Hardened Malloc and memory tagging relevance for memory safe apps?

Eumenia

Do's hardened memory allocator and memory tagging makes any difference for apps that are entirely written in memory save languages (which are most languages, especially those used to write Android apps, like Kotlin)

de0u

Eumenia So far, everything contains bugs... that includes language runtimes (such as the JVM used to run Java and Kotlin), and also lots of library code that is used by programs written in safe languages (such as image processing).

The notion that memory-safe languages are a magic wand is probably 30 to 40 years old, but if we get there it won't be for at least 10 more.

Eumenia

de0u So far, everything contains bugs... that includes language runtimes (such as the JVM used to run Java and Kotlin), and also lots of library code that is used by programs written in safe languages (such as image processing).

The notion that memory-safe languages are a magic wand is probably 30 to 40 years old, but if we get there it won't be for at least 10 more.

Yes, but this other bugs are not in the scope of memory allocation and tagging as far as I know.
It mainly focuses on buffer overflows and use-after-free vulnerabilities which only really happen in C, C++ and C#, not in for example Kotlin

de0u

Eumenia When a Kotlin program is still in its original form as Kotlin source code, it contains no memory unsafety issues. But running a Kotlin program depends on some execution engine, probably written in a mixture of C and C++, and that Kotlin program very likely calls library code that is written in C and C++. Hardening all of that code is absolutely still useful.

Eumenia

de0u When a Kotlin program is still in its original form as Kotlin source code, it contains no memory unsafety issues. But running a Kotlin program depends on some execution engine, probably written in a mixture of C and C++, and that Kotlin program very likely calls library code that is written in C and C++. Hardening all of that code is absolutely still useful.

So it's still important for the sake of library exploit protection
Thanks for the answer.