[binutils-gdb] x86: reject relocations involving registers

[Jan Beulich]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=e52a16f2aa20773f42c28bf91a568d0683e5767c

commit e52a16f2aa20773f42c28bf91a568d0683e5767c
Author: Jan Beulich <jbeulich@suse.com>
Date:   Wed Mar 23 12:31:29 2022 +0100

    x86: reject relocations involving registers
    
    To prevent fatal or even internal errors, add a simple check to
    i386_validate_fix(), rejecting relocations when their target symbol is
    an equate of a register (or resolved to reg_section for any other
    reason).

Diff:
---
 gas/config/tc-i386.c                 | 11 +++++++++++
 gas/testsuite/gas/i386/inval-equ-2.l |  6 ++++++
 2 files changed, 17 insertions(+)

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 93eec1c9ed4..76177924d39 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -14188,6 +14188,17 @@ i386_cons_align (int ignore ATTRIBUTE_UNUSED)
 int
 i386_validate_fix (fixS *fixp)
 {
+  if (fixp->fx_addsy && S_GET_SEGMENT(fixp->fx_addsy) == reg_section)
+    {
+      reloc_howto_type *howto;
+
+      howto = bfd_reloc_type_lookup (stdoutput, fixp->fx_r_type);
+      as_bad_where (fixp->fx_file, fixp->fx_line,
+		    _("invalid %s relocation against register"),
+		    howto ? howto->name : "<unknown>");
+      return 0;
+    }
+
 #if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
   if (fixp->fx_r_type == BFD_RELOC_SIZE32
       || fixp->fx_r_type == BFD_RELOC_SIZE64)
diff --git a/gas/testsuite/gas/i386/inval-equ-2.l b/gas/testsuite/gas/i386/inval-equ-2.l
index 11f5e4ed3e9..839bc8d3523 100644
--- a/gas/testsuite/gas/i386/inval-equ-2.l
+++ b/gas/testsuite/gas/i386/inval-equ-2.l
@@ -1,4 +1,7 @@
 .*: Assembler messages:
+.*:3: Error: .*
+.*:5: Error: .*
+.*:8: Error: .*
 .*: Error: .*
 .*: Error: .*
 .*: Error: .*
@@ -15,6 +18,9 @@ GAS LISTING .*
 [ 	]*6[ 	]+\.globl  bar2
 [ 	]*7[ 	]+\.set    bar3,\(%eax\+1\)
 [ 	]*8[ 	]+\?\?\?\? A1...... 		mov bar3,%eax
+.*  Error: invalid .* relocation against register
+.*  Error: invalid .* relocation against register
+.*  Error: invalid .* relocation against register
 .*  Error: can't make global register symbol `bar1'
 .*  Error: can't make global register symbol `bar2'
 .*  Error: can't make global register symbol `bar3'