This is the mail archive of the
glibc-bugs@sourceware.org
mailing list for the glibc project.
[Bug dynamic-link/22370] Incorrect note padding check
- From: "cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sourceware dot org
- Date: Sat, 25 Nov 2017 14:34:16 +0000
- Subject: [Bug dynamic-link/22370] Incorrect note padding check
- Auto-submitted: auto-generated
- References: <bug-22370-131@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=22370
--- Comment #6 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".
The branch, hjl/pr22370/master has been created
at b7cfacca88269901546529445f0bb757107984b4 (commit)
- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b7cfacca88269901546529445f0bb757107984b4
commit b7cfacca88269901546529445f0bb757107984b4
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Tue Oct 31 04:51:41 2017 -0700
Properly compute offsets of note descriptor and next note [BZ #22370]
A note header has 3 4-bytes fields, followed by note name and note
descriptor. According to gABI, in a note entry, the note name field,
not note name size, is padded for the note descriptor. And the note
descriptor field, not note descriptor size, is padded for the next
note entry. Notes are aligned to 4 bytes in 32-bit objects and 8 bytes
in 64-bit objects.
For all GNU notes, the name is "GNU" which is 4 bytes. They have the
same format in the first 16 bytes in both 32-bit and 64-bit objects.
They differ by note descriptor size and note type. So far, .note.ABI-tag
and .note.gnu.build-id notes are always aligned to 4 bytes. The exsting
codes compute the note size by aligning the note name size and note
descriptor size to 4 bytes. It happens to produce the same value as
the actual note size by luck since the name size is 4 and offset of the
note descriptor is 16. But it will produce the wrong size when note
alignment is 8 bytes in 64-bit objects.
This patch defines ELF_NOTE_DESC_OFFSET and ELF_NOTE_NEXT_OFFSET to
properly compute offsets of note descriptor and next note. It uses
alignment of PT_NOTE segment to support both 4-byte and 8-byte note
alignments in 64-bit objects. To handle PT_NOTE segments with
incorrect alignment, which may lead to an infinite loop, if segment
alignment is less than 4, we treate alignment as 4 bytes.
[BZ #22370]
* elf/dl-hwcaps.c (ROUND): Removed.
(_dl_important_hwcaps): Replace ROUND with ELF_NOTE_DESC_OFFSET
and ELF_NOTE_NEXT_OFFSET.
* elf/dl-load.c (ROUND): Removed.
(open_verify): Replace ROUND with ELF_NOTE_NEXT_OFFSET.
* elf/readelflib.c (ROUND): Removed.
(process_elf_file): Replace ROUND with ELF_NOTE_NEXT_OFFSET.
* include/elf.h [!_ISOMAC]: Include <libc-pointer-arith.h>.
[!_ISOMAC] (ELF_NOTE_DESC_OFFSET): New.
[!_ISOMAC] (ELF_NOTE_NEXT_OFFSET): Likewise.
-----------------------------------------------------------------------
--
You are receiving this mail because:
You are on the CC list for the bug.