Re: Hardening

[ng0]

Alex Vong <address@hidden> writes:

> Hi,
>
> Wow, this was long time ago. I've forgot this completely.
>
> Ricardo Wurmus <address@hidden> writes:
>
>> Leo Famulari <address@hidden> writes:
>>
>>> On Wed, Dec 30, 2015 at 05:06:30PM +0100, Ludovic Courtès wrote:
>>>> Alex Vong <address@hidden> skribis:
>>>> > Yes, I grep for `fstack-protector-strong' in the guix code base and no
>>>> > matches are found. It appears no packages are setting this flag
>>>> > currently. I think this flag (perhaps also a couple others) should be
>>>> > set by default since they help protect against buffer overflow
>>>> > <https://en.wikipedia.org/wiki/Buffer_overflow_protection>.
>>>> 
>>>> I definitely agree, that’s something I’ve been wanting to try out.
>>>> 
>>>> The question is more how.  Do we change the default #:configure-flags
>>>> for ‘gnu-build-system’ to something like:
>>>> 
>>>>   '("CPPFLAGS=-D_FORTIFY_SOURCE=2"
>>>>     "CFLAGS=-O2 -g -fstack-protector-strong")
>>>> 
>>>> ?
>>>> 
>>>> That sounds like a good starting point, but I expect that (1) one third
>>>> of the packages will fail to build, and (2) another third of the
>>>> packages will not get these flags, for instance because they pass their
>>>> own #:configure-flags.
>>>> 
>>>> IOW, it will take a whole rebuild to find out exactly what’s going on
>>>> and to fix any issues.
>>>> 
>>>> Would you like to start working on it?  Then we could create a branch,
>>>> have Hydra build it, and incrementally fix things.
>>>
>>> We should pick this project back up. I was suprised to find we haven't
>>> done anything like this after reading this recent blog post about Nix's
>>> hardening effort:
>>>
>>> https://blog.mayflower.de/5800-Hardening-Compiler-Flags-for-NixOS.html?utm_source=twitterfeed&utm_medium=twitter
>>
>> Are the above flags the only flags we’d like to play with?  There’s no
>> harm in letting hydra rebuild the world with these flags on a separate
>> branch — provided that all build nodes are usable.
>>
> There are indeed additional flags (for debian's hardening).
>
>
> Here is the complete output (from the testing distribution):
>
> address@hidden:~$ DEB_BUILD_MAINT_OPTIONS=hardening=+all dpkg-buildflags
> CFLAGS=-g -O2 -fdebug-prefix-map=/home/alexvong1995=. -fPIE 
> -fstack-protector-strong -Wformat -Werror=format-security
> CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=2
> CXXFLAGS=-g -O2 -fdebug-prefix-map=/home/alexvong1995=. -fPIE 
> -fstack-protector-strong -Wformat -Werror=format-security
> FCFLAGS=-g -O2 -fdebug-prefix-map=/home/alexvong1995=. -fPIE 
> -fstack-protector-strong
> FFLAGS=-g -O2 -fdebug-prefix-map=/home/alexvong1995=. -fPIE 
> -fstack-protector-strong
> GCJFLAGS=-g -O2 -fdebug-prefix-map=/home/alexvong1995=. -fPIE 
> -fstack-protector-strong
> LDFLAGS=-fPIE -pie -Wl,-z,relro -Wl,-z,now
> OBJCFLAGS=-g -O2 -fdebug-prefix-map=/home/alexvong1995=. -fPIE 
> -fstack-protector-strong -Wformat -Werror=format-security
> OBJCXXFLAGS=-g -O2 -fdebug-prefix-map=/home/alexvong1995=. -fPIE 
> -fstack-protector-strong -Wformat -Werror=format-security
>
>
> The `-fdebug-prefix-map' flag seems to be using the current working
> directory.
>
>> ~~ Ricardo
>
> Cheers,
> Alex
>

I think there's even more, I can add to this thread when I have access
to my hardened vm systems again.

Good to see that this is being picked up again.
-- 
ng0
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