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kmsan.c
872 lines (783 loc) · 24.2 KB
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kmsan.c
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/*
* KMSAN runtime library.
*
* Copyright (C) 2017 Google, Inc
* Author: Alexander Potapenko <glider@google.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/compiler.h>
#include <linux/console.h>
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/kmsan.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/preempt.h>
#include <linux/percpu-defs.h>
#include <linux/mm_types.h>
#include <linux/slab.h>
#include <linux/stackdepot.h>
#include <linux/stacktrace.h>
#include <linux/types.h>
#include <asm/page.h>
#include <linux/vmalloc.h>
#include <linux/mmzone.h>
#include "../slab.h"
#include "kmsan.h"
/*
* Some kernel asm() calls mention the non-existing |__force_order| variable
* in the asm constraints to preserve the order of accesses to control
* registers. KMSAN turns those mentions into actual memory accesses, therefore
* the variable is now required to link the kernel.
*/
unsigned long __force_order;
extern char __irqentry_text_end[];
extern char __irqentry_text_start[];
extern char __softirqentry_text_end[];
extern char __softirqentry_text_start[];
/*
* Dummy load and store pages to be used when the real metadata is unavailable.
* There are separate pages for loads and stores, so that every load returns a
* zero, and every store doesn't affect other stores.
*/
char dummy_load_page[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
char dummy_store_page[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
bool kmsan_ready = false;
#define KMSAN_STACK_DEPTH 64
#define MAX_CHAIN_DEPTH 7
/*
* According to Documentation/x86/kernel-stacks, kernel code can run on the
* following stacks:
* - regular task stack - when executing the task code
* - interrupt stack - when handling external hardware interrupts and softirqs
* - NMI stack
* 0 is for regular interrupts, 1 for softirqs, 2 for NMI.
* Because interrupts may nest, trying to use a new context for every new interrupt.
*/
/* [0] for dummy per-CPU context. */
DEFINE_PER_CPU(kmsan_context_state[KMSAN_NESTED_CONTEXT_MAX], kmsan_percpu_cstate);
/* 0 for task context, |i>0| for kmsan_context_state[i]. */
DEFINE_PER_CPU(int, kmsan_context_level);
DEFINE_PER_CPU(int, kmsan_in_interrupt);
DEFINE_PER_CPU(bool, kmsan_in_softirq);
DEFINE_PER_CPU(bool, kmsan_in_nmi);
DEFINE_PER_CPU(int, kmsan_in_runtime);
DEFINE_PER_CPU(unsigned long, kmsan_runtime_last_caller); // TODO(glider): debug-only
DEFINE_PER_CPU(char[CPU_ENTRY_AREA_SIZE], cpu_entry_area_shadow);
DEFINE_PER_CPU(char[CPU_ENTRY_AREA_SIZE], cpu_entry_area_origin);
extern int oops_in_progress;
kmsan_context_state *task_kmsan_context_state(void)
{
int cpu = smp_processor_id();
int level = this_cpu_read(kmsan_context_level);
kmsan_context_state *ret;
if (!kmsan_ready || IN_RUNTIME()) {
ret = &per_cpu(kmsan_percpu_cstate[0], cpu);
__memset(ret, 0, sizeof(kmsan_context_state));
return ret;
}
if (!level)
ret = ¤t->kmsan.cstate;
else
ret = &per_cpu(kmsan_percpu_cstate[level], cpu);
return ret;
}
/* For KMSAN_ENABLE and KMSAN_DISABLE */
void kmsan_enter_runtime(unsigned long *flags)
{
ENTER_RUNTIME(*flags);
}
EXPORT_SYMBOL(kmsan_enter_runtime);
