To enable "PIE" and "BINDNOW" use DEB_BUILD_MAINT_OPTIONS in combination with buildflags.mk as explained above. Due to #651966 it used to not be possible to use DEB_BUILD_MAINT_OPTIONS directly. For example, to enable the "pie" feature and disable the "fortify" feature you can do this in debian/rules:Įxport DEB_BUILD_MAINT_OPTIONS=hardening=+pie,-fortifyĬDBS packages automatically export all dpkg-buildflags (Bug #651964 was fixed). The "all" option enables "PIE" and "BINDNOW" and future hardening flags:Įnable or disable certain hardening features separatelyĮach hardening feature can be enabled and disabled in the DEB_BUILD_MAINT_OPTIONS environment variable's hardening value with the "+" and "-" modifier. When building programs that handle untrusted data (parsers, network listeners, etc.), or run with elevated privileges (PAM, X, etc.), please enable "PIE" and "BINDNOW" in the build. This also works with DEB_BUILD_MAINT_OPTIONS, just declare it before the include (needs dpkg-dev >= 1.16.1.1):Įxport DEB_BUILD_MAINT_OPTIONS = hardening=+all use CFLAGS += -Wextra instead of CFLAGS = -Wextra:
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Make sure to append to the *FLAGS instead of overwriting them, e.g.
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Or you can use the new buildflags.mk file (dpkg-dev >= 1.16.1~) to set all *FLAGS:īuildflags.mk overwrites the *FLAGS, so additions to the flags must happen after the include. $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o hello.o hello.c LDFLAGS:=$(shell dpkg-buildflags -get LDFLAGS) To use "dpkg-buildflags", either switch to dh(1) to do builds (requires debhelper compat level >= 9), or use it directly in your builds to set the default compiler and linker flags:ĬPPFLAGS:=$(shell dpkg-buildflags -get CPPFLAGS)ĬFLAGS:=$(shell dpkg-buildflags -get CFLAGS)ĬXXFLAGS:=$(shell dpkg-buildflags -get CXXFLAGS) See ReleaseGoals/SecurityHardeningBuildFlags for additional information.įor a step-by-step guide, see the HardeningWalkthrough. Using "dpkg-buildflags" is the recommended way to incorporate the build flags in Debian. Several compile-time options (detailed below) can be used to help harden a resulting binary against memory corruption attacks, or provide additional warning messages during compiles. non-exec memory segmentation (ExecShield).Notes on Memory Corruption Mitigation Methods.DEB_BUILD_HARDENING_BINDNOW (ld -z now).DEB_BUILD_HARDENING_RELRO (ld -z relro).DEB_BUILD_HARDENING_PIE (gcc/g++ -fPIE -pie).DEB_BUILD_HARDENING_STACKPROTECTOR (gcc/g++ -fstack-protector-strong).DEB_BUILD_HARDENING_FORTIFY (gcc/g++ -D_FORTIFY_SOURCE=2).DEB_BUILD_HARDENING_FORMAT (gcc/g++ -Wformat -Wformat-security -Werror=format-security).
![c++ stack smashing detected low memory c++ stack smashing detected low memory](https://payatu.com/static/blogheaderimg/asmita-jha/hardwareattack/imageBlog.png)