asan: readelf: process_mips_specific buffer overflow

DT_MIPS_OPTIONS is not a regular array as assumed by readelf.  This
patch corrects that assumption, and to do so easily, makes various
internal (host byte order) structs the same size as external (target
byte order) structs.

include/
	* elf/mips.h (Elf32_RegInfo): Use fixed width integer types.
	(Elf64_Internal_RegInfo, Elf_Internal_Options): Likewise.
binutils/
	* readelf.c (process_mips_specific): Assert size of internal
	types match size of external types, and simplify allocation of
	internal buffer.  Catch possible integer overflow when sanity
	checking option size.  Don't assume options are a regular array.
	Sanity check reginfo option against option size.  Use PRI macros
	when printing.

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 43eabaa04412aedaba50b7d738b00179cdb9a6a2..25e21ff6dca168c18fc7a9eadbba8b1eefed066b 100644 (file)
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,12 @@
+2020-06-11  Alan Modra  <amodra@gmail.com>
+
+       * readelf.c (process_mips_specific): Assert size of internal
+       types match size of external types, and simplify allocation of
+       internal buffer.  Catch possible integer overflow when sanity
+       checking option size.  Don't assume options are a regular array.
+       Sanity check reginfo option against option size.  Use PRI macros
+       when printing.
+
 2020-06-10  Ralf Habacker  <ralf.habacker@freenet.de>
 
        PR 26082

diff --git a/binutils/readelf.c b/binutils/readelf.c
index 0bdabccc8eb140898254835309ecbb3482f4cc8d..0705a49c0d8b9573834bb793ed3b812a46c52577 100644 (file)
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -16896,10 +16896,11 @@ process_mips_specific (Filedata * filedata)
        {
          Elf_Internal_Options * iopt;
          Elf_Internal_Options * option;
-         Elf_Internal_Options * iopt_end;
 
-         iopt = (Elf_Internal_Options *)
-              cmalloc ((sect->sh_size / sizeof (eopt)), sizeof (* iopt));
+         assert (sizeof (Elf_Internal_Options) == sizeof (Elf_External_Options));
+         assert (sizeof (Elf32_RegInfo) == sizeof (Elf32_External_RegInfo));
+         assert (sizeof (Elf64_Internal_RegInfo) == sizeof (Elf64_External_RegInfo));
+         iopt = (Elf_Internal_Options *) cmalloc (sect->sh_size, 1);
          if (iopt == NULL)
            {
              error (_("Out of memory allocating space for MIPS options\n"));
@@ -16909,7 +16910,6 @@ process_mips_specific (Filedata * filedata)
 
          offset = cnt = 0;
          option = iopt;
-         iopt_end = iopt + (sect->sh_size / sizeof (eopt));
          
          while (offset <= sect->sh_size - sizeof (* eopt))
            {
@@ -16924,7 +16924,7 @@ process_mips_specific (Filedata * filedata)
 
              /* PR 17531: file: ffa0fa3b.  */
              if (option->size < sizeof (* eopt)
-                 || offset + option->size > sect->sh_size)
+                 || option->size > sect->sh_size - offset)
                {
                  error (_("Invalid size (%u) for MIPS option\n"),
                         option->size);
@@ -16943,18 +16943,18 @@ process_mips_specific (Filedata * filedata)
                            cnt),
                  printable_section_name (filedata, sect), cnt);
 
-         option = iopt;
          offset = 0;
-
          while (cnt-- > 0)
            {
              size_t len;
 
+             option = (Elf_Internal_Options *) ((char *) iopt + offset);
              switch (option->kind)
                {
                case ODK_NULL:
                  /* This shouldn't happen.  */
-                 printf (" NULL       %d %lx", option->section, option->info);
+                 printf (" NULL       %" PRId16 " %" PRIx32,
+                         option->section, option->info);
                  break;
 
                case ODK_REGINFO:
@@ -16965,7 +16965,8 @@ process_mips_specific (Filedata * filedata)
                      Elf32_RegInfo reginfo;
 
                      /* 32bit form.  */
-                     if (option + 2 > iopt_end)
+                     if (option->size < (sizeof (Elf_External_Options)
+                                         + sizeof (Elf32_External_RegInfo)))
                        {
                          printf (_("<corrupt>\n"));
                          error (_("Truncated MIPS REGINFO option\n"));
@@ -16982,10 +16983,11 @@ process_mips_specific (Filedata * filedata)
                      reginfo.ri_cprmask[3] = BYTE_GET (ereg->ri_cprmask[3]);
                      reginfo.ri_gp_value = BYTE_GET (ereg->ri_gp_value);
 
-                     printf ("GPR %08lx  GP 0x%lx\n",
-                             reginfo.ri_gprmask,
-                             (unsigned long) reginfo.ri_gp_value);
-                     printf ("            CPR0 %08lx  CPR1 %08lx  CPR2 %08lx  CPR3 %08lx\n",
+                     printf ("GPR %08" PRIx32 "  GP 0x%" PRIx32 "\n",
+                             reginfo.ri_gprmask, reginfo.ri_gp_value);
+                     printf ("          "
+                             "  CPR0 %08" PRIx32 "  CPR1 %08" PRIx32
+                             "  CPR2 %08" PRIx32 "  CPR3 %08" PRIx32 "\n",
                              reginfo.ri_cprmask[0], reginfo.ri_cprmask[1],
                              reginfo.ri_cprmask[2], reginfo.ri_cprmask[3]);
                    }
@@ -16995,7 +16997,8 @@ process_mips_specific (Filedata * filedata)
                      Elf64_External_RegInfo * ereg;
                      Elf64_Internal_RegInfo reginfo;
 
