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[v4,0/2] _FORTIFY_SOURCE=3

Message ID 20201215182238.2780547-1-siddhesh@sourceware.org
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Series _FORTIFY_SOURCE=3 | expand

Message

Siddhesh Poyarekar Dec. 15, 2020, 6:22 p.m. UTC 
Posting the full series again with fixes for convenience.  Since the
patches were deemed OK with some cosmetic change suggestions, I'll
commit this series by the end of the week if there are no further
comments.

-------------

This patchset implements a new fortification level, _FORTIFY_SOURCE=3.
This level allows size information to be dynamic, which may potentially
have a noticeable performance impact.  It uses the
__builtin_dynamic_object_size builtin available in clang to expand
coverage of fortifications at the expense of some performance.

Patch 1/2 implements the base support and support for functions that
have builtins of string functions.  Additionally, the patch also
describes the use case and tradeoffs.

Patch 2/2 adds support for non-string functions that are
fortification-ready for levels 1 and 2.

Testing:

The glibc testsuite doesn't directly support clang at the moment, so
having tests in the glibc source tree is pointless as long as gcc does
not have support for __builtin_dynamic_object_size.  There is a separate
project on GitHub called fortify-test-suite[1] that houses fortification
tests and is capable of testing multiple levels of fortification with
multiple compilers.  I have proposed a PR[2] to add support for
_FORTIFY_SOURCE=3 and have verified my changes with those tests.

Those tests run clean for clang when run with these changes and PR[2]
and they fail at level 3 for gcc, as expected.

[1] https://github.com/serge-sans-paille/fortify-test-suite
[2] https://github.com/serge-sans-paille/fortify-test-suite/pull/9

Changes from previous series:

- Incorporated NEWS and creature.texi wording change suggestions
- Fixed comment in 2/2.

Siddhesh Poyarekar (2):
  string: _FORTIFY_SOURCE=3 using __builtin_dynamic_object_size
  nonstring: _FORTIFY_SOURCE=3 using __builtin_dynamic_object_size

 NEWS                            |   6 ++
 include/features.h              |  11 ++-
 include/string.h                |   5 +-
 io/bits/poll2.h                 |  16 ++--
 libio/bits/stdio.h              |   2 +-
 libio/bits/stdio2.h             |  53 ++++++-------
 manual/creature.texi            |   3 +-
 misc/sys/cdefs.h                |   9 +++
 posix/bits/unistd.h             | 112 ++++++++++++++-------------
 socket/bits/socket2.h           |  18 ++---
 stdlib/bits/stdlib.h            |  37 ++++-----
 string/bits/string_fortified.h  |  22 +++---
 string/bits/strings_fortified.h |   4 +-
 wcsmbs/bits/wchar2.h            | 131 ++++++++++++++++----------------
 14 files changed, 231 insertions(+), 198 deletions(-)