From: Masami Hiramatsu <mhiramat@kernel.org>
To: x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>
Cc: Kees Cook <keescook@chromium.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
"H . Peter Anvin" <hpa@zytor.com>, Joerg Roedel <jroedel@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>,
"Gustavo A . R . Silva" <gustavoars@kernel.org>,
Jann Horn <jannh@google.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/3] x86/uprobes: Fix not using prefixes.nbytes for loop over prefixes.bytes
Date: Wed, 2 Dec 2020 17:51:16 +0900 [thread overview]
Message-ID: <160689907597.3084105.18019089399087866918.stgit@devnote2> (raw)
In-Reply-To: <160689905099.3084105.7880450206184269465.stgit@devnote2>
Since the insn.prefixes.nbytes can be bigger than the size of
insn.prefixes.bytes[] when a same prefix is repeated, we have to
check whether the insn.prefixes.bytes[i] != 0 and i < 4 instead
of insn.prefixes.nbytes.
Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints")
Cc: stable@vger.kernel.org
Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/x86/kernel/uprobes.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 3fdaa042823d..bb3ea3705b99 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -257,7 +257,7 @@ static bool is_prefix_bad(struct insn *insn)
{
int i;
- for (i = 0; i < insn->prefixes.nbytes; i++) {
+ for (i = 0; insn->prefixes.bytes[i] && i < 4; i++) {
insn_attr_t attr;
attr = inat_get_opcode_attribute(insn->prefixes.bytes[i]);
@@ -746,7 +746,7 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn)
* Intel and AMD behavior differ in 64-bit mode: Intel ignores 66 prefix.
* No one uses these insns, reject any branch insns with such prefix.
*/
- for (i = 0; i < insn->prefixes.nbytes; i++) {
+ for (i = 0; insn->prefixes.bytes[i] && i < 4; i++) {
if (insn->prefixes.bytes[i] == 0x66)
return -ENOTSUPP;
}
next prev parent reply other threads:[~2020-12-02 8:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 8:50 [PATCH 0/3] x86/insn: Fix not using prefixes.nbytes for loop over prefixes.bytes Masami Hiramatsu
2020-12-02 8:51 ` [PATCH 1/3] x86/sev-es: " Masami Hiramatsu
2020-12-02 15:31 ` Tom Lendacky
2020-12-02 19:07 ` Kees Cook
2020-12-03 2:03 ` Masami Hiramatsu
2020-12-02 8:51 ` Masami Hiramatsu [this message]
2020-12-02 14:51 ` [PATCH 2/3] x86/uprobes: " Srikar Dronamraju
2020-12-03 4:20 ` Masami Hiramatsu
2020-12-02 19:04 ` Kees Cook
2020-12-03 2:00 ` Masami Hiramatsu
2020-12-02 8:51 ` [PATCH 3/3] x86/insn-eval: " Masami Hiramatsu
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