From: Maciej W. Rozycki <macro@imgtec.com>
Date: Tue, 21 Jun 2016 19:12:00 +0000 (+0100)
Subject: MIPS/GAS: Fix null pointer dereferences in R6 PC-relative relocation checks
X-Git-Tag: binutils-2_27~147
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=717ba204e06d88ed68441e236da3688a92cf054c;p=external%2Fbinutils.git

MIPS/GAS: Fix null pointer dereferences in R6 PC-relative relocation checks

Avoid segmentation faults in alignment checks made in `md_apply_fix' for
BFD_RELOC_MIPS_18_PCREL_S3 and BFD_RELOC_MIPS_19_PCREL_S2 relocations
caused by dereferencing `fixP->fx_addsy' which will be null if the
relocation processed has been fully resolved.

	gas/
	* config/tc-mips.c (md_apply_fix) <BFD_RELOC_MIPS_18_PCREL_S3>
	<BFD_RELOC_MIPS_19_PCREL_S2>: Avoid null pointer dereferences
	via `fixP->fx_addsy'.
---

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 45a5054..6ccbaa2 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,5 +1,11 @@
 2016-06-21  Maciej W. Rozycki  <macro@imgtec.com>
 
+	* config/tc-mips.c (md_apply_fix) <BFD_RELOC_MIPS_18_PCREL_S3>
+	<BFD_RELOC_MIPS_19_PCREL_S2>: Avoid null pointer dereferences
+	via `fixP->fx_addsy'.
+
+2016-06-21  Maciej W. Rozycki  <macro@imgtec.com>
+
 	* config/tc-mips.c (md_pcrel_from) <BFD_RELOC_MIPS_18_PCREL_S3>:
 	Calculate relocation from the containing aligned doubleword.
 	(tc_gen_reloc) <BFD_RELOC_MIPS_18_PCREL_S3>: Calculate the
diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
index 74f7e00..c598806 100644
--- a/gas/config/tc-mips.c
+++ b/gas/config/tc-mips.c
@@ -15034,7 +15034,7 @@ md_apply_fix (fixS *fixP, valueT *valP, segT seg ATTRIBUTE_UNUSED)
       break;
 
     case BFD_RELOC_MIPS_18_PCREL_S3:
-      if ((S_GET_VALUE (fixP->fx_addsy) & 0x7) != 0)
+      if (fixP->fx_addsy && (S_GET_VALUE (fixP->fx_addsy) & 0x7) != 0)
 	as_bad_where (fixP->fx_file, fixP->fx_line,
 		      _("PC-relative access using misaligned symbol (%lx)"),
 		      (long) S_GET_VALUE (fixP->fx_addsy));
@@ -15050,7 +15050,7 @@ md_apply_fix (fixS *fixP, valueT *valP, segT seg ATTRIBUTE_UNUSED)
       if ((*valP & 0x3) != 0)
 	as_bad_where (fixP->fx_file, fixP->fx_line,
 		      _("PC-relative access to misaligned address (%lx)"),
-		      (long) (S_GET_VALUE (fixP->fx_addsy) + fixP->fx_offset));
+		      (long) *valP);
 
       gas_assert (!fixP->fx_done);
       break;