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]
Message-Id: <1617140178-8773-22-git-send-email-anthony.yznaga@oracle.com>
Date:   Tue, 30 Mar 2021 14:35:56 -0700
From:   Anthony Yznaga <anthony.yznaga@...cle.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     willy@...radead.org, corbet@....net, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, x86@...nel.org, hpa@...or.com,
        dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
        rppt@...nel.org, akpm@...ux-foundation.org, hughd@...gle.com,
        ebiederm@...ssion.com, keescook@...omium.org, ardb@...nel.org,
        nivedita@...m.mit.edu, jroedel@...e.de, masahiroy@...nel.org,
        nathan@...nel.org, terrelln@...com, vincenzo.frascino@....com,
        martin.b.radev@...il.com, andreyknvl@...gle.com,
        daniel.kiper@...cle.com, rafael.j.wysocki@...el.com,
        dan.j.williams@...el.com, Jonathan.Cameron@...wei.com,
        bhe@...hat.com, rminnich@...il.com, ashish.kalra@....com,
        guro@...com, hannes@...xchg.org, mhocko@...nel.org,
        iamjoonsoo.kim@....com, vbabka@...e.cz, alex.shi@...ux.alibaba.com,
        david@...hat.com, richard.weiyang@...il.com,
        vdavydov.dev@...il.com, graf@...zon.com, jason.zeng@...el.com,
        lei.l.li@...el.com, daniel.m.jordan@...cle.com,
        steven.sistare@...cle.com, linux-fsdevel@...r.kernel.org,
        linux-doc@...r.kernel.org, kexec@...ts.infradead.org
Subject: [RFC v2 21/43] x86/KASLR: PKRAM: support physical kaslr

Avoid regions of memory that contain preserved pages when computing
slots used to select where to put the decompressed kernel.

Signed-off-by: Anthony Yznaga <anthony.yznaga@...cle.com>
---
 arch/x86/boot/compressed/Makefile |   3 ++
 arch/x86/boot/compressed/kaslr.c  |  10 +++-
 arch/x86/boot/compressed/misc.h   |  10 ++++
 arch/x86/boot/compressed/pkram.c  | 109 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 130 insertions(+), 2 deletions(-)
 create mode 100644 arch/x86/boot/compressed/pkram.c

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index e0bc3988c3fa..ef27d411b641 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -93,6 +93,9 @@ ifdef CONFIG_X86_64
 	vmlinux-objs-y += $(obj)/mem_encrypt.o
 	vmlinux-objs-y += $(obj)/pgtable_64.o
 	vmlinux-objs-$(CONFIG_AMD_MEM_ENCRYPT) += $(obj)/sev-es.o
+ifdef CONFIG_RANDOMIZE_BASE
+	vmlinux-objs-$(CONFIG_PKRAM) += $(obj)/pkram.o
+endif
 endif
 
 vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index b92fffbe761f..a007363a7698 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -440,6 +440,7 @@ static bool mem_avoid_overlap(struct mem_vector *img,
 	struct setup_data *ptr;
 	u64 earliest = img->start + img->size;
 	bool is_overlapping = false;
+	struct mem_vector avoid;
 
 	for (i = 0; i < MEM_AVOID_MAX; i++) {
 		if (mem_overlaps(img, &mem_avoid[i]) &&
@@ -453,8 +454,6 @@ static bool mem_avoid_overlap(struct mem_vector *img,
 	/* Avoid all entries in the setup_data linked list. */
 	ptr = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
 	while (ptr) {
-		struct mem_vector avoid;
-
 		avoid.start = (unsigned long)ptr;
 		avoid.size = sizeof(*ptr) + ptr->len;
 
@@ -479,6 +478,12 @@ static bool mem_avoid_overlap(struct mem_vector *img,
 		ptr = (struct setup_data *)(unsigned long)ptr->next;
 	}
 
+	if (pkram_has_overlap(img, &avoid) && (avoid.start < earliest)) {
+		*overlap = avoid;
+		earliest = overlap->start;
+		is_overlapping = true;
+	}
+
 	return is_overlapping;
 }
 
@@ -840,6 +845,7 @@ void choose_random_location(unsigned long input,
 		return;
 	}
 
