Commit 11c7d634 authored by Andrey Konovalov's avatar Andrey Konovalov
Browse files

kasan: decode stack frame only with KASAN_STACK_ENABLE



Decoding routines aren't needed when CONFIG_KASAN_STACK_ENABLE is not
enabled. Currently only generic KASAN mode implements stack error
reporting.

No functional changes for software modes.

Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino's avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
---
Change-Id: I084e3214f2b40dc0bef7c5a9fafdc6f5c42b06a2
parent dc28c110
......@@ -169,6 +169,12 @@ bool check_invalid_free(void *addr);
void *find_first_bad_addr(void *addr, size_t size);
const char *get_bug_type(struct kasan_access_info *info);
#if defined(CONFIG_KASAN_GENERIC) && CONFIG_KASAN_STACK
void print_address_stack_frame(const void *addr);
#else
static inline void print_address_stack_frame(const void *addr) { }
#endif
bool kasan_report(unsigned long addr, size_t size,
bool is_write, unsigned long ip);
void kasan_report_invalid_free(void *object, unsigned long ip);
......
......@@ -211,168 +211,6 @@ static inline bool init_task_stack_addr(const void *addr)
sizeof(init_thread_union.stack));
}
static bool __must_check tokenize_frame_descr(const char **frame_descr,
char *token, size_t max_tok_len,
unsigned long *value)
{
const char *sep = strchr(*frame_descr, ' ');
if (sep == NULL)
sep = *frame_descr + strlen(*frame_descr);
if (token != NULL) {
const size_t tok_len = sep - *frame_descr;
if (tok_len + 1 > max_tok_len) {
pr_err("KASAN internal error: frame description too long: %s\n",
*frame_descr);
return false;
}
/* Copy token (+ 1 byte for '\0'). */
strlcpy(token, *frame_descr, tok_len + 1);
}
/* Advance frame_descr past separator. */
*frame_descr = sep + 1;
if (value != NULL && kstrtoul(token, 10, value)) {
pr_err("KASAN internal error: not a valid number: %s\n", token);
return false;
}
return true;
}
static void print_decoded_frame_descr(const char *frame_descr)
{
/*
* We need to parse the following string:
* "n alloc_1 alloc_2 ... alloc_n"
* where alloc_i looks like
* "offset size len name"
* or "offset size len name:line".
*/
char token[64];
unsigned long num_objects;
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
&num_objects))
return;
pr_err("\n");
pr_err("this frame has %lu %s:\n", num_objects,
num_objects == 1 ? "object" : "objects");
while (num_objects--) {
unsigned long offset;
unsigned long size;
/* access offset */
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
&offset))
return;
/* access size */
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
&size))
return;
/* name length (unused) */
if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL))
return;
/* object name */
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
NULL))
return;
/* Strip line number; without filename it's not very helpful. */
strreplace(token, ':', '\0');
/* Finally, print object information. */
pr_err(" [%lu, %lu) '%s'", offset, offset + size, token);
}
}
static bool __must_check get_address_stack_frame_info(const void *addr,
unsigned long *offset,
const char **frame_descr,
const void **frame_pc)
{
unsigned long aligned_addr;
unsigned long mem_ptr;
const u8 *shadow_bottom;
const u8 *shadow_ptr;
const unsigned long *frame;
BUILD_BUG_ON(IS_ENABLED(CONFIG_STACK_GROWSUP));
/*
* NOTE: We currently only support printing frame information for
* accesses to the task's own stack.
*/
if (!object_is_on_stack(addr))
return false;
aligned_addr = round_down((unsigned long)addr, sizeof(long));
mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE);
shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr);
shadow_bottom = kasan_mem_to_shadow(end_of_stack(current));
while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) {
shadow_ptr--;
mem_ptr -= KASAN_GRANULE_SIZE;
}
while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) {
shadow_ptr--;
mem_ptr -= KASAN_GRANULE_SIZE;
}
if (shadow_ptr < shadow_bottom)
return false;
frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE);
if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) {
pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n",
frame[0]);
return false;
}
*offset = (unsigned long)addr - (unsigned long)frame;
*frame_descr = (const char *)frame[1];
*frame_pc = (void *)frame[2];
return true;
}
static void print_address_stack_frame(const void *addr)
{
unsigned long offset;
const char *frame_descr;
const void *frame_pc;
if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
return;
if (!get_address_stack_frame_info(addr, &offset, &frame_descr,
&frame_pc))
return;
/*
