From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755338Ab0IQPJn (ORCPT ); Fri, 17 Sep 2010 11:09:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61889 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755317Ab0IQPJk (ORCPT ); Fri, 17 Sep 2010 11:09:40 -0400 Date: Fri, 17 Sep 2010 11:09:08 -0400 From: Jason Baron To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, mathieu.desnoyers@polymtl.ca, hpa@zytor.com, tglx@linutronix.de, rostedt@goodmis.org, andi@firstfloor.org, roland@redhat.com, rth@redhat.com, mhiramat@redhat.com, fweisbec@gmail.com, avi@redhat.com, davem@davemloft.net, vgoyal@redhat.com, sam@ravnborg.org, tony@bakeyournoodle.com Message-Id: <06236663a3a7b1c1f13576bb9eccb6d9c17b7bfe.1284733808.git.jbaron@redhat.com> In-Reply-To: References: Subject: [PATCH 05/10] jump label v11: jump_label_text_reserved() to reserve our jump points Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a jump_label_text_reserved(void *start, void *end), so that other pieces of code that want to modify kernel text, can first verify that jump label has not reserved the instruction. Signed-off-by: Jason Baron Acked-by: Masami Hiramatsu --- arch/x86/kernel/kprobes.c | 3 +- include/linux/jump_label.h | 8 ++++- kernel/jump_label.c | 83 ++++++++++++++++++++++++++++++++++++++++++++ kernel/kprobes.c | 3 +- 4 files changed, 94 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 770ebfb..788fade 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -1221,7 +1221,8 @@ static int __kprobes copy_optimized_instructions(u8 *dest, u8 *src) } /* Check whether the address range is reserved */ if (ftrace_text_reserved(src, src + len - 1) || - alternatives_text_reserved(src, src + len - 1)) + alternatives_text_reserved(src, src + len - 1) || + jump_label_text_reserved(src, src + len - 1)) return -EBUSY; return len; diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index de58656..b72cd9f 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -20,9 +20,10 @@ extern struct jump_entry __stop___jump_table[]; extern void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type); +extern void arch_jump_label_text_poke_early(jump_label_t addr); extern void jump_label_update(unsigned long key, enum jump_label_type type); extern void jump_label_apply_nops(struct module *mod); -extern void arch_jump_label_text_poke_early(jump_label_t addr); +extern int jump_label_text_reserved(void *start, void *end); #define enable_jump_label(key) \ jump_label_update((unsigned long)key, JUMP_LABEL_ENABLE); @@ -53,6 +54,11 @@ static inline int jump_label_apply_nops(struct module *mod) return 0; } +static inline int jump_label_text_reserved(void *start, void *end) +{ + return 0; +} + #endif #endif diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 07656ec..f82878b 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -174,6 +174,89 @@ void jump_label_update(unsigned long key, enum jump_label_type type) mutex_unlock(&jump_label_mutex); } +static int addr_conflict(struct jump_entry *entry, void *start, void *end) +{ + if (entry->code <= (unsigned long)end && + entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start) + return 1; + + return 0; +} + +#ifdef CONFIG_MODULES + +static int module_conflict(void *start, void *end) +{ + struct hlist_head *head; + struct hlist_node *node, *node_next, *module_node, *module_node_next; + struct jump_label_entry *e; + struct jump_label_module_entry *e_module; + struct jump_entry *iter; + int i, count; + int conflict = 0; + + for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) { + head = &jump_label_table[i]; + hlist_for_each_entry_safe(e, node, node_next, head, hlist) { + hlist_for_each_entry_safe(e_module, module_node, + module_node_next, + &(e->modules), hlist) { + count = e_module->nr_entries; + iter = e_module->table; + while (count--) { + if (addr_conflict(iter, start, end)) { + conflict = 1; + goto out; + } + iter++; + } + } + } + } +out: + return conflict; +} + +#endif + +/*** + * jump_label_text_reserved - check if addr range is reserved + * @start: start text addr + * @end: end text addr + * + * checks if the text addr located between @start and @end + * overlaps with any of the jump label patch addresses. Code + * that wants to modify kernel text should first verify that + * it does not overlap with any of the jump label addresses. + * + * returns 1 if there is an overlap, 0 otherwise + */ +int jump_label_text_reserved(void *start, void *end) +{ + struct jump_entry *iter; + struct jump_entry *iter_start = __start___jump_table; + struct jump_entry *iter_stop = __start___jump_table; + int conflict = 0; + + mutex_lock(&jump_label_mutex); + iter = iter_start; + while (iter < iter_stop) { + if (addr_conflict(iter, start, end)) { + conflict = 1; + goto out; + } + iter++; + } + + /* now check modules */ +#ifdef CONFIG_MODULES + conflict = module_conflict(start, end); +#endif +out: + mutex_unlock(&jump_label_mutex); + return conflict; +} + static __init int init_jump_label(void) { int ret; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 798adfa..a53bff3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1142,7 +1142,8 @@ int __kprobes register_kprobe(struct kprobe *p) preempt_disable(); if (!kernel_text_address((unsigned long) p->addr) || in_kprobes_functions((unsigned long) p->addr) || - ftrace_text_reserved(p->addr, p->addr)) { + ftrace_text_reserved(p->addr, p->addr) || + jump_label_text_reserved(p->addr, p->addr)) { preempt_enable(); return -EINVAL; } -- 1.7.1