140 lines
4.4 KiB
Diff
140 lines
4.4 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, 4 Dec 2017 15:08:05 +0100
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Subject: [PATCH] x86/mm/dump_pagetables: Check user space page table for WX
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pages
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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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ptdump_walk_pgd_level_checkwx() checks the kernel page table for WX pages,
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but does not check the PAGE_TABLE_ISOLATION user space page table.
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Restructure the code so that dmesg output is selected by an explicit
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argument and not implicit via checking the pgd argument for !NULL.
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Add the check for the user space page table.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: Andy Lutomirski <luto@kernel.org>
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Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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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: Dave Hansen <dave.hansen@linux.intel.com>
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Cc: David Laight <David.Laight@aculab.com>
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Cc: Denys Vlasenko <dvlasenk@redhat.com>
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Cc: Eduardo Valentin <eduval@amazon.com>
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Cc: Greg KH <gregkh@linuxfoundation.org>
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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: Will Deacon <will.deacon@arm.com>
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Cc: aliguori@amazon.com
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Cc: daniel.gruss@iaik.tugraz.at
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Cc: hughd@google.com
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Cc: keescook@google.com
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Cc: linux-mm@kvack.org
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit b4bf4f924b1d7bade38fd51b2e401d20d0956e4d)
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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 1adfe82e8fe5afa2fae59efe498c461d5a52cb6c)
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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/pgtable.h | 1 +
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arch/x86/mm/debug_pagetables.c | 2 +-
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arch/x86/mm/dump_pagetables.c | 30 +++++++++++++++++++++++++-----
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3 files changed, 27 insertions(+), 6 deletions(-)
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diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
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index 25604b8a251a..4f5eb81cf8be 100644
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--- a/arch/x86/include/asm/pgtable.h
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+++ b/arch/x86/include/asm/pgtable.h
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@@ -17,6 +17,7 @@
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#include <asm/x86_init.h>
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void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd);
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+void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd);
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void ptdump_walk_pgd_level_checkwx(void);
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#ifdef CONFIG_DEBUG_WX
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diff --git a/arch/x86/mm/debug_pagetables.c b/arch/x86/mm/debug_pagetables.c
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index d1449fb6dc7a..8e70c1599e51 100644
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--- a/arch/x86/mm/debug_pagetables.c
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+++ b/arch/x86/mm/debug_pagetables.c
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@@ -5,7 +5,7 @@
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static int ptdump_show(struct seq_file *m, void *v)
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{
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- ptdump_walk_pgd_level(m, NULL);
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+ ptdump_walk_pgd_level_debugfs(m, NULL);
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return 0;
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}
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diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
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index eed93dd4cb4a..7b022ad37c4e 100644
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--- a/arch/x86/mm/dump_pagetables.c
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+++ b/arch/x86/mm/dump_pagetables.c
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@@ -457,7 +457,7 @@ static inline bool is_hypervisor_range(int idx)
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}
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static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
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- bool checkwx)
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+ bool checkwx, bool dmesg)
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{
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#ifdef CONFIG_X86_64
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pgd_t *start = (pgd_t *) &init_top_pgt;
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@@ -470,7 +470,7 @@ static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
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if (pgd) {
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start = pgd;
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- st.to_dmesg = true;
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+ st.to_dmesg = dmesg;
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}
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st.check_wx = checkwx;
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@@ -508,13 +508,33 @@ static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
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void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
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{
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- ptdump_walk_pgd_level_core(m, pgd, false);
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+ ptdump_walk_pgd_level_core(m, pgd, false, true);
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+}
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+
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+void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd)
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+{
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+ ptdump_walk_pgd_level_core(m, pgd, false, false);
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+}
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+EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level_debugfs);
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+
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+static void ptdump_walk_user_pgd_level_checkwx(void)
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+{
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+#ifdef CONFIG_PAGE_TABLE_ISOLATION
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+ pgd_t *pgd = (pgd_t *) &init_top_pgt;
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+
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+ if (!static_cpu_has(X86_FEATURE_PTI))
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+ return;
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+
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+ pr_info("x86/mm: Checking user space page tables\n");
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+ pgd = kernel_to_user_pgdp(pgd);
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+ ptdump_walk_pgd_level_core(NULL, pgd, true, false);
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+#endif
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}
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-EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level);
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void ptdump_walk_pgd_level_checkwx(void)
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{
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- ptdump_walk_pgd_level_core(NULL, NULL, true);
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+ ptdump_walk_pgd_level_core(NULL, NULL, true, false);
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+ ptdump_walk_user_pgd_level_checkwx();
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}
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static int __init pt_dump_init(void)
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--
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2.14.2
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