void kmsan_leave_runtime(unsigned long *flags)
{
LEAVE_RUNTIME(*flags);
}
EXPORT_SYMBOL(kmsan_leave_runtime);
void inline do_kmsan_task_create(struct task_struct *task)
{
kmsan_task_state *state = &task->kmsan;
__memset(state, 0, sizeof(kmsan_task_state));
state->enabled = true;
state->allow_reporting = true;
state->is_reporting = false;
}
inline void kmsan_internal_memset_shadow(u64 address, int b, size_t size, bool checked)
{
void *shadow_start;
u64 page_offset;
size_t to_fill;
while (size) {
page_offset = address % PAGE_SIZE;
to_fill = min(PAGE_SIZE - page_offset, size);
shadow_start = kmsan_get_metadata_or_null(address, to_fill, /*is_origin*/false);
if (!shadow_start) {
if (checked) {
current->kmsan.is_reporting = true;
kmsan_pr_err("WARNING: not memsetting %d bytes starting at %px, because the shadow is NULL\n", to_fill, address);
current->kmsan.is_reporting = false;
BUG();
}
/* Otherwise just move on. */
} else {
__memset(shadow_start, b, to_fill);
}
address += to_fill;
size -= to_fill;
}
}
void kmsan_internal_poison_shadow(const volatile void *address, size_t size,
gfp_t flags, bool checked)
{
depot_stack_handle_t handle;
kmsan_internal_memset_shadow((u64)address, -1, size, checked);
handle = kmsan_save_stack_with_flags(flags);
kmsan_set_origin((u64)address, size, handle, checked);
}
void kmsan_internal_unpoison_shadow(const volatile void *address, size_t size, bool checked)
{
kmsan_internal_memset_shadow((u64)address, 0, size, checked);
kmsan_set_origin((u64)address, size, 0, checked);
}
static inline int in_irqentry_text(unsigned long ptr)
{
return (ptr >= (unsigned long)&__irqentry_text_start &&
ptr < (unsigned long)&__irqentry_text_end) ||
(ptr >= (unsigned long)&__softirqentry_text_start &&
ptr < (unsigned long)&__softirqentry_text_end);
}
static inline void filter_irq_stacks(struct stack_trace *trace)
{
int i;
if (!trace->nr_entries)
return;
for (i = 0; i < trace->nr_entries; i++)
if (in_irqentry_text(trace->entries[i])) {
/* Include the irqentry function into the stack. */
trace->nr_entries = i + 1;
break;
}
}
/* static */
inline depot_stack_handle_t kmsan_save_stack_with_flags(gfp_t flags)
{
depot_stack_handle_t handle;
unsigned long entries[KMSAN_STACK_DEPTH];
struct stack_trace trace = {
.nr_entries = 0,
.entries = entries,
.max_entries = KMSAN_STACK_DEPTH,
.skip = 0
};
kmsan_internal_unpoison_shadow(&trace, sizeof(trace), /*checked*/false);
save_stack_trace(&trace);
filter_irq_stacks(&trace);
if (trace.nr_entries != 0 &&
trace.entries[trace.nr_entries-1] == ULONG_MAX)
trace.nr_entries--;
/* Don't sleep (see might_sleep_if() in __alloc_pages_nodemask()). */
flags &= ~__GFP_DIRECT_RECLAIM;
handle = depot_save_stack(&trace, flags);
return handle;
}
inline depot_stack_handle_t kmsan_save_stack()
{
return kmsan_save_stack_with_flags(GFP_ATOMIC);
}
/*
* As with the regular memmove, do the following:
* - if src and dst don't overlap, use memcpy;
* - if src and dst overlap:
* - if src > dst, use memcpy;
* - if src < dst, use reverse-memcpy.
* Why this is correct:
* - problems may arise if for some part of the overlapping region we
* overwrite its shadow with a new value before copying it somewhere.
* But there's a 1:1 mapping between the kernel memory and its shadow,
* therefore if this doesn't happen with the kernel memory it can't happen
* with the shadow.
