x86/Intel: don't accept bogus instructions

... due to their last byte looking like a suffix, when after its
stripping a matching instruction can be found. Since memory operand
size specifiers in Intel mode get converted into suffix representation
internally, we need to keep track of the actual mnemonic suffix which
may have got trimmed off, and check its validity while looking for a
matching template. I tripper over this quite some time again after
support for AMD's SSE5 instructions got removed, as at that point some
of the SSE5 mnemonics, other than expected, didn't fail to assemble.
But the problem affects many more instructions, namely (almost) all
MMX, SSE, and AVX ones as it looks. I don't think it makes sense to
add a testcase covering all of them, nor do I think it makes sense to
pick out some random examples for a new test case.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index db25ef2e73daa6854e066cb09b1d3c52886e08d8..2e14703bc3ee15a63d4d67d07951a03a5b8f6042 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,13 @@
+2016-07-01  Jan Beulich  <jbeulich@suse.com>
+
+       PR gas/20318
+       * config/tc-i386.c (match_template): Add char parameter,
+       consumed in Intel mode for an extra suffix check.
+       (md_assemble): New local variable mnem_suffix.
+       * testsuite/gas/i386/suffix-bad.s: New.
+       * testsuite/gas/i386/suffix-bad.l: New.
+       * testsuite/gas/i386/i386.exp: Run new test (twice).
+
 2016-07-01  Jan Beulich  <jbeulich@suse.com>
 
        * testsuite/gas/i386/movz.s: New.

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index d85dcd903901f29e338a87e3dc47a93706263409..9f1b7f0ce2fba0ace56eecf8e261719ee452b694 100644 (file)
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -173,7 +173,7 @@ static void swap_operands (void);
 static void swap_2_operands (int, int);
 static void optimize_imm (void);
 static void optimize_disp (void);
-static const insn_template *match_template (void);
+static const insn_template *match_template (char);
 static int check_string (void);
 static int process_suffix (void);
 static int check_byte_reg (void);
@@ -3537,7 +3537,7 @@ void
 md_assemble (char *line)
 {
   unsigned int j;
-  char mnemonic[MAX_MNEM_SIZE];
+  char mnemonic[MAX_MNEM_SIZE], mnem_suffix;
   const insn_template *t;
 
   /* Initialize globals.  */
@@ -3555,6 +3555,7 @@ md_assemble (char *line)
   line = parse_insn (line, mnemonic);
   if (line == NULL)
     return;
+  mnem_suffix = i.suffix;
 
   line = parse_operands (line, mnemonic);
   this_operand = -1;
@@ -3600,7 +3601,7 @@ md_assemble (char *line)
      making sure the overlap of the given operands types is consistent
      with the template operand types.  */
 
-  if (!(t = match_template ()))
+  if (!(t = match_template (mnem_suffix)))
     return;
 
   if (sse_check != check_none
@@ -4724,14 +4725,14 @@ VEX_check_operands (const insn_template *t)
 }
 
 static const insn_template *
-match_template (void)
+match_template (char mnem_suffix)
 {
   /* Points to template once we've found it.  */
   const insn_template *t;
   i386_operand_type overlap0, overlap1, overlap2, overlap3;
   i386_operand_type overlap4;
   unsigned int found_reverse_match;
-  i386_opcode_modifier suffix_check;
+  i386_opcode_modifier suffix_check, mnemsuf_check;
   i386_operand_type operand_types [MAX_OPERANDS];
   int addr_prefix_disp;
   unsigned int j;
@@ -4760,6 +4761,19 @@ match_template (void)
   else if (i.suffix == LONG_DOUBLE_MNEM_SUFFIX)
     suffix_check.no_ldsuf = 1;
 
+  memset (&mnemsuf_check, 0, sizeof (mnemsuf_check));
+  if (intel_syntax)
+    {
+      switch (mnem_suffix)
+       {
+       case BYTE_MNEM_SUFFIX:  mnemsuf_check.no_bsuf = 1; break;
+       case WORD_MNEM_SUFFIX:  mnemsuf_check.no_wsuf = 1; break;
+       case SHORT_MNEM_SUFFIX: mnemsuf_check.no_ssuf = 1; break;
+       case LONG_MNEM_SUFFIX:  mnemsuf_check.no_lsuf = 1; break;
+       case QWORD_MNEM_SUFFIX: mnemsuf_check.no_qsuf = 1; break;
+       }
+    }
+
   /* Must have right number of operands.  */
   i.error = number_of_operands_mismatch;
 
