From 717ba204e06d88ed68441e236da3688a92cf054c Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Tue, 21 Jun 2016 20:12:00 +0100 Subject: [PATCH] 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) : Avoid null pointer dereferences via `fixP->fx_addsy'. --- gas/ChangeLog | 6 ++++++ gas/config/tc-mips.c | 4 ++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/gas/ChangeLog b/gas/ChangeLog index 45a505434e7..6ccbaa24145 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,3 +1,9 @@ +2016-06-21 Maciej W. Rozycki + + * config/tc-mips.c (md_apply_fix) + : Avoid null pointer dereferences + via `fixP->fx_addsy'. + 2016-06-21 Maciej W. Rozycki * config/tc-mips.c (md_pcrel_from) : diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c index 74f7e005607..c598806b8f3 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; -- 2.30.2