*/
inline
void kmsan_memcpy_memmove_metadata(u64 dst, u64 src, size_t n, bool is_memmove)
{
void *shadow_src, *shadow_dst;
depot_stack_handle_t *origin_src, *origin_dst, *align_shadow_src;
depot_stack_handle_t prev_origin, chained_origin, new_origin;
int i, iter, step, src_slots, dst_slots;
int rem_src, rem_dst, to_copy;
u64 cur_dst, cur_src;
u32 shadow;
if (is_memmove && (src > dst)) {
kmsan_memcpy_memmove_metadata(dst, src, n, /*is_memmove*/false);
return;
}
if (!n || dst == src)
return;
BUG_ON(dst + n < dst);
BUG_ON(src + n < src);
while (n) {
rem_src = PAGE_SIZE - (src % PAGE_SIZE);
rem_dst = PAGE_SIZE - (dst % PAGE_SIZE);
to_copy = min(n, min(rem_src, rem_dst));
cur_dst = dst;
cur_src = src;
src += to_copy;
dst += to_copy;
n -= to_copy;
shadow_dst = kmsan_get_metadata_or_null(cur_dst, to_copy, /*is_origin*/false);
if (!shadow_dst)
continue;
shadow_src = kmsan_get_metadata_or_null(cur_src, to_copy, /*is_origin*/false);
if (!shadow_src) {
/* |src| is untracked: zero out destination shadow, ignore the origins. */
__memset(shadow_dst, 0, to_copy);
continue;
}
origin_dst = kmsan_get_metadata_or_null(cur_dst, to_copy, /*is_origin*/true);
origin_src = kmsan_get_metadata_or_null(cur_src, to_copy, /*is_origin*/true);
BUG_ON(!origin_dst || !origin_src);
src_slots = (ALIGN(cur_src + to_copy, ORIGIN_SIZE) - ALIGN_DOWN(cur_src, ORIGIN_SIZE)) / ORIGIN_SIZE;
dst_slots = (ALIGN(cur_dst + to_copy, ORIGIN_SIZE) - ALIGN_DOWN(cur_dst, ORIGIN_SIZE)) / ORIGIN_SIZE;
BUG_ON((src_slots < 1) || (dst_slots < 1));
BUG_ON((src_slots - dst_slots > 1) || (dst_slots - src_slots < -1));
if (is_memmove)
__memmove(shadow_dst, shadow_src, to_copy);
else
__memcpy(shadow_dst, shadow_src, to_copy);
i = is_memmove ? min(src_slots, dst_slots) - 1 : 0;
iter = is_memmove ? -1 : 1;
align_shadow_src = ALIGN_DOWN((u64)shadow_src, ORIGIN_SIZE);
for (step = 0; step < min(src_slots, dst_slots); step++,i+=iter) {
shadow = align_shadow_src[i];
if (i == 0)
/*
* If |src| isn't aligned on ORIGIN_SIZE, don't
* look at the first |src % ORIGIN_SIZE| bytes
* of the first shadow slot.
*/
shadow = (shadow << (src % ORIGIN_SIZE)) >> (src % ORIGIN_SIZE);
if (i == src_slots - 1)
/*
* If |src + to_copy| isn't aligned on
* ORIGIN_SIZE, don't look at the last
* |(src + to_copy) % ORIGIN_SIZE| bytes of the
* last shadow slot.
*/
shadow = (shadow >> ((src + to_copy) % ORIGIN_SIZE)) >> ((src + to_copy) % ORIGIN_SIZE);
/*
* Overwrite the origin only if the corresponding
* shadow is nonempty.
*/
if (origin_src[i] && (origin_src[i] != prev_origin) && shadow) {
prev_origin = origin_src[i];
chained_origin = kmsan_internal_chain_origin(prev_origin);
/*
* kmsan_internal_chain_origin() may return
* NULL, but we don't want to lose the previous
* origin value.
