Messages in this thread Patch in this message | | | Date | Sat, 8 Dec 2018 01:01:20 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH] kprobes: x86_64: blacklist non-attachable interrupt functions |
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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> --- arch/x86/kernel/kprobes/core.c | 27 ++++++++++++++++++ include/linux/kprobes.h | 2 + kernel/kprobes.c | 60 +++++++++++++++++++++++++++++++--------- 3 files changed, 75 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index c33b06f..52771e3 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -1034,6 +1034,33 @@ bool arch_within_kprobe_blacklist(unsigned long addr) addr < (unsigned long)__entry_text_end); } +int __init 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; + } + + for (entry = (unsigned long)__entry_text_start; + entry < (unsigned long)__entry_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; +} + int __init arch_init_kprobes(void) { return 0; diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index e909413..a68cbbe 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -242,10 +242,12 @@ extern int arch_init_kprobes(void); extern void show_registers(struct pt_regs *regs); extern void kprobes_inc_nmissed_count(struct kprobe *p); extern bool arch_within_kprobe_blacklist(unsigned long addr); +extern int arch_populate_kprobe_blacklist(void); extern bool arch_kprobe_on_func_entry(unsigned long offset); extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset); extern bool within_kprobe_blacklist(unsigned long addr); +extern int kprobe_add_ksym_blacklist(unsigned long entry); struct kprobe_insn_cache { struct mutex mutex; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 90e98e2..8b2eb62 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2093,6 +2093,44 @@ void dump_kprobe(struct kprobe *kp) } NOKPROBE_SYMBOL(dump_kprobe); +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; + 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 */
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