.c
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+++ b/grub-core/loader/i386/xen.c
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@@ -40,6 +40,7 @@
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 #include <grub/xen_file.h>
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 #include <grub/linux.h>
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 #include <grub/i386/memory.h>
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+#include <grub/safemath.h>
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 GRUB_MOD_LICENSE ("GPLv3+");
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@@ -635,6 +636,7 @@ grub_cmd_xen (grub_command_t cmd __attribute__ ((unused)),
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   grub_relocator_chunk_t ch;
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   grub_addr_t kern_start;
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   grub_addr_t kern_end;
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+  grub_size_t sz;
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   if (argc == 0)
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     return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
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@@ -699,8 +701,14 @@ grub_cmd_xen (grub_command_t cmd __attribute__ ((unused)),
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   xen_state.max_addr = ALIGN_UP (kern_end, PAGE_SIZE);
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-  err = grub_relocator_alloc_chunk_addr (xen_state.relocator, &ch, kern_start,
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-					 kern_end - kern_start);
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+
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+  if (grub_sub (kern_end, kern_start, &sz))
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+    {
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+      err = GRUB_ERR_OUT_OF_RANGE;
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+      goto fail;
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+    }
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+
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+  err = grub_relocator_alloc_chunk_addr (xen_state.relocator, &ch, kern_start, sz);
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   if (err)
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     goto fail;
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   kern_chunk_src = get_virtual_current_address (ch);
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diff --git a/grub-core/loader/xnu.c b/grub-core/loader/xnu.c
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index dc7d5409e1e..2bf02489bad 100644
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--- a/grub-core/loader/xnu.c
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+++ b/grub-core/loader/xnu.c
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@@ -34,6 +34,7 @@
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 #include <grub/env.h>
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 #include <grub/i18n.h>
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 #include <grub/efi/sb.h>
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+#include <grub/safemath.h>
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 GRUB_MOD_LICENSE ("GPLv3+");
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@@ -59,15 +60,17 @@ grub_xnu_heap_malloc (int size, void **src, grub_addr_t *target)
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 {
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   grub_err_t err;
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   grub_relocator_chunk_t ch;
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+  grub_addr_t tgt;
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+
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+  if (grub_add (grub_xnu_heap_target_start, grub_xnu_heap_size, &tgt))
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+    return GRUB_ERR_OUT_OF_RANGE;
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-  err = grub_relocator_alloc_chunk_addr (grub_xnu_relocator, &ch,
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-					 grub_xnu_heap_target_start
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-					 + grub_xnu_heap_size, size);
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+  err = grub_relocator_alloc_chunk_addr (grub_xnu_relocator, &ch, tgt, size);
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   if (err)
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     return err;
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   *src = get_virtual_current_address (ch);
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-  *target = grub_xnu_heap_target_start + grub_xnu_heap_size;
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+  *target = tgt;
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   grub_xnu_heap_size += size;
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   grub_dprintf ("xnu", "val=%p\n", *src);
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   return GRUB_ERR_NONE;
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-- 
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2.26.2
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