From: "tip-bot2 for Masami Hiramatsu" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Colin Ian King <colin.king@canonical.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: x86/core] x86/kprobes: Fix to identify indirect jmp and others using range case
Date: Thu, 25 Mar 2021 11:08:47 -0000 [thread overview]
Message-ID: <161667052779.398.5074470038473644947.tip-bot2@tip-bot2> (raw)
In-Reply-To: <161666692308.1120877.4675552834049546493.stgit@devnote2>
The following commit has been merged into the x86/core branch of tip:
Commit-ID: 2f706e0e5e263c0d204e37ea496cbb0e98aac2d2
Gitweb: https://git.kernel.org/tip/2f706e0e5e263c0d204e37ea496cbb0e98aac2d2
Author: Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Thu, 25 Mar 2021 19:08:43 +09:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 25 Mar 2021 11:37:22 +01:00
x86/kprobes: Fix to identify indirect jmp and others using range case
Fix can_boost() to identify indirect jmp and others using range case
correctly.
Since the condition in switch statement is opcode & 0xf0, it can not
evaluate to 0xff case. This should be under the 0xf0 case. However,
there is no reason to use the conbinations of the bit-masked condition
and lower bit checking.
Use range case to clean up the switch statement too.
Fixes: 6256e668b7 ("x86/kprobes: Use int3 instead of debug trap for single-step")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/161666692308.1120877.4675552834049546493.stgit@devnote2
---
arch/x86/kernel/kprobes/core.c | 44 +++++++++++++++------------------
1 file changed, 20 insertions(+), 24 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 81e1432..922a6e2 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -164,32 +164,28 @@ int can_boost(struct insn *insn, void *addr)
opcode = insn->opcode.bytes[0];
- switch (opcode & 0xf0) {
- case 0x60:
- /* can't boost "bound" */
- return (opcode != 0x62);
- case 0x70:
- return 0; /* can't boost conditional jump */
- case 0x90:
- return opcode != 0x9a; /* can't boost call far */
- case 0xc0:
- /* can't boost software-interruptions */
- return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
- case 0xd0:
- /* can boost AA* and XLAT */
- return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
- case 0xe0:
- /* can boost in/out and absolute jmps */
- return ((opcode & 0x04) || opcode == 0xea);
- case 0xf0:
- /* clear and set flags are boostable */
- return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
- case 0xff:
- /* indirect jmp is boostable */
+ switch (opcode) {
+ case 0x62: /* bound */
+ case 0x70 ... 0x7f: /* Conditional jumps */
+ case 0x9a: /* Call far */
+ case 0xc0 ... 0xc1: /* Grp2 */
+ case 0xcc ... 0xce: /* software exceptions */
+ case 0xd0 ... 0xd3: /* Grp2 */
+ case 0xd6: /* (UD) */
+ case 0xd8 ... 0xdf: /* ESC */
+ case 0xe0 ... 0xe3: /* LOOP*, JCXZ */
+ case 0xe8 ... 0xe9: /* near Call, JMP */
+ case 0xeb: /* Short JMP */
+ case 0xf0 ... 0xf4: /* LOCK/REP, HLT */
+ case 0xf6 ... 0xf7: /* Grp3 */
+ case 0xfe: /* Grp4 */
+ /* ... are not boostable */
+ return 0;
+ case 0xff: /* Grp5 */
+ /* Only indirect jmp is boostable */
return X86_MODRM_REG(insn->modrm.bytes[0]) == 4;
default:
- /* call is not boostable */
- return opcode != 0x9a;
+ return 1;
}
}
prev parent reply other threads:[~2021-03-25 11:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 10:08 [PATCH -tip 0/2] x86/kprobes: Fix and cleanup can_boost() Masami Hiramatsu
2021-03-25 10:08 ` [PATCH -tip 1/2] x86/kprobes: Fix to check non boostable prefixes correctly Masami Hiramatsu
2021-03-25 11:08 ` [tip: x86/core] " tip-bot2 for Masami Hiramatsu
2021-03-25 10:08 ` [PATCH -tip 2/2] x86/kprobes: Fix to identify indirect jmp and others using range case Masami Hiramatsu
2021-03-25 11:08 ` tip-bot2 for Masami Hiramatsu [this message]
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