Generate modules.builtin.alias from match ids This patch series (v7) pivots to adding `modules.builtin.alias` from the previous approach of adding a sysfs attribute. The goal is for tools like USBGuard to leverage not only modules.aliases but also `modules.builtin.aliases` to associate devices with the modules that may be bound before deciding to authorize a device or not. This is particularly useful in cases when new devices of a particular type shouldn't be allowed part of the time like for lock screens. Note that `modules.builtin.alias` is generated directly by modpost. This differs from how `modules.alias` is generated because modpost converts the match-id based module aliases into c-files that add additional aliases to the module info. No such c-file is present for vmlinuz though it would be possible to add one. A downside of this would be vmlinuz would grow by 100-200kb for a typical ChromeOS kernel config. -- # Generate modules.builtin.alias from match ids Previous versions of this patch series addressed the same problem by adding a sysfs attribute instead of `modules.builtin.alias`. Consequently, they have a different name and include completely different commits than this version. Note, cover letters were first added in v5. RFC (broken patch): https://lore.kernel.org/lkml/CAJzde042-M4UbpNYKw0eDVg4JqYmwmPYSsmgK+kCMTqsi+-2Yw@xxxxxxxxxxxxxx/ v1 (missing v1 label): https://lore.kernel.org/lkml/20221111152852.2837363-1-allenwebb@xxxxxxxxxx/ v2 (missing v2 label): https://lore.kernel.org/lkml/20221128201332.3482092-1-allenwebb@xxxxxxxxxx/ v3: https://lore.kernel.org/lkml/20221129224313.455862-1-allenwebb@xxxxxxxxxx/ v4: https://lore.kernel.org/lkml/20221130221447.1202206-1-allenwebb@xxxxxxxxxx/ v5: https://lore.kernel.org/lkml/20221201211630.101541-1-allenwebb@xxxxxxxxxx/ v6: https://lore.kernel.org/lkml/20221202224540.1446952-1-allenwebb@xxxxxxxxxx/ v7: This version ## Patch series status This series is still going through revisions in response to comments. This version generates match-id based aliases for all subsystems unlike previous patch series versions which only implemented aliases for USB. I believe there is potential to improve the Makefile part of the patch series as well as an open question of whether modpost should generate `modules.built.alias` directly or create a vmlinuz.mod.c containing the missing module info for the match-id based aliases for built-in modules. ## Acknowledgements Thanks to Greg Kroah-Hartman and the Linux maintainers for being patient with me as I have worked through learning the kernel workflow to get this series into a more presentable state. Thanks to Luis Chamberlain for raising the alternative of using kmod to address the primary motivation of the patch series. Also, thanks to Intel's kernel test robot <lkp@xxxxxxxxx> for catching issues that showed up on different kernel configurations. Allen Webb (5): module.h: MODULE_DEVICE_TABLE for built-in modules modpost: Track module name for built-in modules modpost: Add -b option for emitting built-in aliases file2alias.c: Implement builtin.alias generation build: Add modules.builtin.alias .gitignore | 1 + Makefile | 1 + include/linux/module.h | 10 ++++- scripts/Makefile.modpost | 17 +++++++- scripts/mod/file2alias.c | 92 +++++++++++++++++++++++++++++++--------- scripts/mod/modpost.c | 23 +++++++++- scripts/mod/modpost.h | 2 + 7 files changed, 121 insertions(+), 25 deletions(-) -- 2.37.3
