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From: tip-bot for Masami Hiramatsu <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: mhiramat@kernel.org, yhs@fb.com, torvalds@linux-foundation.org,
	bp@suse.de, luto@kernel.org,
	ricardo.neri-calderon@linux.intel.com,
	linux-kernel@vger.kernel.org, oleg@redhat.com, mingo@kernel.org,
	francis.deslauriers@efficios.com, rostedt@goodmis.org,
	ast@kernel.org, hpa@zytor.com, tglx@linutronix.de,
	davem@davemloft.net
Subject: [tip:x86/urgent] uprobes/x86: Prohibit probing on MOV SS instruction
Date: Sun, 13 May 2018 10:58:17 -0700	[thread overview]
Message-ID: <tip-13ebe18c94f5b0665c01ae7fad2717ae959f4212@git.kernel.org> (raw)
In-Reply-To: <152587072544.17316.5950935243917346341.stgit@devbox>

Commit-ID:  13ebe18c94f5b0665c01ae7fad2717ae959f4212
Gitweb:     https://git.kernel.org/tip/13ebe18c94f5b0665c01ae7fad2717ae959f4212
Author:     Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Wed, 9 May 2018 21:58:45 +0900
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 19:52:56 +0200

uprobes/x86: Prohibit probing on MOV SS instruction

Since MOV SS and POP SS instructions will delay the exceptions until the
next instruction is executed, single-stepping on it by uprobes must be
prohibited.

uprobe already rejects probing on POP SS (0x1f), but allows probing on MOV
SS (0x8e and reg == 2).  This checks the target instruction and if it is
MOV SS or POP SS, returns -ENOTSUPP to reject probing.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Francis Deslauriers <francis.deslauriers@efficios.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "David S . Miller" <davem@davemloft.net>
Link: https://lkml.kernel.org/r/152587072544.17316.5950935243917346341.stgit@devbox

---
 arch/x86/kernel/uprobes.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 85c7ef23d99f..c84bb5396958 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -299,6 +299,10 @@ static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool
 	if (is_prefix_bad(insn))
 		return -ENOTSUPP;
 
+	/* We should not singlestep on the exception masking instructions */
+	if (insn_masking_exception(insn))
+		return -ENOTSUPP;
+
 	if (x86_64)
 		good_insns = good_insns_64;
 	else

  parent reply	other threads:[~2018-05-13 17:59 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-09 12:57 [PATCH 0/2] uprobes: x86: Reject probing MOV SS Masami Hiramatsu
2018-05-09 12:58 ` [PATCH 1/2] kprobes: x86: Prohibit probing on exception masking instructions Masami Hiramatsu
2018-05-13 17:57   ` [tip:x86/urgent] kprobes/x86: " tip-bot for Masami Hiramatsu
2018-05-09 12:58 ` [PATCH 2/2] uprobes: x86: Prohibit probing on MOV SS instruction Masami Hiramatsu
2018-05-09 16:39   ` Oleg Nesterov
2018-05-13 17:58   ` tip-bot for Masami Hiramatsu [this message]
2018-05-09 13:01 ` [PATCH 0/2] uprobes: kprobes: x86: Reject probing MOV SS/POP SS Masami Hiramatsu
2018-05-09 14:36 ` [PATCH 0/2] uprobes: x86: Reject probing MOV SS Andy Lutomirski
2018-05-09 22:25   ` Masami Hiramatsu

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