On Thu, Jan 16, 2020 at 2:24 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > 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. > > Suggested-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > Link: https://lore.kernel.org/lkml/CACT4Y+bsLJ-wFx_TaXqax3JByUOWB3uk787LsyMVcfW6JzzGvg@xxxxxxxxxxxxxx > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > lib/ubsan.c | 36 +++++++++++++++--------------------- > 1 file changed, 15 insertions(+), 21 deletions(-) > > diff --git a/lib/ubsan.c b/lib/ubsan.c > index 429663eef6a7..057d5375bfc6 100644 > --- a/lib/ubsan.c > +++ b/lib/ubsan.c > @@ -45,13 +45,6 @@ static bool was_reported(struct source_location *location) > 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, size_t size, struct type_descriptor *type, > } > } > > -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 overflow_data *data, void *lhs, > 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(struct overflow_data *data, > 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(struct overflow_data *data, > 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 type_mismatch_data_common *data) > if (suppress_report(data->location)) > return; > > - ubsan_prologue(data->location); > + ubsan_prologue(data->location, "NULL pointer dereference"); Not crucially important, but I think it makes sense to use the single-word-with-hyphens bug type format like in KASAN here, e.g. null-ptr-deref, misaligned-access, etc. > > 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(struct type_mismatch_data_common *data, > 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(struct type_mismatch_data_common *data, > 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 out_of_bounds_data *data, void *index) > 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(struct shift_out_of_bounds_data *data, > 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_of_bounds); > > 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(struct invalid_value_data *data, > 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); > > -- > 2.20.1 > > -- > You received this message because you are subscribed to the Google Groups "syzkaller" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller/20200116012321.26254-7-keescook%40chromium.org.
