From 4ffd290906608e72fd98d627a24aa2c2b6ecf4ce Mon Sep 17 00:00:00 2001 From: Tamar Christina Date: Fri, 1 Mar 2019 11:37:51 +0000 Subject: [PATCH] Binutils: Always skip only 1 byte for CIE version 1's return address register. According to the specification for the CIE entries, when the CIE version is 1 then the return address register field is always 1 byte. Readelf does this correctly in read_cie in dwarf.c but ld does this incorrectly and always tries to read a skip_leb128. If the value here has the top bit set then ld will incorrectly read at least another byte, causing either an assert failure or an incorrect address to be used in eh_frame. I'm not sure how to generate a generic test for this as I'd need to write assembly, and it's a bit hard to trigger. Essentially the relocated value needs to start with something that & 0x70 != 0x10 while trying to write a personality. bfd/ChangeLog: * elf-eh-frame.c (_bfd_elf_write_section_eh_frame): Correct CIE parse. --- bfd/ChangeLog | 4 ++++ bfd/elf-eh-frame.c | 12 ++++++++---- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 100c453eae7..68004eab088 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,7 @@ +2019-02-28 Tamar Christina + + * elf-eh-frame.c (_bfd_elf_write_section_eh_frame): Correct CIE parse. + 2019-02-28 Nick Clifton PR 24273 diff --git a/bfd/elf-eh-frame.c b/bfd/elf-eh-frame.c index a13e81ebb86..6919ac3031b 100644 --- a/bfd/elf-eh-frame.c +++ b/bfd/elf-eh-frame.c @@ -1993,7 +1993,7 @@ _bfd_elf_write_section_eh_frame (bfd *abfd, || ent->u.cie.per_encoding_relative) { char *aug; - unsigned int action, extra_string, extra_data; + unsigned int version, action, extra_string, extra_data; unsigned int per_width, per_encoding; /* Need to find 'R' or 'L' augmentation's argument and modify @@ -2004,13 +2004,17 @@ _bfd_elf_write_section_eh_frame (bfd *abfd, extra_string = extra_augmentation_string_bytes (ent); extra_data = extra_augmentation_data_bytes (ent); - /* Skip length, id and version. */ - buf += 9; + /* Skip length, id. */ + buf += 8; + version = *buf++; aug = (char *) buf; buf += strlen (aug) + 1; skip_leb128 (&buf, end); skip_leb128 (&buf, end); - skip_leb128 (&buf, end); + if (version == 1) + skip_bytes (&buf, end, 1); + else + skip_leb128 (&buf, end); if (*aug == 'z') { /* The uleb128 will always be a single byte for the kind -- 2.30.2