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From: Chen Guokai <chenguokai17@mails.ucas.ac.cn>
To: paul.walmsley@sifive.com, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, rostedt@goodmis.org, mingo@redhat.com,
	sfr@canb.auug.org.au
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	liaochang1@huawei.com
Subject: [PATCH v6 10/13] riscv/kprobe: Add instruction boundary check for RVI/RVC hybrid kernel
Date: Fri, 27 Jan 2023 21:05:38 +0800	[thread overview]
Message-ID: <20230127130541.1250865-11-chenguokai17@mails.ucas.ac.cn> (raw)
In-Reply-To: <20230127130541.1250865-1-chenguokai17@mails.ucas.ac.cn>

From: Liao Chang <liaochang1@huawei.com>

Add instruction boundary check to ensure kprobe doesn't truncate any RVI
instruction, which leads to kernel crash.

Signed-off-by: Liao Chang <liaochang1@huawei.com>
---
 arch/riscv/kernel/probes/kprobes.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index e1856b04db04..91a6b46909cc 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -49,11 +49,33 @@ static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
 	post_kprobe_handler(p, kcb, regs);
 }
 
+bool __kprobes riscv_insn_boundary_check(unsigned long paddr)
+{
+#if defined(CONFIG_RISCV_ISA_C)
+	unsigned long size = 0, offs = 0, len = 0, entry = 0;
+
+	if (!kallsyms_lookup_size_offset(paddr, &size, &offs))
+		return false;
+
+	/*
+	 * Scan instructions from function entry ensure the kprobe address
+	 * is aligned with RVI or RVC boundary.
+	 */
+	entry = paddr - offs;
+	while ((entry + len) < paddr)
+		len += GET_INSN_LENGTH(*(kprobe_opcode_t *)(entry + len));
+	return (entry + len) == paddr;
+#else
+	return true;
+#endif
+}
+
 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
 	unsigned long probe_addr = (unsigned long)p->addr;
 
-	if (probe_addr & 0x1)
+	/* for RVI/RCV hybrid kernel, it needs instruction boundary check */
+	if ((probe_addr & 0x1) || !riscv_insn_boundary_check(probe_addr))
 		return -EILSEQ;
 
 	/* copy instruction */
-- 
2.34.1


  parent reply	other threads:[~2023-01-27 13:06 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-27 13:05 [PATCH v6 00/13] Add OPTPROBES feature on RISCV Chen Guokai
2023-01-27 13:05 ` [PATCH v6 01/13] riscv/kprobe: Prepare the skeleton to implement RISCV OPTPROBES Chen Guokai
2023-01-27 13:05 ` [PATCH v6 02/13] riscv/kprobe: Allocate detour buffer from module region Chen Guokai
2023-01-27 13:05 ` [PATCH v6 03/13] riscv/kprobe: Add skeleton for preparing optimized kprobe Chen Guokai
2023-01-27 13:05 ` [PATCH v6 04/13] riscv/kprobe: Add common RVI and RVC instruction decoder code Chen Guokai
2023-02-01 13:29   ` Björn Töpel
2023-02-02 10:16   ` Conor Dooley
2023-01-27 13:05 ` [PATCH v6 05/13] riscv/kprobe: Introduce free register(s) searching algorithm Chen Guokai
2023-01-27 13:05 ` [PATCH v6 06/13] riscv/kprobe: Add code to check if kprobe can be optimized Chen Guokai
2023-02-01 13:30   ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 07/13] riscv/kprobe: Prepare detour buffer for optimized kprobe Chen Guokai
2023-02-01 13:30   ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 08/13] riscv/kprobe: Patch AUIPC/JALR pair to optimize kprobe Chen Guokai
2023-02-01 13:31   ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 09/13] riscv/kprobe: Search free registers from unused caller-saved ones Chen Guokai
2023-02-01 13:31   ` Björn Töpel
2023-02-02  9:08   ` Conor Dooley
2023-01-27 13:05 ` Chen Guokai [this message]
2023-01-27 13:05 ` [PATCH v6 11/13] riscv/kprobe: Fix instruction simulation of JALR Chen Guokai
2023-01-31 12:51   ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 12/13] riscv/kprobe: Move exception related symbols to .kprobe_blacklist Chen Guokai
2023-02-01 13:30   ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 13/13] selftest/kprobes: Add testcase for kprobe SYM[+offs] Chen Guokai
2023-01-30 12:31 ` [PATCH v6 00/13] Add OPTPROBES feature on RISCV Björn Töpel
2023-01-30 14:38   ` Xim
2023-04-26 18:01     ` Palmer Dabbelt
2023-02-01 13:29 ` Björn Töpel

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