linux-kernel - Re: [PATCH v2 3/4] gendwarfksyms: Add a kABI rule to override type strings

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <7803cd39-8b40-4956-86de-f2750d8e3b13@suse.com>
Date: Tue, 6 May 2025 11:25:16 +0200
From: Petr Pavlu <petr.pavlu@...e.com>
To: Sami Tolvanen <samitolvanen@...gle.com>
Cc: Masahiro Yamada <masahiroy@...nel.org>,
 Luis Chamberlain <mcgrof@...nel.org>, Daniel Gomez <da.gomez@...sung.com>,
 linux-modules@...r.kernel.org, linux-kbuild@...r.kernel.org,
 linux-kernel@...r.kernel.org, Giuliano Procida <gprocida@...gle.com>
Subject: Re: [PATCH v2 3/4] gendwarfksyms: Add a kABI rule to override type
 strings

On 5/5/25 23:24, Sami Tolvanen wrote:
> In rare situations where distributions must make significant
> changes to otherwise opaque data structures that have
> inadvertently been included in the published ABI, keeping
> symbol versions stable using the existing kABI macros can
> become tedious.
> 
> For example, Android decided to switch to a newer io_uring
> implementation in the 5.10 GKI kernel "to resolve a huge number
> of potential, and known, problems with the codebase," requiring
> "horrible hacks" with genksyms:
> 
>   "A number of the io_uring structures get used in other core
>   kernel structures, only as "opaque" pointers, so there is
>   not any real ABI breakage.  But, due to the visibility of
>   the structures going away, the CRC values of many scheduler
>   variables and functions were changed."
>     -- https://r.android.com/2425293
> 
> While these specific changes probably could have been hidden
> from gendwarfksyms using the existing kABI macros, this may not
> always be the case.
> 
> Add a last resort kABI rule that allows distribution
> maintainers to fully override a type string for a symbol or a
> type. Also add a more informative error message in case we find
> a non-existent type references when calculating versions.
> 
> Suggested-by: Giuliano Procida <gprocida@...gle.com>
> Signed-off-by: Sami Tolvanen <samitolvanen@...gle.com>

Reviewed-by: Petr Pavlu <petr.pavlu@...e.com>

-- 
Thanks,
Petr