linux-kernel - [PATCH 1/6] KVM: x86: bit-ops emulation ignores offset on 64-bit

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Sun, 15 Jun 2014 16:12:57 +0300
From:	Nadav Amit <namit@...technion.ac.il>
To:	pbonzini@...hat.com
Cc:	gleb@...nel.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Nadav Amit <namit@...technion.ac.il>
Subject: [PATCH 1/6] KVM: x86: bit-ops emulation ignores offset on 64-bit

The current emulation of bit operations ignores the offset from the destination
on 64-bit target memory operands. This patch fixes this behavior.

Signed-off-by: Nadav Amit <namit@...technion.ac.il>
---
 arch/x86/kvm/emulate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index e4e833d..f0b0a10 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1220,12 +1220,14 @@ static void fetch_bit_operand(struct x86_emulate_ctxt *ctxt)
 	long sv = 0, mask;
 
 	if (ctxt->dst.type == OP_MEM && ctxt->src.type == OP_REG) {
-		mask = ~(ctxt->dst.bytes * 8 - 1);
+		mask = ~((long)ctxt->dst.bytes * 8 - 1);
 
 		if (ctxt->src.bytes == 2)
 			sv = (s16)ctxt->src.val & (s16)mask;
 		else if (ctxt->src.bytes == 4)
 			sv = (s32)ctxt->src.val & (s32)mask;
+		else
+			sv = (s64)ctxt->src.val & (s64)mask;
 
 		ctxt->dst.addr.mem.ea += (sv >> 3);
 	}
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/