From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 844CC17BB04; Wed, 3 Jul 2024 11:16:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720005364; cv=none; b=IZxgFAyTERhbY7HxZFeONH3u/FnvsoLN7YkjEhnU/SaMd5G16jThuIQYvIFHWBGlhocX6qAAeD8f5wc5Kspn/NZCeSnbCgNz1FgboT50O9lbLab8i80sB+igvAn9oL2H3MbyrOm7dX40fY1wLdcUFi4FLPdIF5wRdvg42QbvxWk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720005364; c=relaxed/simple; bh=0jg3Q0tC/ZQF0B8kfAYxPSrTs2snOWNjWVq0ZsIUwk0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LpmLPP3QoC62HdmaOGvXMlfKNJAW16fGKpS+h3UDcoxInoMw+iwXNvSdIfOguHRn1i7hcMcHsYsxnho5r8dOEq3MB/CKTMAB93vj8AL6ypvKxFRMJ0OmOEVj6YAmgZxnDR3YNjMnz0FDPkyvFDouEgdJzSQTTCD8vXboJidbLIc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qMysGY9C; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qMysGY9C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07C42C2BD10; Wed, 3 Jul 2024 11:16:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1720005364; bh=0jg3Q0tC/ZQF0B8kfAYxPSrTs2snOWNjWVq0ZsIUwk0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qMysGY9C75awxw6uRIBLDLtnDmVBpDVyfXQgr3j7wyPcJyVlEO0WJLCwouxmuWtlT CoK8wnohpGQCZl4ni5IexZBbE2hzttEp4tcyzla5aRYywDoHfbuuBhqNymUvAeo31t nJJSs1Ls2TxeHtCTo0dkubCb3rNqiLJ3kGH+JU2E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Steven Rostedt , "Peter Zijlstra (Intel)" , Masami Hiramatsu , Josh Poimboeuf , Sasha Levin Subject: [PATCH 5.15 057/356] x86/ibt,ftrace: Search for __fentry__ location Date: Wed, 3 Jul 2024 12:36:33 +0200 Message-ID: <20240703102915.252024365@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240703102913.093882413@linuxfoundation.org> References: <20240703102913.093882413@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra [ Upstream commit aebfd12521d9c7d0b502cf6d06314cfbcdccfe3b ] Currently a lot of ftrace code assumes __fentry__ is at sym+0. However with Intel IBT enabled the first instruction of a function will most likely be ENDBR. Change ftrace_location() to not only return the __fentry__ location when called for the __fentry__ location, but also when called for the sym+0 location. Then audit/update all callsites of this function to consistently use these new semantics. Suggested-by: Steven Rostedt Signed-off-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220308154318.227581603@infradead.org Stable-dep-of: e60b613df8b6 ("ftrace: Fix possible use-after-free issue in ftrace_location()") Signed-off-by: Sasha Levin --- arch/x86/kernel/kprobes/core.c | 11 ++------ kernel/bpf/trampoline.c | 20 +++----------- kernel/kprobes.c | 8 ++---- kernel/trace/ftrace.c | 48 ++++++++++++++++++++++++++++------ 4 files changed, 48 insertions(+), 39 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 893f040b97b7d..99dd504307fdc 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -194,17 +194,10 @@ static unsigned long __recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr) { struct kprobe *kp; - unsigned long faddr; + bool faddr; kp = get_kprobe((void *)addr); - faddr = ftrace_location(addr); - /* - * Addresses inside the ftrace location are refused by - * arch_check_ftrace_location(). Something went terribly wrong - * if such an address is checked here. - */ - if (WARN_ON(faddr && faddr != addr)) - return 0UL; + faddr = ftrace_location(addr) == addr; /* * Use the current code if it is not modified by Kprobe * and it cannot be modified by ftrace. diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 4fa75791b45e2..1bffee0458863 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -108,18 +108,6 @@ static void bpf_trampoline_module_put(struct bpf_trampoline *tr) tr->mod = NULL; } -static int is_ftrace_location(void *ip) -{ - long addr; - - addr = ftrace_location((long)ip); - if (!addr) - return 0; - if (WARN_ON_ONCE(addr != (long)ip)) - return -EFAULT; - return 1; -} - static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr) { void *ip = tr->func.addr; @@ -151,12 +139,12 @@ static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_ad static int register_fentry(struct bpf_trampoline *tr, void *new_addr) { void *ip = tr->func.addr; + unsigned long faddr; int ret; - ret = is_ftrace_location(ip); - if (ret < 0) - return ret; - tr->func.ftrace_managed = ret; + faddr = ftrace_location((unsigned long)ip); + if (faddr) + tr->func.ftrace_managed = true; if (bpf_trampoline_module_get(tr)) return -ENOENT; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index af57705e1fef3..258d425b2c4a5 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1526,14 +1526,10 @@ static inline int warn_kprobe_rereg(struct kprobe *p) int __weak arch_check_ftrace_location(struct kprobe *p) { - unsigned long ftrace_addr; + unsigned long addr = (unsigned long)p->addr; - ftrace_addr = ftrace_location((unsigned long)p->addr); - if (ftrace_addr) { + if (ftrace_location(addr) == addr) { #ifdef CONFIG_KPROBES_ON_FTRACE - /* Given address is not on the instruction boundary */ - if ((unsigned long)p->addr != ftrace_addr) - return -EILSEQ; p->flags |= KPROBE_FLAG_FTRACE; #else /* !CONFIG_KPROBES_ON_FTRACE */ return -EINVAL; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 157a1d2d9802f..3dce1a107a7c7 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1575,17 +1575,34 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end) } /** - * ftrace_location - return true if the ip giving is a traced location + * ftrace_location - return the ftrace location * @ip: the instruction pointer to check * - * Returns rec->ip if @ip given is a pointer to a ftrace location. - * That is, the instruction that is either a NOP or call to - * the function tracer. It checks the ftrace internal tables to - * determine if the address belongs or not. + * If @ip matches the ftrace location, return @ip. + * If @ip matches sym+0, return sym's ftrace location. + * Otherwise, return 0. */ unsigned long ftrace_location(unsigned long ip) { - return ftrace_location_range(ip, ip); + struct dyn_ftrace *rec; + unsigned long offset; + unsigned long size; + + rec = lookup_rec(ip, ip); + if (!rec) { + if (!kallsyms_lookup_size_offset(ip, &size, &offset)) + goto out; + + /* map sym+0 to __fentry__ */ + if (!offset) + rec = lookup_rec(ip, ip + size - 1); + } + + if (rec) + return rec->ip; + +out: + return 0; } /** @@ -4942,7 +4959,8 @@ ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove) { struct ftrace_func_entry *entry; - if (!ftrace_location(ip)) + ip = ftrace_location(ip); + if (!ip) return -EINVAL; if (remove) { @@ -5090,11 +5108,16 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr) struct ftrace_func_entry *entry; struct ftrace_hash *free_hash = NULL; struct dyn_ftrace *rec; - int ret = -EBUSY; + int ret = -ENODEV; mutex_lock(&direct_mutex); + ip = ftrace_location(ip); + if (!ip) + goto out_unlock; + /* See if there's a direct function at @ip already */ + ret = -EBUSY; if (ftrace_find_rec_direct(ip)) goto out_unlock; @@ -5223,6 +5246,10 @@ int unregister_ftrace_direct(unsigned long ip, unsigned long addr) mutex_lock(&direct_mutex); + ip = ftrace_location(ip); + if (!ip) + goto out_unlock; + entry = find_direct_entry(&ip, NULL); if (!entry) goto out_unlock; @@ -5354,6 +5381,11 @@ int modify_ftrace_direct(unsigned long ip, mutex_lock(&direct_mutex); mutex_lock(&ftrace_lock); + + ip = ftrace_location(ip); + if (!ip) + goto out_unlock; + entry = find_direct_entry(&ip, &rec); if (!entry) goto out_unlock; -- 2.43.0