*/
if (chained_origin)
new_origin = chained_origin;
else
new_origin = prev_origin;
}
if (shadow)
origin_dst[i] = new_origin;
else
origin_dst[i] = 0;
}
}
}
void kmsan_memcpy_metadata(u64 dst, u64 src, size_t n)
{
kmsan_memcpy_memmove_metadata(dst, src, n, /*is_memmove*/false);
}
void kmsan_memmove_metadata(u64 dst, u64 src, size_t n)
{
kmsan_memcpy_memmove_metadata(dst, src, n, /*is_memmove*/true);
}
static inline void kmsan_print_origin(depot_stack_handle_t origin)
{
struct stack_trace trace, chained_trace;
char *descr = NULL;
void *pc1 = NULL, *pc2 = NULL;
depot_stack_handle_t head;
if (!origin) {
kmsan_pr_err("Origin not found, presumably a false report.\n");
return;
}
while (true) {
depot_fetch_stack(origin, &trace);
if ((trace.nr_entries == 4) &&
((trace.entries[0] & KMSAN_MAGIC_MASK) == KMSAN_ALLOCA_MAGIC_ORIGIN)) {
descr = (char*)trace.entries[1];
pc1 = (void*)trace.entries[2];
pc2 = (void*)trace.entries[3];
kmsan_pr_err("Local variable description: %s\n", descr);
kmsan_pr_err("Variable was created at:\n");
kmsan_pr_err(" %pS\n", pc1);
kmsan_pr_err(" %pS\n", pc2);
break;
}
if (trace.nr_entries == 3) {
if ((trace.entries[0] & KMSAN_MAGIC_MASK) == KMSAN_CHAIN_MAGIC_ORIGIN_FULL) {
head = trace.entries[1];
origin = trace.entries[2];
kmsan_pr_err("Uninit was stored to memory at:\n");
depot_fetch_stack(head, &chained_trace);
print_stack_trace(&chained_trace, 0);
kmsan_pr_err("\n");
continue;
}
}
kmsan_pr_err("Uninit was created at:\n");
if (trace.entries)
print_stack_trace(&trace, 0);
else
kmsan_pr_err("No stack\n");
break;
}
}
depot_stack_handle_t inline kmsan_internal_chain_origin(depot_stack_handle_t id)
{
depot_stack_handle_t handle;
unsigned long entries[3];
struct stack_trace trace = {
.nr_entries = 3,
.entries = entries,
.max_entries = 3,
.skip = 0
};
u64 magic = KMSAN_CHAIN_MAGIC_ORIGIN_FULL;
struct stack_trace old_trace;
int depth = 0;
u64 old_magic;
static int skipped = 0;
if (!kmsan_ready)
return 0;
/*
* TODO(glider): invalid id may denote we've hit the stack depot
* capacity. We can either return the same id or generate a new one.
*/
if (!id) return id;
/*
* TODO(glider): this is slower, but will save us a lot of memory.
* Let us store the chain length in the lowest byte of the magic.
* Maybe we can cache the ids somehow to avoid fetching them?
*/
depot_fetch_stack(id, &old_trace);
if (!old_trace.nr_entries)
return id;
old_magic = old_trace.entries[0];
if ((old_magic & KMSAN_MAGIC_MASK) == KMSAN_CHAIN_MAGIC_ORIGIN_FULL) {
depth = old_magic & 0xff;
}
if (depth >= MAX_CHAIN_DEPTH) {
skipped++;
if (skipped % 10000 == 0) {
kmsan_pr_err("not chained %d origins\n", skipped);
dump_stack();
kmsan_print_origin(id);
}
return id;
}
depth++;
/* TODO(glider): how do we figure out we've dropped some frames? */
entries[0] = magic + depth;
entries[1] = kmsan_save_stack();
entries[2] = id;
handle = depot_save_stack(&trace, GFP_ATOMIC);
return handle;
}
inline
void kmsan_write_aligned_origin(const void *var, size_t size, u32 origin)
{
u32 *var_cast = (u32 *)var;
int i;
BUG_ON((u64)var_cast % ORIGIN_SIZE);
BUG_ON(size % ORIGIN_SIZE);
for (i = 0; i < size / ORIGIN_SIZE; i++)
var_cast[i] = origin;
}
/*
* TODO(glider): writing an initialized byte shouldn't zero out the origin, if
* the remaining three bytes are uninitialized.
