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    Subject[PATCH v2 11/37] kasan: decode stack frame only with KASAN_STACK_ENABLE
    From
    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: Andrey Konovalov <andreyknvl@google.com>
    Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
    ---
    Change-Id: I084e3214f2b40dc0bef7c5a9fafdc6f5c42b06a2
    ---
    mm/kasan/kasan.h | 6 ++
    mm/kasan/report.c | 162 --------------------------------------
    mm/kasan/report_generic.c | 161 +++++++++++++++++++++++++++++++++++++
    3 files changed, 167 insertions(+), 162 deletions(-)

    diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
    index cf6a135860f2..15cf3e0018ae 100644
    --- a/mm/kasan/kasan.h
    +++ b/mm/kasan/kasan.h
    @@ -168,6 +168,12 @@ 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);

    +#ifdef CONFIG_KASAN_STACK_ENABLE
    +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);
    diff --git a/mm/kasan/report.c b/mm/kasan/report.c
    index f16591ba9e2e..ddaf9d14ca81 100644
    --- a/mm/kasan/report.c
    +++ b/mm/kasan/report.c
    @@ -214,168 +214,6 @@ 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);
    diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c
    index 4dce1633b082..427f4ac80cca 100644
    --- a/mm/kasan/report_generic.c
    +++ b/mm/kasan/report_generic.c
    @@ -127,6 +127,167 @@ const char *get_bug_type(struct kasan_access_info *info)
    return get_wild_bug_type(info);
    }

    +#ifdef CONFIG_KASAN_STACK_ENABLE
    +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_ENABLE */
    +
    #define DEFINE_ASAN_REPORT_LOAD(size) \
    void __asan_report_load##size##_noabort(unsigned long addr) \
    { \
    --
    2.28.0.618.gf4bc123cb7-goog
    \
     
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      Last update: 2020-09-15 23:33    [W:2.358 / U:0.036 seconds]
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