Disable _FORTIFY_SOURCE when enable-debug #17033

1. 
   achow101 commented at 11:58 PM on October 2, 2019: member

   The _FORTIFY_SOURCE macro is enabled by default when hardening is enabled, but it requires optimization in order to be used. Since we disable all optimization with --enable-debug, this macro doesn't actually do anything and instead just causes a lot of warnings to be printed. This PR explicitly disables _FORTIFY_SOURCE so that these useless warnings aren't printed.

2. fanquake added the label Build system on Oct 3, 2019
3. 
   laanwj commented at 3:00 AM on October 3, 2019: member

   I disagree with this, hardening should never be automatically disabled. Things such as stack cookies do not interfere with debugging at all, and if they do that's a bug that needs to be solved, it should be the default to debug as closely to the original code as possible.

   If this particular hardening feature really interferes with debugging then disable that, not all hardening features.

4. achow101 force-pushed on Oct 3, 2019
5. achow101 renamed this:
   Disable hardening when enable-debug
   Disable _FORTIFY_SOURCE when enable-debug
   on Oct 3, 2019
6. 
   achow101 commented at 4:16 PM on October 3, 2019: member

   I've changed this to just disable _FORTIFY_SOURCE when --enable-debug. It appears that it doesn't do anything with optimization level 0 (as we do for --enable-debug) except print that warning.

7. in configure.ac:755 in 637df834b8 outdated

    748 | @@ -749,12 +749,14 @@ if test x$use_hardening != xno; then
    749 |    AX_CHECK_COMPILE_FLAG([-Wstack-protector],[HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -Wstack-protector"])
    750 |    AX_CHECK_COMPILE_FLAG([-fstack-protector-all],[HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -fstack-protector-all"])
    751 |  
    752 | -  AX_CHECK_PREPROC_FLAG([-D_FORTIFY_SOURCE=2],[
    753 | -    AX_CHECK_PREPROC_FLAG([-U_FORTIFY_SOURCE],[
    754 | -      HARDENED_CPPFLAGS="$HARDENED_CPPFLAGS -U_FORTIFY_SOURCE"
    755 | +  if test x$enable_debug != xyes; then
   

   ---

   ---

   

   laanwj commented at 5:38 AM on October 4, 2019:

   Maybe add a comment here (to explain the problem with debug here)

   ---

   

   achow101 commented at 6:22 PM on October 7, 2019:

   Done

8. Disable _FORTIFY_SOURCE when enable-debug

   Since enable-debug disables optimization entirely, _FORTIFY_SOURCE
   does nothing as it requires some kind of optimization enabled. It
   instead produces a bunch of useless warnings. So explicitly disable
   it when enable-debug so that those warnings are not produced.

   44f7a8d7a7
9. achow101 force-pushed on Oct 7, 2019
10. 
    laanwj commented at 8:27 AM on October 8, 2019: member

    Thanks. ACK 44f7a8d7a774f82417106c452d793e6f091bc23e

11. laanwj requested review from dongcarl on Oct 8, 2019
12. laanwj requested review from theuni on Oct 8, 2019
13. laanwj referenced this in commit ee47461ea5 on Oct 15, 2019
14. laanwj merged this on Oct 15, 2019
15. laanwj closed this on Oct 15, 2019

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16. sidhujag referenced this in commit 82b285b411 on Oct 16, 2019
17. 
    luke-jr commented at 2:03 PM on November 4, 2019: member

    Posthumourous Concept NACK: --enable-debug can be used with explicitly-specified -On options, and that _FORTIFY_SOURCE currently does nothing for -O0 is a compiler detail, not inherent.

18. MarkLTZ referenced this in commit 3b69b903d9 on Apr 6, 2020
19. deadalnix referenced this in commit fc846cd036 on May 25, 2020
20. PastaPastaPasta referenced this in commit ef2c36a0d8 on Jun 27, 2021
21. PastaPastaPasta referenced this in commit 377a7b72fd on Jun 28, 2021
22. PastaPastaPasta referenced this in commit 0fb153c3a0 on Jun 29, 2021
23. PastaPastaPasta referenced this in commit 90b5c9cf54 on Jul 1, 2021
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28. MarcoFalke locked this on Dec 16, 2021

Contributors

achow101laanwjluke-jr

Review Requested
theunidongcarl