feat: apply hardened_malloc using LD_PRELOAD for user processes#1150
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RoyalOughtness merged 4 commits intosecureblue:livefrom Jun 26, 2025
Merged
feat: apply hardened_malloc using LD_PRELOAD for user processes#1150RoyalOughtness merged 4 commits intosecureblue:livefrom
RoyalOughtness merged 4 commits intosecureblue:livefrom
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This reworks how hardened_malloc is applied: * For root-owned processes (including PID 1), `/etc/ld.so.preload` continues to be used to preload hardened_malloc; however, `/etc/ld.so.preload` is changed to only be readable by root. * `LD_PRELOAD=libhardened_malloc.so` is set in `/etc/environment`, which applies hardened_malloc to user processes. The impact is that hardened_malloc is still loaded by default for all processes, but non-root-owned processes can override it by unsetting `LD_PRELOAD`, rather than having to use user namespaces to prevent `ld.so.preload` from being read. This means that `ujust with-standard-malloc` no longer requires unconfined user namespace creation, and it has been made into a simple wrapper that unsets `LD_PRELOAD` for the passed command. The audit script has been modified to align with the new method of preloading hardened_malloc.
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…reblue#1150) * feat: apply hardened_malloc using LD_PRELOAD for user processes This reworks how hardened_malloc is applied: * For root-owned processes (including PID 1), `/etc/ld.so.preload` continues to be used to preload hardened_malloc; however, `/etc/ld.so.preload` is changed to only be readable by root. * `LD_PRELOAD=libhardened_malloc.so` is set in `/etc/environment`, which applies hardened_malloc to user processes. The impact is that hardened_malloc is still loaded by default for all processes, but non-root-owned processes can override it by unsetting `LD_PRELOAD`, rather than having to use user namespaces to prevent `ld.so.preload` from being read. This means that `ujust with-standard-malloc` no longer requires unconfined user namespace creation, and it has been made into a simple wrapper that unsets `LD_PRELOAD` for the passed command. The audit script has been modified to align with the new method of preloading hardened_malloc.
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This reworks how hardened_malloc is applied:
/etc/ld.so.preloadcontinues to be used to preload hardened_malloc; however,/etc/ld.so.preloadis changed to only be readable by root.LD_PRELOAD=libhardened_malloc.sois set in/usr/lib/environment.d/40-hardened_malloc.conf, which applies hardened_malloc to user processes.The impact is that hardened_malloc is still loaded by default for all processes, but non-root-owned processes can override it by unsetting
LD_PRELOAD, rather than having to use user namespaces to preventld.so.preloadfrom being read.This means that
ujust with-standard-mallocno longer requires unconfined user namespace creation, and it has been made into a simple wrapper that unsetsLD_PRELOADfor the passed command.The audit script has been modified to align with the new method of preloading hardened_malloc.