*/
void kmsan_set_origin(u64 address, int size, u32 origin, bool checked)
{
void *origin_start;
u64 page_offset;
size_t to_fill, pad = 0;
if (!IS_ALIGNED(address, ORIGIN_SIZE)) {
pad = address % ORIGIN_SIZE;
address -= pad;
size += pad;
}
while (size > 0) {
page_offset = address % PAGE_SIZE;
to_fill = min(PAGE_SIZE - page_offset, size);
to_fill = ALIGN(to_fill, ORIGIN_SIZE);
BUG_ON(!to_fill);
origin_start = kmsan_get_metadata_or_null(address, to_fill, /*origin*/true);
if (!origin_start) {
if (checked) {
current->kmsan.is_reporting = true;
kmsan_pr_err("WARNING: not setting origing for %d bytes starting at %px, because the origin is NULL\n", to_fill, address);
current->kmsan.is_reporting = false;
BUG();
}
} else {
kmsan_write_aligned_origin(origin_start, to_fill, origin);
}
address += to_fill;
size -= to_fill;
}
}
static bool is_module_addr(const void *vaddr)
{
return (vaddr >= MODULES_VADDR) && (vaddr < MODULES_END);
}
void *get_cea_shadow_or_null(const void *addr)
{
int cpu = smp_processor_id();
int off;
if (!is_cpu_entry_area_addr(addr))
return NULL;
off = (char*)addr - (char*)get_cpu_entry_area(cpu);
if ((off < 0) || (off >= CPU_ENTRY_AREA_SIZE))
return NULL;
return &per_cpu(cpu_entry_area_shadow[off], cpu);
}
void *get_cea_origin_or_null(const void *addr)
{
int cpu = smp_processor_id();
int off;
if (!is_cpu_entry_area_addr(addr))
return NULL;
off = (char*)addr - (char*)get_cpu_entry_area(cpu);
if ((off < 0) || (off >= CPU_ENTRY_AREA_SIZE))
return NULL;
return &per_cpu(cpu_entry_area_origin[off], cpu);
}
struct page *vmalloc_to_page_or_null(const void *vaddr)
{
struct page *page;
if (!is_vmalloc_addr(vaddr) && !is_module_addr(vaddr))
return NULL;
page = vmalloc_to_page(vaddr);
if (pfn_valid(page_to_pfn(page)))
return page;
else
return NULL;
}
struct page *virt_to_page_or_null(const void *vaddr)
{
if (my_virt_addr_valid(vaddr))
return virt_to_page(vaddr);
else
return NULL;
}
/* TODO(glider): unite with kmsan_alloc_page()? */
void kmsan_prep_pages(struct page *page, unsigned int order)
{
int i;
for (i = 0; i < 1 << order; i++) {
page->shadow = 0;
page->origin = 0;
}
}
EXPORT_SYMBOL(kmsan_prep_pages);
int order_from_size(unsigned long size)
{
unsigned long pages = size >> PAGE_SHIFT;
if (!pages)
pages = 1;
if (hweight64(pages) > 1)
/*
* TODO(glider): round up to the next power of 2.
* This is a bit excessive.
*/
return fls(pages);
else
return fls(pages) - 1;
}
DEFINE_SPINLOCK(report_lock);
/*
* TODO(glider): |deep| is a dirty hack to skip an additional frame when
* calling kmsan_report() from kmsan_copy_to_user().
*/
inline void kmsan_report(void *caller, depot_stack_handle_t origin,
u64 address, int size, int off_first, int off_last, u64 user_addr, bool deep, int reason)
{
unsigned long flags;
struct stack_trace trace;
if (!kmsan_ready)
return;
if (!current->kmsan.allow_reporting)
return;
if (is_console_locked() || is_logbuf_locked())
return;
/* TODO(glider): temporarily disabling reports without origins. */
if (!origin)
return;
depot_fetch_stack(origin, &trace);
/* TODO(glider) */
current->kmsan.allow_reporting = false;
current->kmsan.is_reporting = true;
spin_lock_irqsave(&report_lock, flags);
kmsan_pr_err("==================================================================\n");
/* TODO(glider): inline this properly */
switch (reason) {
case REASON_ANY:
kmsan_pr_err("BUG: KMSAN: uninit-value in %pS\n", deep ? kmsan_internal_return_address(2) : kmsan_internal_return_address(1));
break;
case REASON_COPY_TO_USER:
kmsan_pr_err("BUG: KMSAN: kernel-infoleak in %pS\n", deep ? kmsan_internal_return_address(2) : kmsan_internal_return_address(1));
break;
}
dump_stack();
kmsan_pr_err("\n");
kmsan_print_origin(origin);
if (size) {
kmsan_pr_err("\n");
if (off_first == off_last)
kmsan_pr_err("Byte %d of %d is uninitialized\n", off_first, size);
else
kmsan_pr_err("Bytes %d-%d of %d are uninitialized\n", off_first, off_last, size);
}
if (address)
kmsan_pr_err("Memory access of size %d starts at %px\n", size, address);
if (user_addr && reason == REASON_COPY_TO_USER)
kmsan_pr_err("Data copied to user address %px\n", user_addr);
kmsan_pr_err("==================================================================\n");
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
spin_unlock_irqrestore(&report_lock, flags);
if (panic_on_warn)
panic("panic_on_warn set ...\n");
current->kmsan.is_reporting = false;
current->kmsan.allow_reporting = true;
}
void kmsan_internal_check_memory(const volatile void *addr, size_t size, const void *user_addr, int reason)
{
unsigned long irq_flags;
u64 addr64 = (u64)addr;
unsigned char *shadow = NULL;
depot_stack_handle_t *origin = NULL;
depot_stack_handle_t cur_origin = 0, new_origin = 0;
int cur_off_start = -1;
int i, chunk_size, pos;
pos = 0;
while (pos < size) {
chunk_size = min(size - pos, PAGE_SIZE - ((addr64 + pos) % PAGE_SIZE));
shadow = kmsan_get_metadata_or_null(addr64 + pos, chunk_size, /*is_origin*/false);
if (!shadow) {
/*
* This page is untracked. TODO(glider): assert.
