Package: glibc-source Severity: wishlist Tags: patch glibc 2.33 onwards has support for 'Memory Tagging Extension' on arm64. Could you please enable this feature (by setting --enable-memory-tagging in the config).
The effect is to add colouring bits into heap pointers so that typical illegal accesses (either temporally or spatially) can be detected and faulted. Glibc just has the userspace heap tagging - there is also corresponding kernel support. The functionality operates on arm ISA 8.5 or later, which has extra instructions to manipulate the tag bits in pointers. The details are explained in https://developer.arm.com/-/media/Arm%20Developer%20Community/PDF/Arm_Memory_Tagging_Extension_Whitepaper.pdf The implementation has been designed so that it is safe to enable in distros (which makes a change!). ifunc and HWCAP are used to link MTE-ready versions of relevant functions on hardware supporting ARMv8.5 instruction set or later. On eailer hardware things will work just as they do now. Here is the (trivial) patch: diff -u debian/sysdeps/arm64.mk~ debian/sysdeps/arm64.mk --- debian/sysdeps/arm64.mk~ 2021-08-24 14:31:06.000000000 +0000 +++ debian/sysdeps/arm64.mk 2021-09-28 19:43:58.782118977 +0000 @@ -1,2 +1,2 @@ # configuration options for all flavours -extra_config_options = --enable-multi-arch --enable-static-pie +extra_config_options = --enable-multi-arch --enable-static-pie --enable-memory-tagging -- Wookey