* get_address_stack_frame_info only returns true if the given addr is
* on the current task's stack.
*/
pr_err("\n");
pr_err("addr %px is located in stack of task %s/%d at offset %lu in frame:\n",
addr, current->comm, task_pid_nr(current), offset);
pr_err(" %pS\n", frame_pc);
if (!frame_descr)
return;
print_decoded_frame_descr(frame_descr);
}
static void print_address_description(void *addr, u8 tag)
{
struct page *page = kasan_addr_to_page(addr);
......
......@@ -16,6 +16,7 @@
#include <linux/mm.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/stackdepot.h>
#include <linux/stacktrace.h>
......@@ -122,6 +123,167 @@ const char *get_bug_type(struct kasan_access_info *info)
return get_wild_bug_type(info);
}
#if CONFIG_KASAN_STACK
static bool __must_check tokenize_frame_descr(const char **frame_descr,
char *token, size_t max_tok_len,
unsigned long *value)
{
const char *sep = strchr(*frame_descr, ' ');
if (sep == NULL)
sep = *frame_descr + strlen(*frame_descr);
if (token != NULL) {
const size_t tok_len = sep - *frame_descr;
if (tok_len + 1 > max_tok_len) {
pr_err("KASAN internal error: frame description too long: %s\n",
*frame_descr);
return false;
}
/* Copy token (+ 1 byte for '\0'). */
strlcpy(token, *frame_descr, tok_len + 1);
}
/* Advance frame_descr past separator. */
*frame_descr = sep + 1;
if (value != NULL && kstrtoul(token, 10, value)) {
pr_err("KASAN internal error: not a valid number: %s\n", token);
return false;
}
return true;
}
static void print_decoded_frame_descr(const char *frame_descr)
{
/*
* We need to parse the following string:
* "n alloc_1 alloc_2 ... alloc_n"
* where alloc_i looks like
* "offset size len name"
* or "offset size len name:line".
*/
char token[64];
unsigned long num_objects;
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
&num_objects))
return;
pr_err("\n");
pr_err("this frame has %lu %s:\n", num_objects,
num_objects == 1 ? "object" : "objects");
while (num_objects--) {
unsigned long offset;
unsigned long size;
/* access offset */
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
&offset))
return;
/* access size */
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
&size))
return;
/* name length (unused) */
if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL))
return;
/* object name */
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
NULL))
return;
/* Strip line number; without filename it's not very helpful. */
strreplace(token, ':', '\0');
/* Finally, print object information. */
pr_err(" [%lu, %lu) '%s'", offset, offset + size, token);
}
}
static bool __must_check get_address_stack_frame_info(const void *addr,
unsigned long *offset,
const char **frame_descr,
const void **frame_pc)
{
unsigned long aligned_addr;
unsigned long mem_ptr;
const u8 *shadow_bottom;
const u8 *shadow_ptr;
const unsigned long *frame;
BUILD_BUG_ON(IS_ENABLED(CONFIG_STACK_GROWSUP));
/*
* NOTE: We currently only support printing frame information for
* accesses to the task's own stack.
*/
if (!object_is_on_stack(addr))
return false;
aligned_addr = round_down((unsigned long)addr, sizeof(long));
mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE);
shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr);
shadow_bottom = kasan_mem_to_shadow(end_of_stack(current));
while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) {
shadow_ptr--;
mem_ptr -= KASAN_GRANULE_SIZE;
}
while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) {
shadow_ptr--;
mem_ptr -= KASAN_GRANULE_SIZE;
}
if (shadow_ptr < shadow_bottom)
return false;
frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE);
if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) {
pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n",
frame[0]);
return false;
}
*offset = (unsigned long)addr - (unsigned long)frame;
*frame_descr = (const char *)frame[1];
*frame_pc = (void *)frame[2];
return true;
}
void print_address_stack_frame(const void *addr)
{
unsigned long offset;
const char *frame_descr;
const void *frame_pc;
if (!get_address_stack_frame_info(addr, &offset, &frame_descr,
&frame_pc))
return;
/*
* get_address_stack_frame_info only returns true if the given addr is
* on the current task's stack.
*/
pr_err("\n");
pr_err("addr %px is located in stack of task %s/%d at offset %lu in frame:\n",
addr, current->comm, task_pid_nr(current), offset);
pr_err(" %pS\n", frame_pc);
if (!frame_descr)
return;
print_decoded_frame_descr(frame_descr);
}
#endif /* CONFIG_KASAN_STACK */
#define DEFINE_ASAN_REPORT_LOAD(size) \
void __asan_report_load##size##_noabort(unsigned long addr) \
{ \
......
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