@@ -4805,6 +4819,14 @@ match_template (void)
              || (t->opcode_modifier.no_qsuf && suffix_check.no_qsuf)
              || (t->opcode_modifier.no_ldsuf && suffix_check.no_ldsuf)))
        continue;
+      /* In Intel mode all mnemonic suffixes must be explicitly allowed.  */
+      if ((t->opcode_modifier.no_bsuf && mnemsuf_check.no_bsuf)
+         || (t->opcode_modifier.no_wsuf && mnemsuf_check.no_wsuf)
+         || (t->opcode_modifier.no_lsuf && mnemsuf_check.no_lsuf)
+         || (t->opcode_modifier.no_ssuf && mnemsuf_check.no_ssuf)
+         || (t->opcode_modifier.no_qsuf && mnemsuf_check.no_qsuf)
+         || (t->opcode_modifier.no_ldsuf && mnemsuf_check.no_ldsuf))
+       continue;
 
       if (!operand_size_match (t))
        continue;

diff --git a/gas/testsuite/gas/i386/i386.exp b/gas/testsuite/gas/i386/i386.exp
index 871004bcb1cf3b25a37c6d3b5e4c28aabd67426b..6e002627f0033105ae9e6750b2883201fe8ad4cc 100644 (file)
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@@ -76,6 +76,7 @@ if [expr ([istarget "i*86-*-*"] ||  [istarget "x86_64-*-*"]) && [gas_32_check]]
     run_dump_test "smx"
     run_dump_test "suffix"
     run_dump_test "suffix-intel"
+    run_list_test "suffix-bad"
     run_dump_test "immed32"
     run_dump_test "equ"
     run_dump_test "divide"
@@ -571,6 +572,7 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_64_check]] t
     run_dump_test "x86-64-disp32"
     run_dump_test "rexw"
     run_list_test "x86-64-specific-reg"
+    run_list_test "suffix-bad"
     run_list_test "x86-64-suffix-bad"
     run_dump_test "x86-64-fxsave"
     run_dump_test "x86-64-fxsave-intel"

diff --git a/gas/testsuite/gas/i386/suffix-bad.l b/gas/testsuite/gas/i386/suffix-bad.l
new file mode 100644 (file)
index 0000000..10868c3
--- /dev/null
+++ b/gas/testsuite/gas/i386/suffix-bad.l
@@ -0,0 +1,15 @@
+.*: Assembler messages:
+.*:3: Error: .*
+.*:4: Error: .*
+.*:5: Error: .*
+.*:6: Error: .*
+.*:7: Error: .*
+.*:8: Error: .*
+.*:9: Error: .*
+.*:12: Error: .*
+.*:13: Error: .*
+.*:14: Error: .*
+.*:15: Error: .*
+.*:16: Error: .*
+.*:17: Error: .*
+.*:18: Error: .*

diff --git a/gas/testsuite/gas/i386/suffix-bad.s b/gas/testsuite/gas/i386/suffix-bad.s
new file mode 100644 (file)
index 0000000..fceffe9
--- /dev/null
+++ b/gas/testsuite/gas/i386/suffix-bad.s
@@ -0,0 +1,18 @@
+       .text
+suffix:
+       phadddb %xmm0, %xmm1
+       phadddd %xmm0, %xmm1
+       phadddl %xmm0, %xmm1
+       phadddld %xmm0, %xmm1
+       phadddq %xmm0, %xmm1
+       phaddds %xmm0, %xmm1
+       phadddw %xmm0, %xmm1
+
+       .intel_syntax noprefix
+       phadddb xmm0, xmm1
+       phadddd xmm0, xmm1
+       phadddl xmm0, xmm1
+       phadddld xmm0, xmm1
+       phadddq xmm0, xmm1
+       phaddds xmm0, xmm1
+       phadddw xmm0, xmm1