Fails to build from source on prerelease Ubuntu, GCC

[jwbee]

Problem:

The quickstart instructions do not succeed using the tools and libraries of Ubuntu 24.04, which will be released in a month. It fails whether I use GCC 12 or 13. It succeeds with clang 17.

% cmake --build build
[  0%] Building C object CMakeFiles/s2n.dir/crypto/s2n_aead_cipher_aes_gcm.c.o
<command-line>: error: "_FORTIFY_SOURCE" redefined [-Werror]
<built-in>: note: this is the location of the previous definition
cc1: all warnings being treated as errors
gmake[2]: *** [CMakeFiles/s2n.dir/build.make:76: CMakeFiles/s2n.dir/crypto/s2n_aead_cipher_aes_gcm.c.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:1365: CMakeFiles/s2n.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2

[jwbee]

It appears that a solution might be:

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5713558d3..55d33a548 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -176,6 +176,7 @@ target_compile_options(${PROJECT_NAME} PUBLIC -fPIC)

 add_definitions(-D_POSIX_C_SOURCE=200809L)
 if(CMAKE_BUILD_TYPE MATCHES Release)
+    add_definitions(-U_FORTIFY_SOURCE)
     add_definitions(-D_FORTIFY_SOURCE=2)
 endif()

[camshaft]

Hey thanks for reaching out. I don't think we want to completely unset the variable but instead should only set it if it hasn't already been defined. I can get a PR out to try and address that.

[camshaft]

I've opened #4465, which should address the issue. Just need to work through the OpenBSD failure before merging it. If you want to try out my branch to confirm it fixes what you're seeing, that would also be helpful 😃

[jwbee]

It is fixed for me on your tree.

[goatgoose]

Hi @jwbee, I've executed the ubuntu quickstart instructions on a Ubuntu 24.04 instance and have been unsuccessful in reproducing this issue so far. I've tried using GCC 12 and 13, and both succeeded. I wonder if the behavior could have changed since the prerelease. Are you still running into this issue with the final 24.04 release?

[jwbee]

You're right, it builds and tests on the release ubuntu, from main branch.