-                     if (option + 2 > iopt_end)
+                     if (option->size < (sizeof (Elf_External_Options)
+                                         + sizeof (Elf64_External_RegInfo)))
                        {
                          printf (_("<corrupt>\n"));
                          error (_("Truncated MIPS REGINFO option\n"));
@@ -17011,16 +17014,15 @@ process_mips_specific (Filedata * filedata)
                      reginfo.ri_cprmask[3] = BYTE_GET (ereg->ri_cprmask[3]);
                      reginfo.ri_gp_value   = BYTE_GET (ereg->ri_gp_value);
 
-                     printf ("GPR %08lx  GP 0x",
-                             reginfo.ri_gprmask);
-                     printf_vma (reginfo.ri_gp_value);
-                     printf ("\n");
-
-                     printf ("            CPR0 %08lx  CPR1 %08lx  CPR2 %08lx  CPR3 %08lx\n",
+                     printf ("GPR %08" PRIx32 "  GP 0x%" PRIx64 "\n",
+                             reginfo.ri_gprmask, reginfo.ri_gp_value);
+                     printf ("          "
+                             "  CPR0 %08" PRIx32 "  CPR1 %08" PRIx32
+                             "  CPR2 %08" PRIx32 "  CPR3 %08" PRIx32 "\n",
                              reginfo.ri_cprmask[0], reginfo.ri_cprmask[1],
                              reginfo.ri_cprmask[2], reginfo.ri_cprmask[3]);
                    }
-                 ++option;
+                 offset += option->size;
                  continue;
 
                case ODK_EXCEPTIONS:
@@ -17089,20 +17091,20 @@ process_mips_specific (Filedata * filedata)
                  break;
 
                case ODK_GP_GROUP:
-                 printf (" GP_GROUP  %#06lx  self-contained %#06lx",
+                 printf (" GP_GROUP  %#06x  self-contained %#06x",
                          option->info & OGP_GROUP,
                          (option->info & OGP_SELF) >> 16);
                  break;
 
                case ODK_IDENT:
-                 printf (" IDENT     %#06lx  self-contained %#06lx",
+                 printf (" IDENT     %#06x  self-contained %#06x",
                          option->info & OGP_GROUP,
                          (option->info & OGP_SELF) >> 16);
                  break;
 
                default:
                  /* This shouldn't happen.  */
-                 printf (" %3d ???     %d %lx",
+                 printf (" %3d ???     %" PRId16 " %" PRIx32,
                          option->kind, option->section, option->info);
                  break;
                }
@@ -17121,7 +17123,6 @@ process_mips_specific (Filedata * filedata)
              fputs ("\n", stdout);
 
              offset += option->size;
-             ++option;
            }
          free (iopt);
          free (eopt);

diff --git a/include/ChangeLog b/include/ChangeLog
index f6200db75c1ccb67fcb59fa8f70c99f2d97cfe12..3c2765274d413b600cfbd879437b4d8923cca7ed 100644 (file)
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,8 @@
+2020-06-11  Alan Modra  <amodra@gmail.com>
+
+       * elf/mips.h (Elf32_RegInfo): Use fixed width integer types.
+       (Elf64_Internal_RegInfo, Elf_Internal_Options): Likewise.
+
 2020-06-06  Alan Modra  <amodra@gmail.com>
 
        * elf/ppc64.h (elf_ppc64_reloc_type): Rename

diff --git a/include/elf/mips.h b/include/elf/mips.h
index d116b036b62574babbb3f097664174dba2f93461..cc08ebd4318106d9a8692be4a42538c9b4e85f87 100644 (file)
--- a/include/elf/mips.h
+++ b/include/elf/mips.h
@@ -560,11 +560,11 @@ typedef union
 typedef struct
 {
   /* Mask of general purpose registers used.  */
-  unsigned long ri_gprmask;
+  uint32_t ri_gprmask;
   /* Mask of co-processor registers used.  */
-  unsigned long ri_cprmask[4];
+  uint32_t ri_cprmask[4];
   /* GP register value for this object file.  */
-  long ri_gp_value;
+  uint32_t ri_gp_value;
 } Elf32_RegInfo;
 
 /* The external version of the Elf_RegInfo structure.  */
@@ -1008,9 +1008,9 @@ typedef struct
   /* Size of option descriptor, including header.  */
   unsigned char size;
   /* Section index of affected section, or 0 for global option.  */
-  unsigned short section;
+  uint16_t section;
   /* Information specific to this kind of option.  */
-  unsigned long info;
+  uint32_t info;
 } Elf_Internal_Options;
 
 /* MIPS ELF option header swapping routines.  */
@@ -1074,13 +1074,13 @@ typedef struct
 typedef struct
 {
   /* Mask of general purpose registers used.  */
-  unsigned long ri_gprmask;
+  uint32_t ri_gprmask;
   /* Padding.  */
-  unsigned long ri_pad;
+  uint32_t ri_pad;
   /* Mask of co-processor registers used.  */
-  unsigned long ri_cprmask[4];
+  uint32_t ri_cprmask[4];
   /* GP register value for this object file.  */
-  bfd_vma ri_gp_value;
+  uint64_t ri_gp_value;
 } Elf64_Internal_RegInfo;
 
 /* ABI Flags structure version 0.  */