From patchwork Wed Feb 15 11:54:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Jihong X-Patchwork-Id: 13141564 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A614C64ED8 for ; Wed, 15 Feb 2023 11:56:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231269AbjBOL4s (ORCPT ); Wed, 15 Feb 2023 06:56:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232544AbjBOL4q (ORCPT ); Wed, 15 Feb 2023 06:56:46 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D88628842; Wed, 15 Feb 2023 03:56:44 -0800 (PST) Received: from kwepemm600003.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4PGxPD6f26zrRvN; Wed, 15 Feb 2023 19:56:16 +0800 (CST) Received: from ubuntu1804.huawei.com (10.67.174.61) by kwepemm600003.china.huawei.com (7.193.23.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Wed, 15 Feb 2023 19:56:40 +0800 From: Yang Jihong To: , , , , , , , , , , , , , CC: Subject: [PATCH 1/3] kprobes: Fixed probe nodes not correctly removed when forcibly unoptimized Date: Wed, 15 Feb 2023 19:54:28 +0800 Message-ID: <20230215115430.236046-2-yangjihong1@huawei.com> X-Mailer: git-send-email 2.30.GIT In-Reply-To: <20230215115430.236046-1-yangjihong1@huawei.com> References: <20230215115430.236046-1-yangjihong1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.174.61] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600003.china.huawei.com (7.193.23.202) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org When unoptimize_kprobe forcibly unoptimize the kprobe, simply queue it in the freeing_list, and do_free_cleaned_kprobes directly reclaims the kprobe if unoptimizing_list is empty (see do_unoptimize_kprobes), which may cause WARN or UAF problems. The specific scenarios are as follows: Thread1 arm_kprobe(p) mutex_lock(&kprobe_mutex) __arm_kprobe(kp) p = get_optimized_kprobe(p->addr) if (unlikely(_p)) unoptimize_kprobe(_p, true) // now _p is queued in freeing_list mutex_unlock(&kprobe_mutex) Thread2 kprobe_optimizer mutex_lock(&kprobe_mutex) do_unoptimize_kprobes if (list_empty(&unoptimizing_list)) return; // here directly returned and does not process freeing_list. ... do_free_cleaned_kprobes foreach op in freeing_list: WARN_ON_ONCE(!kprobe_unused(&op->kp)) // WANR will be triggered here. free_aggr_kprobe((&op->kp) // Delete op->kp directly, if access hash // list later, UAF problem will be triggered. mutex_unlock(&kprobe_mutex) The freeing_list needs to be processed in do_unoptimize_kprobes regardless of whether unoptimizing_list is empty. Signed-off-by: Yang Jihong --- kernel/kprobes.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 1c18ecf9f98b..0730e595f4c1 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -556,10 +556,9 @@ static void do_unoptimize_kprobes(void) lockdep_assert_cpus_held(); /* Unoptimization must be done anytime */ - if (list_empty(&unoptimizing_list)) - return; + if (!list_empty(&unoptimizing_list)) + arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); - arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); /* Loop on 'freeing_list' for disarming */ list_for_each_entry_safe(op, tmp, &freeing_list, list) { /* Switching from detour code to origin */ From patchwork Wed Feb 15 11:54:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Jihong X-Patchwork-Id: 13141563 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51A2EC636CC for ; Wed, 15 Feb 2023 11:56:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233826AbjBOL4r (ORCPT ); Wed, 15 Feb 2023 06:56:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232100AbjBOL4q (ORCPT ); Wed, 15 Feb 2023 06:56:46 -0500 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50EFB360BE; Wed, 15 Feb 2023 03:56:45 -0800 (PST) Received: from kwepemm600003.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4PGxJF6NtszFqPf; Wed, 15 Feb 2023 19:51:57 +0800 (CST) Received: from ubuntu1804.huawei.com (10.67.174.61) by kwepemm600003.china.huawei.com (7.193.23.