Messages in this thread | | | Subject | Re: [PATCH] uts: Don't randomize "struct uts_namespace". | From | Tetsuo Handa <> | Date | Sat, 7 Jul 2018 08:10:08 +0900 |
| |
Hello Ken'ichi,
I noticed that makedumpfile ( https://sourceforge.net/p/makedumpfile/code/ ) can no longer detect kernel version correctly because "struct uts_namespace" (which is exposed to userspace via vmcoreinfo) is subjected to randomization by GCC_PLUGIN_RANDSTRUCT kernel config option since 4.13.
The code was introduced by below commit.
commit bfc8fe181c822ad0d8495ceda3c7109a407192f0 Author: ken1_ohmichi <ken1_ohmichi> Date: Fri Dec 22 07:41:14 2006 +0000
linux-2.6.19 support. On linux-2.6.18 or former, the release information could be gotten from the symbol "system_utsname". But on linux-2.6.19, it can be done from the symbol "init_uts_ns". A new makedumpfile can get the release information from the existing symbol.
Can you detect kernel version without using "struct uts_namespace" ?
On 2018/07/07 1:11, Linus Torvalds wrote: > On Fri, Jul 6, 2018 at 3:07 AM Tetsuo Handa > <penguin-kernel@i-love.sakura.ne.jp> wrote: >> >> I noticed that makedumpfile utility is failing to check kernel version, for >> it depends on offset of "struct uts_namespace"->name being sizeof(int). > > For something like this, we fix makedumpfile instead. This is not a > "user program" using system calls etc, this is something that delves > into the kernel dump and tries to make sense of it. > > Where is the makedumpfile source code? What is it trying to do, and why? > > One option is to just say "hey, you can't make much sense of a > randomized kernel dump anyway, so don't even try". > > Linus >
| |