[binutils-gdb] opcodes: don't assume ELF in riscv, csky, rl78, mep disassemblers

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=16089f320a9226e7cdb73e9fb4266d9e450085b2

commit 16089f320a9226e7cdb73e9fb4266d9e450085b2
Author: Thomas Hebb <tommyhebb@gmail.com>
Date:   Fri Apr 29 21:17:58 2022 -0700

    opcodes: don't assume ELF in riscv, csky, rl78, mep disassemblers
    
    Currently, the get_disassembler() implementations for riscv, csky, and
    rl78--and mep_print_insn() for mep--access ELF variants of union fields
    without first checking that the bfd actually represents an ELF.  This
    causes undefined behavior and crashes when disassembling non-ELF files
    (the "binary" BFD, for example).  Fix that.

Diff:
---
 cpu/mep.opc         | 13 ++++++++-----
 opcodes/csky-dis.c  |  2 +-
 opcodes/mep-dis.c   | 13 ++++++++-----
 opcodes/riscv-dis.c | 28 ++++++++++++----------------
 opcodes/rl78-dis.c  |  2 +-
 5 files changed, 30 insertions(+), 28 deletions(-)

diff --git a/cpu/mep.opc b/cpu/mep.opc
index 6ad0c5879e8..278b4454c33 100644
--- a/cpu/mep.opc
+++ b/cpu/mep.opc
@@ -1451,12 +1451,15 @@ mep_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
   if (info->section && info->section->owner)
     {
       bfd *abfd = info->section->owner;
-      mep_config_index = abfd->tdata.elf_obj_data->elf_header->e_flags & EF_MEP_INDEX_MASK;
-      /* This instantly redefines MEP_CONFIG, MEP_OMASK, .... MEP_VLIW64 */
+      if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+	{
+	  mep_config_index = abfd->tdata.elf_obj_data->elf_header->e_flags & EF_MEP_INDEX_MASK;
+	  /* This instantly redefines MEP_CONFIG, MEP_OMASK, .... MEP_VLIW64 */
 
-      cop_type = abfd->tdata.elf_obj_data->elf_header->e_flags & EF_MEP_COP_MASK;
-      if (cop_type == EF_MEP_COP_IVC2)
-	ivc2 = 1;
+	  cop_type = abfd->tdata.elf_obj_data->elf_header->e_flags & EF_MEP_COP_MASK;
+	  if (cop_type == EF_MEP_COP_IVC2)
+	    ivc2 = 1;
+	}
     }
 
   /* Picking the right ISA bitmask for the current context is tricky.  */
diff --git a/opcodes/csky-dis.c b/opcodes/csky-dis.c
index 96163166fc3..b7c833623e5 100644
--- a/opcodes/csky-dis.c
+++ b/opcodes/csky-dis.c
@@ -239,7 +239,7 @@ csky_get_disassembler (bfd *abfd)
 {
   obj_attribute *attr;
   const char *sec_name = NULL;
-  if (!abfd)
+  if (!abfd || bfd_get_flavour (abfd) != bfd_target_elf_flavour)
     dis_info.isa = CSKY_DEFAULT_ISA;
   else
     {
diff --git a/opcodes/mep-dis.c b/opcodes/mep-dis.c
index 188ee298202..c56e90dcc6f 100644
--- a/opcodes/mep-dis.c
+++ b/opcodes/mep-dis.c
@@ -647,12 +647,15 @@ mep_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
   if (info->section && info->section->owner)
     {
       bfd *abfd = info->section->owner;
-      mep_config_index = abfd->tdata.elf_obj_data->elf_header->e_flags & EF_MEP_INDEX_MASK;
-      /* This instantly redefines MEP_CONFIG, MEP_OMASK, .... MEP_VLIW64 */
+      if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+	{
+	  mep_config_index = abfd->tdata.elf_obj_data->elf_header->e_flags & EF_MEP_INDEX_MASK;
+	  /* This instantly redefines MEP_CONFIG, MEP_OMASK, .... MEP_VLIW64 */
 
-      cop_type = abfd->tdata.elf_obj_data->elf_header->e_flags & EF_MEP_COP_MASK;
-      if (cop_type == EF_MEP_COP_IVC2)
-	ivc2 = 1;
+	  cop_type = abfd->tdata.elf_obj_data->elf_header->e_flags & EF_MEP_COP_MASK;
+	  if (cop_type == EF_MEP_COP_IVC2)
+	    ivc2 = 1;
+	}
     }
 
   /* Picking the right ISA bitmask for the current context is tricky.  */
diff --git a/opcodes/riscv-dis.c b/opcodes/riscv-dis.c
index bfaefa3fb47..9ff31167775 100644
--- a/opcodes/riscv-dis.c
+++ b/opcodes/riscv-dis.c
@@ -1002,24 +1002,20 @@ riscv_get_disassembler (bfd *abfd)
 {
   const char *default_arch = "rv64gc";
 
-  if (abfd)
+  if (abfd && bfd_get_flavour (abfd) == bfd_target_elf_flavour)
     {
-      const struct elf_backend_data *ebd = get_elf_backend_data (abfd);
-      if (ebd)
+      const char *sec_name = get_elf_backend_data (abfd)->obj_attrs_section;
+      if (bfd_get_section_by_name (abfd, sec_name) != NULL)
 	{
-	  const char *sec_name = ebd->obj_attrs_section;
-	  if (bfd_get_section_by_name (abfd, sec_name) != NULL)
-	    {
-	      obj_attribute *attr = elf_known_obj_attributes_proc (abfd);
-	      unsigned int Tag_a = Tag_RISCV_priv_spec;
-	      unsigned int Tag_b = Tag_RISCV_priv_spec_minor;
-	      unsigned int Tag_c = Tag_RISCV_priv_spec_revision;
-	      riscv_get_priv_spec_class_from_numbers (attr[Tag_a].i,
-						      attr[Tag_b].i,
-						      attr[Tag_c].i,
-						      &default_priv_spec);
-	      default_arch = attr[Tag_RISCV_arch].s;
-	    }
+	  obj_attribute *attr = elf_known_obj_attributes_proc (abfd);
+	  unsigned int Tag_a = Tag_RISCV_priv_spec;
+	  unsigned int Tag_b = Tag_RISCV_priv_spec_minor;
+	  unsigned int Tag_c = Tag_RISCV_priv_spec_revision;
+	  riscv_get_priv_spec_class_from_numbers (attr[Tag_a].i,
+						  attr[Tag_b].i,
+						  attr[Tag_c].i,
+						  &default_priv_spec);
+	  default_arch = attr[Tag_RISCV_arch].s;
 	}
     }
 
diff --git a/opcodes/rl78-dis.c b/opcodes/rl78-dis.c
index cc08a298688..2d7ffb26eba 100644
--- a/opcodes/rl78-dis.c
+++ b/opcodes/rl78-dis.c
@@ -408,7 +408,7 @@ rl78_get_disassembler (bfd *abfd)
 {
   int cpu = E_FLAG_RL78_ANY_CPU;
 
-  if (abfd != NULL)
+  if (abfd != NULL && bfd_get_flavour (abfd) == bfd_target_elf_flavour)
     cpu = abfd->tdata.elf_obj_data->elf_header->e_flags & E_FLAG_RL78_CPU_MASK;
 
   switch (cpu)