Blame SOURCES/0313-relocator-Protect-grub_relocator_alloc_chunk_addr-in.patch

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From 0000000000000000000000000000000000000000 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] relocator: Protect grub_relocator_alloc_chunk_addr() input
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 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      | 21 ++++++++++++++++-----
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 grub-core/loader/xnu.c           | 11 +++++++----
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 4 files changed, 37 insertions(+), 13 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 656c75fd7e8..1a36979a5ec 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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@@ -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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@@ -586,9 +587,13 @@ 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 c2e5fa9abcc..4a801a7ab08 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 c16b4b24937..b6ec98bed98 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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@@ -39,6 +39,8 @@
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 #include <grub/xen.h>
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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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@@ -397,6 +399,11 @@ grub_cmd_xen (grub_command_t cmd __attribute__ ((unused)),
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   grub_file_t file;
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   grub_elf_t elf;
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   grub_err_t err;
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+  void *kern_chunk_src;
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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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@@ -448,9 +455,8 @@ grub_cmd_xen (grub_command_t cmd __attribute__ ((unused)),
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   if (!relocator)
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     goto fail;
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-  grub_relocator_chunk_t ch;
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-  grub_addr_t kern_start = xen_inf.kern_start - xen_inf.paddr_offset;
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-  grub_addr_t kern_end = xen_inf.kern_end - xen_inf.paddr_offset;
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+  kern_start = xen_inf.kern_start - xen_inf.paddr_offset;
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+  kern_end = xen_inf.kern_end - xen_inf.paddr_offset;
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   if (xen_inf.has_hypercall_page)
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     {
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@@ -465,8 +471,13 @@ grub_cmd_xen (grub_command_t cmd __attribute__ ((unused)),
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   max_addr = ALIGN_UP (kern_end, PAGE_SIZE);
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-  err = grub_relocator_alloc_chunk_addr (relocator, &ch, kern_start,
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-					 kern_end - kern_start);
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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 fdf61b6f9f7..66731d2528b 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;