* If there were uninitialized bytes before, report them.
*/
if (cur_origin) {
ENTER_RUNTIME(irq_flags);
kmsan_report(_THIS_IP_, cur_origin, addr, size, cur_off_start, pos - 1, user_addr, /*deep*/true, reason);
LEAVE_RUNTIME(irq_flags);
}
cur_origin = 0;
cur_off_start = -1;
pos += chunk_size;
continue;
}
for (i = 0; i < chunk_size; i++) {
if (!shadow[i]) {
/*
* This byte is unpoisoned. If there were
* poisoned bytes before, report them.
*/
if (cur_origin) {
ENTER_RUNTIME(irq_flags);
kmsan_report(_THIS_IP_, cur_origin, addr, size, cur_off_start, pos + i - 1, user_addr, /*deep*/true, reason);
LEAVE_RUNTIME(irq_flags);
}
cur_origin = 0;
cur_off_start = -1;
continue;
}
origin = kmsan_get_metadata_or_null(addr64 + pos + i, chunk_size - i, /*is_origin*/true);
BUG_ON(!origin);
new_origin = *origin;
/*
* Encountered new origin - report the previous
* uninitialized range.
*/
if (cur_origin != new_origin) {
if (cur_origin) {
ENTER_RUNTIME(irq_flags);
kmsan_report(_THIS_IP_, cur_origin, addr, size, cur_off_start, pos + i - 1, user_addr, /*deep*/true, reason);
LEAVE_RUNTIME(irq_flags);
}
cur_origin = new_origin;
cur_off_start = pos + i;
}
}
pos += chunk_size;
}
BUG_ON(pos != size);
if (cur_origin) {
ENTER_RUNTIME(irq_flags);
kmsan_report(_THIS_IP_, cur_origin, addr, size, cur_off_start, pos - 1, user_addr, /*deep*/true, reason);
LEAVE_RUNTIME(irq_flags);
}
}
void kmsan_check_memory(const volatile void *addr, size_t size)
{
return kmsan_internal_check_memory(addr, size, /*user_addr*/ 0, REASON_ANY);
}
EXPORT_SYMBOL(kmsan_check_memory);
/*
* TODO(glider): this check shouldn't be performed for origin pages, because
* they're always accessed after the shadow pages.
*/
bool metadata_is_contiguous(u64 addr, size_t size, bool is_origin) {
u64 cur_addr, next_addr, cur_meta_addr, next_meta_addr;
struct page *cur_page, *next_page;
depot_stack_handle_t *origin_p;
for (cur_addr = addr; next_addr < addr + size;
cur_addr = next_addr, next_addr += PAGE_SIZE) {
next_addr = cur_addr + PAGE_SIZE;
cur_page = virt_to_page_or_null(cur_addr);
next_page = virt_to_page_or_null(next_addr);
cur_meta_addr = page_address(is_origin ? cur_page->shadow : cur_page->origin);
next_meta_addr = page_address(is_origin ? next_page->shadow : next_page->origin);
if (cur_meta_addr != next_meta_addr - PAGE_SIZE) {
if ((addr < _sdata) || (addr >= _edata)) {
const char *fname = is_origin ? "shadow" : "origin";
/*
* Skip reports on __data.
