Enable stack smash protections by default

Disabled on platforms which use compilers that do not support the
`-fstack-protector` compiler flag.

Author: nmeum

Makefile.dep

@@ -19,6 +19,10 @@ OLD_USEPKG := $(sort $(USEPKG))
 include $(RIOTBASE)/sys/Makefile.dep
 include $(RIOTBASE)/drivers/Makefile.dep
 
+ifeq (,$(RIOTNOSSP))
+  USEMODULE += ssp
+endif
+
 ifneq (,$(filter ndn-riot,$(USEPKG)))
   USEMODULE += gnrc
   USEMODULE += xtimer

cpu/atmega_common/Makefile.include

@@ -9,4 +9,7 @@ USEMODULE += avr_libc_extra
 PSEUDOMODULES += atmega_pcint
 PSEUDOMODULES += atmega_pcint%
 
+# avr-gcc does not support -fstack-protector
+RIOTNOSSP = 1
+
 include $(RIOTMAKE)/arch/atmega.inc.mk

cpu/mips_pic32_common/Makefile.include

@@ -4,3 +4,6 @@ INCLUDES += -I$(RIOTCPU)/mips_pic32_common/include
 
 USEMODULE += mips_pic32_common
 USEMODULE += mips_pic32_common_periph
+
+# compiler does not support -fstack-protector
+RIOTNOSSP = 1

cpu/msp430_common/Makefile.include

@@ -9,5 +9,8 @@ export USEMODULE += msp430_common msp430_common_periph msp430_malloc
 
 DEFAULT_MODULE += oneway_malloc
 
+# compiler does not support -fstack-protector
+RIOTNOSSP = 1
+
 # include the msp430 common Makefile
 include $(RIOTMAKE)/arch/msp430.inc.mk

makefiles/vars.inc.mk

@@ -28,6 +28,7 @@ export APPDEPS               # Files / Makefile targets that need to be created
 export RIOTBASE              # The root folder of RIOT. The folder where this very file lives in.
 export RIOTCPU               # For third party CPUs this folder is the base of the CPUs.
 export RIOTBOARD             # This folder is the base of the riot boards.
+export RIOTNOSSP             # Disable stack smash protections. NOT RECOMMENDED.
 export BOARDSDIR             # For third party BOARDs this folder is the base of the BOARDs.
 export RIOTPKG               # For overriding RIOT's pkg directory
 export RIOTTOOLS             # Location of host machine tools