[binutils-gdb] PR25662, invalid sh_offset for first section in segment with phdrs

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d16e3d2e5b717cf83c1fe47a70e0a9f2c2024a44

commit d16e3d2e5b717cf83c1fe47a70e0a9f2c2024a44
Author: Alan Modra <amodra@gmail.com>
Date:   Tue Mar 24 10:42:45 2020 +1030

    PR25662, invalid sh_offset for first section in segment with phdrs
    
            PR 25662
            * elf.c (assign_file_positions_for_load_sections): Adjust offset
            for SHT_NOBITS section if first in segment.

Diff:
---
 bfd/ChangeLog |  6 ++++++
 bfd/elf.c     | 22 +++++++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index f273ea54e9b..b4160c943a5 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-25  Alan Modra  <amodra@gmail.com>
+
+	PR 25662
+	* elf.c (assign_file_positions_for_load_sections): Adjust offset
+	for SHT_NOBITS section if first in segment.
+
 2020-03-24  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR binutils/25708
diff --git a/bfd/elf.c b/bfd/elf.c
index 2512b6543b1..86dadea05ca 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -5833,10 +5833,11 @@ assign_file_positions_for_load_sections (bfd *abfd,
 		}
 	      p->p_memsz += adjust;
 
-	      if (this_hdr->sh_type != SHT_NOBITS)
+	      if (p->p_type == PT_LOAD)
 		{
-		  if (p->p_type == PT_LOAD)
+		  if (this_hdr->sh_type != SHT_NOBITS)
 		    {
+		      off_adjust = 0;
 		      if (p->p_filesz + adjust < p->p_memsz)
 			{
 			  /* We have a PROGBITS section following NOBITS ones.
@@ -5846,10 +5847,25 @@ assign_file_positions_for_load_sections (bfd *abfd,
 			  if (!write_zeros (abfd, off, adjust))
 			    return FALSE;
 			}
+		    }
+		  /* We only adjust sh_offset in SHT_NOBITS sections
+		     as would seem proper for their address when the
+		     section is first in the segment.  sh_offset
+		     doesn't really have any significance for
+		     SHT_NOBITS anyway, apart from a notional position
+		     relative to other sections.  Historically we
+		     didn't bother with adjusting sh_offset and some
+		     programs depend on it not being adjusted.  See
+		     pr12921 and pr25662.  */
+		  if (this_hdr->sh_type != SHT_NOBITS || i == 0)
+		    {
 		      off += adjust;
+		      if (this_hdr->sh_type == SHT_NOBITS)
+			off_adjust += adjust;
 		    }
-		  p->p_filesz += adjust;
 		}
+	      if (this_hdr->sh_type != SHT_NOBITS)
+		p->p_filesz += adjust;
 	    }
 
 	  if (p->p_type == PT_NOTE && bfd_get_format (abfd) == bfd_core)