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[79.27.126.34]) by smtp.gmail.com with ESMTPSA id h12sm9755756wma.48.2018.12.07.09.00.26 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 07 Dec 2018 09:00:27 -0800 (PST) Date: Fri, 7 Dec 2018 18:00:26 +0100 From: Andrea Righi To: Masami Hiramatsu Cc: "Naveen N. Rao" , Anil S Keshavamurthy , "David S. Miller" , Yonghong Song , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kprobes: x86_64: blacklist non-attachable interrupt functions Message-ID: <20181207170026.GA1379@Dell> References: <20181206095648.GA8249@Dell> <20181207234731.f52a8c1eff6c0e72c073ad40@kernel.org> <20181208010120.c3eda9042912068aecc68317@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181208010120.c3eda9042912068aecc68317@kernel.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > > 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 > Signed-off-by: Masami Hiramatsu > --- [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 */