On Tuesday 23 January 2007 12:44, Andrew N. Below wrote: > System - RELENG_6. > > Easiest way I found is to patch libc. > But in this case we still can get an original library and use > LD_PRELOAD. > > Is there any way to obtain uid of calling process (thread?) > within the kernel? > > We have following extern in src/lib/libc/gen/sysctl.c: > [..] > extern int __sysctl(int *name, u_int namelen, void *oldp, size_t > *oldlenp, void *newp, size_t newlen); > [..] > > And there is __sysctl (src/sys/kern/kern_sysctl.c): > > [..] > /* > * MPSAFE > */ > int > __sysctl(struct thread *td, struct sysctl_args *uap) > [..] > > 1. Whether this function is called from libc sysctl() ? > > 2. What can we get from td here? My knowledge about FreeBSD kernel > and kernel threads is not yet enough for understanding this.
td->td_proc->p_ucred has the user credentials. You probably want to do your checks in userland_sysctl() according to the comment just above. > I also thought about passing control variable from libc > to kernel, but it seems to be bad idea. > > Any other ways? -- /"\ Best regards, | [EMAIL PROTECTED] \ / Max Laier | ICQ #67774661 X http://pf4freebsd.love2party.net/ | [EMAIL PROTECTED] / \ ASCII Ribbon Campaign | Against HTML Mail and News
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