linux-kernel - [PATCH v3 07/10] x86/umip: Avoid crossing the page boundary

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5bb84bce0c798a76a318a38e1bb827af10ecaefd.1723807851.git.legion@kernel.org>
Date: Fri, 16 Aug 2024 15:43:57 +0200
From: Alexey Gladkov <legion@...nel.org>
To: linux-kernel@...r.kernel.org,
	linux-coco@...ts.linux.dev
Cc: "Alexey Gladkov (Intel)" <legion@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Yuan Yao <yuan.yao@...el.com>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Yuntao Wang <ytcoode@...il.com>,
	Kai Huang <kai.huang@...el.com>,
	Baoquan He <bhe@...hat.com>,
	Oleg Nesterov <oleg@...hat.com>,
	cho@...rosoft.com,
	decui@...rosoft.com,
	John.Starks@...rosoft.com
Subject: [PATCH v3 07/10] x86/umip: Avoid crossing the page boundary

From: "Alexey Gladkov (Intel)" <legion@...nel.org>

Try to avoid crossing the page boundary to avoid side effects if the
next page belongs to another VMA.

Signed-off-by: Alexey Gladkov (Intel) <legion@...nel.org>
---
 arch/x86/kernel/umip.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c
index 5a4b21389b1d..e85c3cafc258 100644
--- a/arch/x86/kernel/umip.c
+++ b/arch/x86/kernel/umip.c
@@ -338,7 +338,6 @@ bool fixup_umip_exception(struct pt_regs *regs)
 	int nr_copied, reg_offset, dummy_data_size, umip_inst;
 	/* 10 bytes is the maximum size of the result of UMIP instructions */
 	unsigned char dummy_data[10] = { 0 };
-	unsigned char buf[MAX_INSN_SIZE];
 	unsigned long *reg_addr;
 	void __user *uaddr;
 	struct insn insn;
@@ -350,11 +349,7 @@ bool fixup_umip_exception(struct pt_regs *regs)
 	 * Give up on emulation if fetching the instruction failed. Should a
 	 * page fault or a #GP be issued?
 	 */
-	nr_copied = insn_fetch_from_user(regs, buf);
-	if (nr_copied <= 0)
-		return false;
-
-	if (!insn_decode_from_regs(&insn, regs, buf, nr_copied))
+	if (insn_fetch_decode_from_user(&insn, regs))
 		return false;
 
 	umip_inst = identify_insn(&insn);
-- 
2.45.2