Messages in this thread | | | Date | Fri, 7 Dec 2018 18:00:26 +0100 | From | Andrea Righi <> | Subject | Re: [PATCH] kprobes: x86_64: blacklist non-attachable interrupt functions |
| |
On Sat, Dec 08, 2018 at 01:01:20AM +0900, Masami Hiramatsu wrote: > Hi Andrea and Ingo, > > Here is the patch what I meant. I just ran it on qemu-x86, and seemed working. > After introducing this patch, I will start adding arch_populate_kprobe_blacklist() > to some arches. > > Thank you, > > [RFC] kprobes: x86/kprobes: Blacklist symbols in arch-defined prohibited area > > From: Masami Hiramatsu <mhiramat@kernel.org> > > Blacklist symbols in arch-defined probe-prohibited areas. > With this change, user can see all symbols which are prohibited > to probe in debugfs. > > All archtectures which have custom prohibit areas should define > its own arch_populate_kprobe_blacklist() function, but unless that, > all symbols marked __kprobes are blacklisted. > > Reported-by: Andrea Righi <righi.andrea@gmail.com> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > ---
[snip]
> +int kprobe_add_ksym_blacklist(unsigned long entry) > +{ > + struct kprobe_blacklist_entry *ent; > + unsigned long offset = 0, size = 0; > + > + if (!kernel_text_address(entry) || > + !kallsyms_lookup_size_offset(entry, &size, &offset)) > + return -EINVAL; > + > + ent = kmalloc(sizeof(*ent), GFP_KERNEL); > + if (!ent) > + return -ENOMEM; > + ent->start_addr = entry - offset; > + ent->end_addr = entry - offset + size;
Do we need to take offset into account? The code before wasn't using it.
> + INIT_LIST_HEAD(&ent->list); > + list_add_tail(&ent->list, &kprobe_blacklist); > + > + return (int)size; > +} > + > +/* Add functions in arch defined probe-prohibited area */ > +int __weak arch_populate_kprobe_blacklist(void) > +{ > + unsigned long entry; > + int ret = 0; > + > + for (entry = (unsigned long)__kprobes_text_start; > + entry < (unsigned long)__kprobes_text_end; > + entry += ret) { > + ret = kprobe_add_ksym_blacklist(entry); > + if (ret < 0) > + return ret; > + if (ret == 0) /* In case of alias symbol */ > + ret = 1; > + } > + return 0; > +} > + > /* > * Lookup and populate the kprobe_blacklist. > * > @@ -2104,26 +2142,20 @@ NOKPROBE_SYMBOL(dump_kprobe); > static int __init populate_kprobe_blacklist(unsigned long *start, > unsigned long *end) > { > + unsigned long entry; > unsigned long *iter; > - struct kprobe_blacklist_entry *ent; > - unsigned long entry, offset = 0, size = 0; > + int ret; > > for (iter = start; iter < end; iter++) { > entry = arch_deref_entry_point((void *)*iter); > - > - if (!kernel_text_address(entry) || > - !kallsyms_lookup_size_offset(entry, &size, &offset)) > + ret = kprobe_add_ksym_blacklist(entry); > + if (ret == -EINVAL) > continue; > - > - ent = kmalloc(sizeof(*ent), GFP_KERNEL); > - if (!ent) > - return -ENOMEM; > - ent->start_addr = entry; > - ent->end_addr = entry + size; > - INIT_LIST_HEAD(&ent->list); > - list_add_tail(&ent->list, &kprobe_blacklist); > + if (ret < 0) > + return ret; > } > - return 0; > + > + return arch_populate_kprobe_blacklist(); > } > > /* Module notifier call back, checking kprobes on the module */
| |