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Wed, 15 Feb 2023 19:56:41 +0800 From: Yang Jihong To: , , , , , , , , , , , , , CC: Subject: [PATCH 2/3] x86/kprobes: Fix __recover_optprobed_insn check optimizing logic Date: Wed, 15 Feb 2023 19:54:29 +0800 Message-ID: <20230215115430.236046-3-yangjihong1@huawei.com> X-Mailer: git-send-email 2.30.GIT In-Reply-To: <20230215115430.236046-1-yangjihong1@huawei.com> References: <20230215115430.236046-1-yangjihong1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.174.61] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600003.china.huawei.com (7.193.23.202) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org Since the following commit: commit f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") modified the update timing of the KPROBE_FLAG_OPTIMIZED, a optimized_kprobe may be in the optimizing or unoptimizing state when op.kp->flags has KPROBE_FLAG_OPTIMIZED and op->list is not empty. The __recover_optprobed_insn check logic is incorrect, a kprobe in the unoptimizing state may be incorrectly determined as unoptimizing. As a result, incorrect instructions are copied. The optprobe_queued_unopt function needs to be exported for invoking in arch directory. Fixes: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") Signed-off-by: Yang Jihong --- arch/x86/kernel/kprobes/opt.c | 4 ++-- include/linux/kprobes.h | 1 + kernel/kprobes.c | 2 +- 3 files changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index e57e07b0edb6..3718d6863555 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -46,8 +46,8 @@ unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsigned long addr) /* This function only handles jump-optimized kprobe */ if (kp && kprobe_optimized(kp)) { op = container_of(kp, struct optimized_kprobe, kp); - /* If op->list is not empty, op is under optimizing */ - if (list_empty(&op->list)) + /* If op is [un]optimized or under unoptimizing */ + if (list_empty(&op->list) || optprobe_queued_unopt(op)) goto found; } } diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index a0b92be98984..ab39285f71a6 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -378,6 +378,7 @@ extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); DEFINE_INSN_CACHE_OPS(optinsn); extern void wait_for_kprobe_optimizer(void); +bool optprobe_queued_unopt(struct optimized_kprobe *op); #else /* !CONFIG_OPTPROBES */ static inline void wait_for_kprobe_optimizer(void) { } #endif /* CONFIG_OPTPROBES */ diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 0730e595f4c1..bf60eb26c873 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -661,7 +661,7 @@ void wait_for_kprobe_optimizer(void) mutex_unlock(&kprobe_mutex); } -static bool optprobe_queued_unopt(struct optimized_kprobe *op) +bool optprobe_queued_unopt(struct optimized_kprobe *op) { struct optimized_kprobe *_op; From patchwork Wed Feb 15 11:54:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Jihong X-Patchwork-Id: 13141562 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03E02C6379F for ; Wed, 15 Feb 2023 11:56:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233769AbjBOL4r (ORCPT ); Wed, 15 Feb 2023 06:56:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230147AbjBOL4q (ORCPT ); Wed, 15 Feb 2023 06:56:46 -0500 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79583A264; Wed, 15 Feb 2023 03:56:44 -0800 (PST) Received: from kwepemm600003.china.huawei.com (unknown [172.30.72.54]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4PGxM16qywz16NZb; Wed, 15 Feb 2023 19:54:21 +0800 (CST) Received: from ubuntu1804.huawei.com (10.67.174.61) by kwepemm600003.china.huawei.com (7.193.23.