[binutils-gdb] RISC-V: Fix linker crash in section symbol check.

[Jim Wilson]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=a9f5a5517fb7df640f0fcd4cb0f9961818b6505b

commit a9f5a5517fb7df640f0fcd4cb0f9961818b6505b
Author: Jim Wilson <jimw@sifive.com>
Date:   Thu Mar 21 15:08:48 2019 -0700

    RISC-V: Fix linker crash in section symbol check.
    
    sym is only set for local symbols.  h is only set for global symbols.  Gas
    won't let me create a global section symbol, but bfd appears to have some
    support for that, and I can't rule out that other assemblers might do this.
    So we need to support both, and verify sym and h are non-NULL before using.
    
    	bfd/
    	PR 24365
    	* elfnn-riscv.c (riscv_elf_relocate_section): For STT_SECTION check,
    	verify sym non-NULL before using.  Add identical check using h.

Diff:
---
 bfd/ChangeLog     | 6 ++++++
 bfd/elfnn-riscv.c | 4 +++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 31ffadf..1225e3c 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2019-03-21  Jim Wilson  <jimw@sifive.com>
+
+	PR 24365
+	* elfnn-riscv.c (riscv_elf_relocate_section): For STT_SECTION check,
+	verify sym non-NULL before using.  Add identical check using h.
+
 2019-03-21  Sudakshina Das  <sudi.das@arm.com>
 
 	* elf-bfd.h (struct elf_backend_data): Add argument to
diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
index 0a0ceb7..bb114e5 100644
--- a/bfd/elfnn-riscv.c
+++ b/bfd/elfnn-riscv.c
@@ -2059,7 +2059,9 @@ riscv_elf_relocate_section (bfd *output_bfd,
 	     all relocs to update these addends.  This is also ambiguous, as
 	     we do allow offsets to be added to the target address, which are
 	     not to be used to find the auipc address.  */
-	  if ((ELF_ST_TYPE (sym->st_info) == STT_SECTION) && rel->r_addend)
+	  if (((sym != NULL && (ELF_ST_TYPE (sym->st_info) == STT_SECTION))
+	       || (h != NULL && h->type == STT_SECTION))
+	      && rel->r_addend)
 	    {
 	      r = bfd_reloc_dangerous;
 	      break;