* TODO(glider): allocate contiguous shadow for __data instead.
*/
current->kmsan.is_reporting = true;
kmsan_pr_err("BUG: attempting to access two shadow page ranges.\n");
dump_stack();
kmsan_pr_err("\n");
kmsan_pr_err("Access of size %d at %px.\n", size, addr);
kmsan_pr_err("Addresses belonging to different ranges are: %px and %px\n", cur_addr, next_addr);
kmsan_pr_err("page[0].%s: %px, page[1].%s: %px\n", fname, cur_meta_addr, fname, next_meta_addr);
origin_p = kmsan_get_metadata_or_null(addr, 1, /*is_origin*/true);
if (origin_p) {
kmsan_pr_err("Origin: %px\n", *origin_p);
kmsan_print_origin(*origin_p);
} else {
kmsan_pr_err("Origin: unavailable\n");
}
current->kmsan.is_reporting = false;
return false;
}
}
}
return true;
}
/*
* TODO(glider): all other shadow getters are broken, so let's write another
* one. The semantic is pretty straightforward: either return a valid shadow
* pointer or NULL. The caller must BUG_ON on NULL if he wants to.
* The return value of this function should not depend on whether we're in the
* runtime or not.
*/
__always_inline
void *kmsan_get_metadata_or_null(u64 addr, size_t size, bool is_origin)
{
struct page *page;
void *ret;
u64 pad, offset;
if (is_origin && !IS_ALIGNED(addr, ORIGIN_SIZE)) {
pad = addr % ORIGIN_SIZE;
addr -= pad;
size += pad;
}
if (!my_virt_addr_valid(addr)) {
page = vmalloc_to_page_or_null(addr);
if (page)
goto next;
ret = is_origin ? get_cea_origin_or_null(addr) : get_cea_shadow_or_null(addr);
if (ret)
return ret;
}
page = virt_to_page_or_null(addr);
if (!page)
return NULL;
next:
if (!page->shadow || !page->origin)
return NULL;
offset = addr % PAGE_SIZE;
if (offset + size - 1 > PAGE_SIZE) {
/*
* The access overflows the current page and touches the
* subsequent ones. Make sure the shadow/origin pages are also
* consequent.
*/
if (!metadata_is_contiguous(addr, size, is_origin))
return NULL;
}
ret = page_address(is_origin ? page->origin : page->shadow) + offset;
return ret;
}
noinline
shadow_origin_ptr_t kmsan_get_shadow_origin_ptr(u64 addr, u64 size, bool store)
{
shadow_origin_ptr_t ret;
struct page *page;
u64 pad, offset, o_offset;
u64 o_addr = addr;
void *shadow, *origin;
if (size > PAGE_SIZE) {
WARN(1, "size too big in kmsan_get_shadow_origin_ptr(%px, %d, %d)\n", addr, size, store);
BUG();
}
if (store) {
ret.s = dummy_store_page;
ret.o = dummy_store_page;
} else {
ret.s = dummy_load_page;
ret.o = dummy_load_page;
}
if (!kmsan_ready || IN_RUNTIME())
return ret;
if (!IS_ALIGNED(addr, ORIGIN_SIZE)) {
pad = addr % ORIGIN_SIZE;
o_addr -= pad;
}
if (!my_virt_addr_valid(addr)) {
page = vmalloc_to_page_or_null(addr);
if (page)
goto next;
if (shadow = get_cea_shadow_or_null(addr)) {
ret.s = shadow;
ret.o = get_cea_origin_or_null(o_addr);
return ret;
}
}
page = virt_to_page_or_null(addr);
if (!page)
return ret;
next:
if (!page->shadow || !page->origin)
return ret;
offset = addr % PAGE_SIZE;
o_offset = o_addr % PAGE_SIZE;
if (offset + size - 1 > PAGE_SIZE) {
/*
* The access overflows the current page and touches the
* subsequent ones. Make sure the shadow/origin pages are also
* consequent.
*/
if (!metadata_is_contiguous(addr, size, /*is_origin*/false))
return ret;
}
shadow = page_address(page->shadow) + offset;
ret.s = shadow;
origin = page_address(page->origin) + o_offset;
ret.o = origin;
return ret;
}