[PATCH v5 0/2] _FORTIFY_SOURCE=3
Siddhesh Poyarekar
siddhesh@sourceware.org
Wed Dec 16 15:24:08 GMT 2020
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:
- Updated the _FORTIFY_SOURCE macro soup to warn on invalid values to
_FORTIFY_SOURCE with an indication of what level was chosen.
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, 233 insertions(+), 196 deletions(-)
--
2.29.2
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