[patch 163/166] ubsan: include bug type in report header

Andrew Morton
2020-04-07T03:12:49Z

From: Kees Cook <keescook@chromium.org>
Subject: ubsan: include bug type in report header

When syzbot tries to figure out how to deduplicate bug reports, it prefers
seeing a hint about a specific bug type (we can do better than just
"UBSAN"). This lifts the handler reason into the UBSAN report line that
includes the file path that tripped a check. Unfortunately, UBSAN does
not provide function names.

Link: http://lkml.kernel.org/r/20200227193516.32566-7-keescook@chromium.org
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://lore.kernel.org/lkml/CACT4Y+bsLJ-wFx_TaXqax3JByUOWB3uk787LsyMVcfW6JzzGvg@mail.gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

lib/ubsan.c | 36 +++++++++++++++---------------------
1 file changed, 15 insertions(+), 21 deletions(-)

--- a/lib/ubsan.c~ubsan-include-bug-type-in-report-header
+++ a/lib/ubsan.c
@@ -45,13 +45,6 @@ static bool was_reported(struct source_l
return test_and_set_bit(REPORTED_BIT, &location->reported);
}

-static void print_source_location(const char *prefix,
- struct source_location *loc)
-{
- pr_err("%s %s:%d:%d\n", prefix, loc->file_name,
- loc->line & LINE_MASK, loc->column & COLUMN_MASK);
-}
-
static bool suppress_report(struct source_location *loc)
{
return current->in_ubsan || was_reported(loc);
@@ -140,13 +133,14 @@ static void val_to_string(char *str, siz
}
}

-static void ubsan_prologue(struct source_location *location)
+static void ubsan_prologue(struct source_location *loc, const char *reason)
{
current->in_ubsan++;

pr_err("========================================"
"========================================\n");
- print_source_location("UBSAN: Undefined behaviour in", location);
+ pr_err("UBSAN: %s in %s:%d:%d\n", reason, loc->file_name,
+ loc->line & LINE_MASK, loc->column & COLUMN_MASK);
}

static void ubsan_epilogue(void)
@@ -180,12 +174,12 @@ static void handle_overflow(struct overf
if (suppress_report(&data->location))
return;

- ubsan_prologue(&data->location);
+ ubsan_prologue(&data->location, type_is_signed(type) ?
+ "signed-integer-overflow" :
+ "unsigned-integer-overflow");

val_to_string(lhs_val_str, sizeof(lhs_val_str), type, lhs);
val_to_string(rhs_val_str, sizeof(rhs_val_str), type, rhs);
- pr_err("%s integer overflow:\n",
- type_is_signed(type) ? "signed" : "unsigned");
pr_err("%s %c %s cannot be represented in type %s\n",
lhs_val_str,
op,
@@ -225,7 +219,7 @@ void __ubsan_handle_negate_overflow(stru
if (suppress_report(&data->location))
return;

- ubsan_prologue(&data->location);
+ ubsan_prologue(&data->location, "negation-overflow");

val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val);

@@ -245,7 +239,7 @@ void __ubsan_handle_divrem_overflow(stru
if (suppress_report(&data->location))
return;

- ubsan_prologue(&data->location);
+ ubsan_prologue(&data->location, "division-overflow");

val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs);

@@ -264,7 +258,7 @@ static void handle_null_ptr_deref(struct
if (suppress_report(data->location))
return;

- ubsan_prologue(data->location);
+ ubsan_prologue(data->location, "null-ptr-deref");

pr_err("%s null pointer of type %s\n",
type_check_kinds[data->type_check_kind],
@@ -279,7 +273,7 @@ static void handle_misaligned_access(str
if (suppress_report(data->location))
return;

- ubsan_prologue(data->location);
+ ubsan_prologue(data->location, "misaligned-access");

pr_err("%s misaligned address %p for type %s\n",
type_check_kinds[data->type_check_kind],
@@ -295,7 +289,7 @@ static void handle_object_size_mismatch(
if (suppress_report(data->location))
return;

- ubsan_prologue(data->location);
+ ubsan_prologue(data->location, "object-size-mismatch");
pr_err("%s address %p with insufficient space\n",
type_check_kinds[data->type_check_kind],
(void *) ptr);
@@ -354,7 +348,7 @@ void __ubsan_handle_out_of_bounds(struct
if (suppress_report(&data->location))
return;

- ubsan_prologue(&data->location);
+ ubsan_prologue(&data->location, "array-index-out-of-bounds");

val_to_string(index_str, sizeof(index_str), data->index_type, index);
pr_err("index %s is out of range for type %s\n", index_str,
@@ -375,7 +369,7 @@ void __ubsan_handle_shift_out_of_bounds(
if (suppress_report(&data->location))
goto out;

- ubsan_prologue(&data->location);
+ ubsan_prologue(&data->location, "shift-out-of-bounds");

val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs);
val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs);
@@ -407,7 +401,7 @@ EXPORT_SYMBOL(__ubsan_handle_shift_out_o

void __ubsan_handle_builtin_unreachable(struct unreachable_data *data)
{
- ubsan_prologue(&data->location);
+ ubsan_prologue(&data->location, "unreachable");
pr_err("calling __builtin_unreachable()\n");
ubsan_epilogue();
panic("can't return from __builtin_unreachable()");
@@ -422,7 +416,7 @@ void __ubsan_handle_load_invalid_value(s
if (suppress_report(&data->location))
return;

- ubsan_prologue(&data->location);
+ ubsan_prologue(&data->location, "invalid-load");

val_to_string(val_str, sizeof(val_str), data->type, val);

_