94 lines
3.3 KiB
Diff
94 lines
3.3 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Mon, 28 Aug 2017 08:47:40 +0200
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Subject: [PATCH] x86/asm: Replace access to desc_struct:a/b fields
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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The union inside of desc_struct which allows access to the raw u32 parts of
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the descriptors. This raw access part is about to go away.
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Replace the few code parts which access those fields.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Cc: Andy Lutomirski <luto@kernel.org>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Brian Gerst <brgerst@gmail.com>
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Cc: Denys Vlasenko <dvlasenk@redhat.com>
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Cc: H. Peter Anvin <hpa@zytor.com>
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Cc: Josh Poimboeuf <jpoimboe@redhat.com>
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Cc: Juergen Gross <jgross@suse.com>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Steven Rostedt <rostedt@goodmis.org>
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Link: http://lkml.kernel.org/r/20170828064958.120214366@linutronix.de
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 9a98e7780022aa7cd201eb8a88a4f1d607b73cde)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit 8469c76c61ea9c3b86b596352d1148bace5ea706)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/include/asm/xen/hypercall.h | 6 ++++--
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arch/x86/kernel/tls.c | 2 +-
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arch/x86/xen/enlighten_pv.c | 2 +-
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3 files changed, 6 insertions(+), 4 deletions(-)
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diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
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index 11071fcd630e..9606688caa4b 100644
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--- a/arch/x86/include/asm/xen/hypercall.h
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+++ b/arch/x86/include/asm/xen/hypercall.h
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@@ -552,6 +552,8 @@ static inline void
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MULTI_update_descriptor(struct multicall_entry *mcl, u64 maddr,
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struct desc_struct desc)
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{
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+ u32 *p = (u32 *) &desc;
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+
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mcl->op = __HYPERVISOR_update_descriptor;
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if (sizeof(maddr) == sizeof(long)) {
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mcl->args[0] = maddr;
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@@ -559,8 +561,8 @@ MULTI_update_descriptor(struct multicall_entry *mcl, u64 maddr,
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} else {
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mcl->args[0] = maddr;
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mcl->args[1] = maddr >> 32;
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- mcl->args[2] = desc.a;
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- mcl->args[3] = desc.b;
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+ mcl->args[2] = *p++;
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+ mcl->args[3] = *p;
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}
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trace_xen_mc_entry(mcl, sizeof(maddr) == sizeof(long) ? 2 : 4);
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diff --git a/arch/x86/kernel/tls.c b/arch/x86/kernel/tls.c
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index dcd699baea1b..a106b9719c58 100644
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--- a/arch/x86/kernel/tls.c
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+++ b/arch/x86/kernel/tls.c
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@@ -93,7 +93,7 @@ static void set_tls_desc(struct task_struct *p, int idx,
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while (n-- > 0) {
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if (LDT_empty(info) || LDT_zero(info)) {
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- desc->a = desc->b = 0;
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+ memset(desc, 0, sizeof(*desc));
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} else {
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fill_ldt(desc, info);
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diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
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index 49ee3315b9f7..c76f5ff4d0d7 100644
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--- a/arch/x86/xen/enlighten_pv.c
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+++ b/arch/x86/xen/enlighten_pv.c
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@@ -501,7 +501,7 @@ static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
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static inline bool desc_equal(const struct desc_struct *d1,
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const struct desc_struct *d2)
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{
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- return d1->a == d2->a && d1->b == d2->b;
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+ return !memcmp(d1, d2, sizeof(*d1));
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}
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static void load_TLS_descriptor(struct thread_struct *t,
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--
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2.14.2
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