Messages in this thread | | | Date | Mon, 16 Jun 2014 14:48:54 -0700 | From | "H. Peter Anvin" <> | Subject | Re: 3.15: kernel BUG at kernel/auditsc.c:1525! |
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On 06/16/2014 02:35 PM, Andy Lutomirski wrote: > > To hpa, etc: It appears that entry_32.S is missing any call to the > audit exit hook on the badsys path. If I'm diagnosing this bug report > correctly, this causes OOPSes. > > The the world at large: it's increasingly apparent that no one (except > maybe the blackhats) has ever scrutinized the syscall auditing code. > This is two old severe bugs in the code that have probably been there > for a long time. >
Yes, the audit code is a total mess.
> The bad syscall nr paths are their own incomprehensible route > through the entry control flow. Rearrange them to work just like > syscalls that return -ENOSYS.
I have to admit... it sort of lends itself to a solution like this:
/* For the 64-bit case, analogous code for 32 bits */ movl $__NR_syscall_max+1,%ecx # *Not* __NR_syscall_max cmpq %rcx,%rax cmovae %rcx,%rax movq %r10,%rcx call *sys_call_table(,%rax,8)
... and having an extra (invalid) system call slot in the syscall table beyond the end instead of branching off separately.
(Note: we could use either cmova or cmovae, and either the 32- or 64-bit form... the reason why is left as an exercise to the reader.)
-hpa
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