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Wed, 15 Feb 2023 19:56:41 +0800 From: Yang Jihong To: , , , , , , , , , , , , , CC: Subject: [PATCH 3/3] x86/kprobes: Fix arch_check_optimized_kprobe check within optimized_kprobe range Date: Wed, 15 Feb 2023 19:54:30 +0800 Message-ID: <20230215115430.236046-4-yangjihong1@huawei.com> X-Mailer: git-send-email 2.30.GIT In-Reply-To: <20230215115430.236046-1-yangjihong1@huawei.com> References: <20230215115430.236046-1-yangjihong1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.174.61] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600003.china.huawei.com (7.193.23.202) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org When arch_prepare_optimized_kprobe calculating jump destination address, it copies original instructions from jmp-optimized kprobe (see __recover_optprobed_insn), and calculated based on length of original instruction. arch_check_optimized_kprobe does not check KPROBE_FLAG_OPTIMATED when checking whether jmp-optimized kprobe exists. As a result, setup_detour_execution may jump to a range that has been overwritten by jump destination address, resulting in an inval opcode error. For example, assume that register two kprobes whose addresses are and in "func" function. The original code of "func" function is as follows: 0xffffffff816cb5e9 <+9>: push %r12 0xffffffff816cb5eb <+11>: xor %r12d,%r12d 0xffffffff816cb5ee <+14>: test %rdi,%rdi 0xffffffff816cb5f1 <+17>: setne %r12b 0xffffffff816cb5f5 <+21>: push %rbp 1.Register the kprobe for , assume that is kp1, corresponding optimized_kprobe is op1. After the optimization, "func" code changes to: 0xffffffff816cc079 <+9>: push %r12 0xffffffff816cc07b <+11>: jmp 0xffffffffa0210000 0xffffffff816cc080 <+16>: incl 0xf(%rcx) 0xffffffff816cc083 <+19>: xchg %eax,%ebp 0xffffffff816cc084 <+20>: (bad) 0xffffffff816cc085 <+21>: push %rbp Now op1->flags == KPROBE_FLAG_OPTIMATED; 2. Register the kprobe for , assume that is kp2, corresponding optimized_kprobe is op2. register_kprobe(kp2) register_aggr_kprobe alloc_aggr_kprobe __prepare_optimized_kprobe arch_prepare_optimized_kprobe __recover_optprobed_insn // copy original bytes from kp1->optinsn.copied_insn, // jump address = 3. disable kp1: disable_kprobe(kp1) __disable_kprobe ... if (p == orig_p || aggr_kprobe_disabled(orig_p)) { ret = disarm_kprobe(orig_p, true) // add op1 in unoptimizing_list, not unoptimized orig_p->flags |= KPROBE_FLAG_DISABLED; // op1->flags == KPROBE_FLAG_OPTIMATED | KPROBE_FLAG_DISABLED ... 4. unregister kp2 __unregister_kprobe_top ... if (!kprobe_disabled(ap) && !kprobes_all_disarmed) { optimize_kprobe(op) ... if (arch_check_optimized_kprobe(op) < 0) // because op1 has KPROBE_FLAG_DISABLED, here not return return; p->kp.flags |= KPROBE_FLAG_OPTIMIZED; // now op2 has KPROBE_FLAG_OPTIMIZED } "func" code now is: 0xffffffff816cc079 <+9>: int3 0xffffffff816cc07a <+10>: push %rsp 0xffffffff816cc07b <+11>: jmp 0xffffffffa0210000 0xffffffff816cc080 <+16>: incl 0xf(%rcx) 0xffffffff816cc083 <+19>: xchg %eax,%ebp 0xffffffff816cc084 <+20>: (bad) 0xffffffff816cc085 <+21>: push %rbp 5. if call "func", int3 handler call setup_detour_execution: if (p->flags & KPROBE_FLAG_OPTIMIZED) { ... regs->ip = (unsigned long)op->optinsn.insn + TMPL_END_IDX; ... } The code for the destination address is 0xffffffffa021072c: push %r12 0xffffffffa021072e: xor %r12d,%r12d 0xffffffffa0210731: jmp 0xffffffff816cb5ee However, is not a valid start instruction address. As a result, an error occurs. Signed-off-by: Yang Jihong --- arch/x86/kernel/kprobes/opt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 3718d6863555..e6d9bd038401 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -353,7 +353,7 @@ int arch_check_optimized_kprobe(struct optimized_kprobe *op) for (i = 1; i < op->optinsn.size; i++) { p = get_kprobe(op->kp.addr + i); - if (p && !kprobe_disabled(p)) + if (p && (!kprobe_disabled(p) || kprobe_optimized(p))) return -EEXIST; }