1417452 - glibc-2.25 prevents building with _FORTIFY_SOURCE without any optimization level.

Status: RESOLVED FIXED

(Core :: Security, enhancement)

Description

[Nicolas B. Pierron [:nbp]]

glibc-2.25-dev/include/features.h:
> 
> #if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0
> # if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0
> #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
> # elif !__GNUC_PREREQ (4, 1)
> #  warning _FORTIFY_SOURCE requires GCC 4.1 or later
> # elif _FORTIFY_SOURCE > 1
> #  define __USE_FORTIFY_LEVEL 2
> # else
> #  define __USE_FORTIFY_LEVEL 1
> # endif
> #endif
> #ifndef __USE_FORTIFY_LEVEL
> # define __USE_FORTIFY_LEVEL 0
> #endif
>

Comment 1

[Nicolas B. Pierron [:nbp]]

Attachment: Disable FORTIFY_SOURCE if hardening flags are disabled.

This patch adds a way to disable FORTIFY_SOURCE macro definition from the
command line if there is no other hardening flags defined.

This patch enable us to compile with --enable-debug, by setting --disable-hardening.

Comment 2

[Nathan Froyd [:froydnj]]

Why is --enable-debug a problem?  Do you mean --enable-debug --disable-optimize?

I'm not sure that conditioning this on hardening flags is really the right thing.

Comment 3

[Tom Ritter [:tjr] (OOTO until 4/30 at least)]

I think we should make --disable-hardening turn off FORTIFY_SOURCE.

But I am not sure we want to require --disable-hardening to be added by users affected by this. It seems like we should make the build 'just work' and not require unexpected flags. 

I suppose the best way to do that is to detect the optimization level and not add FORTIFY_SOURCE if it is not set? Although the drawbacks of that would be that we will disable it in places we don't need to (I have to assume not every libc (or glibc version) is affected by this, since try was not) - and if we tried to be smarter I'm not sure we have the libc package name or version in old-configure...

Comment 4

[Nicolas B. Pierron [:nbp]]

(In reply to Nathan Froyd [:froydnj] from comment #2)
> Why is --enable-debug a problem?  Do you mean --enable-debug
> --disable-optimize?

Yes, this is what I meant. Sorry about the lack of --disable-optimize.

Comment 5

[Jim Blandy :jimb]

(In reply to Tom Ritter [:tjr] from comment #3)
> I think we should make --disable-hardening turn off FORTIFY_SOURCE.
> 
> ... It seems like we should make the build 'just work'
> and not require unexpected flags. 
> 
> I suppose the best way to do that is to detect the optimization level and
> not add FORTIFY_SOURCE if it is not set?

This would be my favorite solution. Unoptimized builds are slow enough that we will always have enough optimized builds around to catch things, so I'm not worried about the coverage.

Comment 6

[Tom Ritter [:tjr] (OOTO until 4/30 at least)]

I'm going to flag :glandium to see what he thinks, I feel like he may have a good POV on how to proceed.

Comment 7

[Mike Hommey [:glandium]]

Considering glibc's features.h, the right thing to do would be to disable FORTIFY_SOURCE with --disable-optimize.

Comment 8

[Tom Ritter [:tjr] (OOTO until 4/30 at least)]

Attachment: Bug 1417452 Do not add FORTIFY_SOURCE if --enable-optimize is not set

Review commit: https://reviewboard.mozilla.org/r/200434/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/200434/

Comment 9

[Tom Ritter [:tjr] (OOTO until 4/30 at least)]

I broke out Bug 1418052 to get this one fixed earlier and because that one is a bit more complicated

Comment 10

[Mike Hommey [:glandium]]

Comment on attachment 8929142 [details]
Bug 1417452 Do not add FORTIFY_SOURCE if --enable-optimize is not set

https://reviewboard.mozilla.org/r/200434/#review205710

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/59e899eba461
Do not add FORTIFY_SOURCE if --enable-optimize is not set r=glandium

Comment 12

[Gabriele Svelto [:gsvelto] (PTO)]

I've just bumped into a similar issue on Gentoo where GCC defines _FORTIFY_SOURCE as a built-in, see bug 1418398.

Comment 13

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/59e899eba461