adding support for hardened toolchain
Thu Jan 6 14:04:00 GMT 2011
On Thu, Dec 30, 2010 at 08:20:22AM -0600, Heiko Zuerker wrote:
> The hardened toolchain is not anything folks would look at on their
> own usually. Adding it to ct-ng would give it more exposure and more
> folks may tend to try it out. We really need to get to a place where
> things get more secure for everybody.
I agree on that, and thank you for bringing up this issue.
I've briefly looked at those patches and have a few comments.
My primary targets are lowly embedded systems, mostly ARM based.
- There seems to be no clear information about the downsides
of the hardening patches, e.g. wrt code size and performance
How about binary compatibility between hardened and unhardened
- Can the hardened toolchain build kernels? E.g. ARM support
for -fstack-protector was added in 2.6.35 c743f38013aeff58ef6252601e397b5ba281c633,
I have no idea about other architiectures.
- Do the PIE + RELRO changes work with uClibc?
- gcc-4.4.5-fortify_source-1.patch mixes three changes
in one patch:
1. -D_FORTIFY_SOURCE=2 default
2. "always overflow error"
3. some unspcified changes in libjava/java/lang/natClass.cc
I like 1., but 2. is an ugly hack (using getenv() to disable
the error), and 3. is unclear to me
- gcc-4.4.5-fpie-1.patch mixes:
1. -fPIE default
2. RELRO default
I think 1. is good (although it defeats prelink, http://lwn.net/Articles/190495/),
but 2. impacts startup time due to BIND_NOW; not sure about 3.
- gcc-4.4.5-fstack_protector-1.patch looks good
I think the patches might need to be split, and there should
be a config option for each patch which spells out the upsides
and downsides in the help text so the user has all the information
to make the right choice.
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