+	pkram_init();
 	boot_params->hdr.loadflags |= KASLR_FLAG;
 
 	if (IS_ENABLED(CONFIG_X86_32))
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 901ea5ebec22..f8232ffd8141 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -116,6 +116,16 @@ static inline void console_init(void)
 { }
 #endif
 
+#ifdef CONFIG_PKRAM
+void pkram_init(void);
+int pkram_has_overlap(struct mem_vector *entry, struct mem_vector *overlap);
+#else
+static inline void pkram_init(void) { }
+static inline int pkram_has_overlap(struct mem_vector *entry,
+				    struct mem_vector *overlap);
+{ return 0; }
+#endif
+
 void set_sev_encryption_mask(void);
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
diff --git a/arch/x86/boot/compressed/pkram.c b/arch/x86/boot/compressed/pkram.c
new file mode 100644
index 000000000000..60380f074c3f
--- /dev/null
+++ b/arch/x86/boot/compressed/pkram.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "misc.h"
+
+#define PKRAM_MAGIC		0x706B726D
+
+struct pkram_super_block {
+	__u32	magic;
+
+	__u64	node_pfn;
+	__u64	region_list_pfn;
+	__u64	nr_regions;
+};
+
+struct pkram_region {
+	phys_addr_t base;
+	phys_addr_t size;
+};
+
+struct pkram_region_list {
+	__u64	prev_pfn;
+	__u64	next_pfn;
+
+	struct pkram_region regions[0];
+};
+
+#define PKRAM_REGIONS_LIST_MAX \
+	((PAGE_SIZE-sizeof(struct pkram_region_list))/sizeof(struct pkram_region))
+
+static u64 pkram_sb_pfn;
+static struct pkram_super_block *pkram_sb;
+
+void pkram_init(void)
+{
+	struct pkram_super_block *sb;
+	char arg[32];
+
+	if (cmdline_find_option("pkram", arg, sizeof(arg)) > 0) {
+		if (kstrtoull(arg, 16, &pkram_sb_pfn) != 0)
+			return;
+	} else
+		return;
+
+	sb = (struct pkram_super_block *)(pkram_sb_pfn << PAGE_SHIFT);
+	if (sb->magic != PKRAM_MAGIC) {
+		debug_putstr("PKRAM: invalid super block\n");
+		return;
+	}
+
+	pkram_sb = sb;
+}
+
+static struct pkram_region *pkram_first_region(struct pkram_super_block *sb, struct pkram_region_list **rlp, int *idx)
+{
+	if (!sb || !sb->region_list_pfn)
+		return NULL;
+
+	*rlp = (struct pkram_region_list *)(sb->region_list_pfn << PAGE_SHIFT);
+	*idx = 0;
+
+	return &(*rlp)->regions[0];
+}
+
+static struct pkram_region *pkram_next_region(struct pkram_region_list **rlp, int *idx)
+{
+	struct pkram_region_list *rl = *rlp;
+	int i = *idx;
+
+	i++;
+	if (i >= PKRAM_REGIONS_LIST_MAX) {
+		if (!rl->next_pfn) {
+			debug_putstr("PKRAM: no more pkram_region_list pages\n");
+			return NULL;
+		}
+		rl = (struct pkram_region_list *)(rl->next_pfn << PAGE_SHIFT);
+		*rlp = rl;
+		i = 0;
+	}
+	*idx = i;
+
+	if (rl->regions[i].size == 0)
+		return NULL;
+
+	return &rl->regions[i];
+}
+
+int pkram_has_overlap(struct mem_vector *entry, struct mem_vector *overlap)
+{
+	struct pkram_region_list *rl;
+	struct pkram_region *r;
+	int idx;
+
+	r = pkram_first_region(pkram_sb, &rl, &idx);
+
+	while (r) {
+		if (r->base + r->size <= entry->start) {
+			r = pkram_next_region(&rl, &idx);
+			continue;
+		}
+		if (r->base >= entry->start + entry->size)
+			return 0;
+
+		overlap->start = r->base;
+		overlap->size = r->size;
+		return 1;
+	}
+
+	return 0;
+}
-- 
1.8.3.1

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