diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 2 | ||||
| -rw-r--r-- | lib/Kconfig.ubsan | 29 | ||||
| -rw-r--r-- | lib/Makefile | 3 | ||||
| -rw-r--r-- | lib/ubsan.c | 456 | ||||
| -rw-r--r-- | lib/ubsan.h | 84 |
5 files changed, 574 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index f75a33f29f6e..157220b9ff05 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1893,6 +1893,8 @@ source "samples/Kconfig" source "lib/Kconfig.kgdb" +source "lib/Kconfig.ubsan" + config ARCH_HAS_DEVMEM_IS_ALLOWED bool diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan new file mode 100644 index 000000000000..49518fb48cab --- /dev/null +++ b/lib/Kconfig.ubsan @@ -0,0 +1,29 @@ +config ARCH_HAS_UBSAN_SANITIZE_ALL + bool + +config UBSAN + bool "Undefined behaviour sanity checker" + help + This option enables undefined behaviour sanity checker + Compile-time instrumentation is used to detect various undefined + behaviours in runtime. Various types of checks may be enabled + via boot parameter ubsan_handle (see: Documentation/ubsan.txt). + +config UBSAN_SANITIZE_ALL + bool "Enable instrumentation for the entire kernel" + depends on UBSAN + depends on ARCH_HAS_UBSAN_SANITIZE_ALL + default y + help + This option activates instrumentation for the entire kernel. + If you don't enable this option, you have to explicitly specify + UBSAN_SANITIZE := y for the files/directories you want to check for UB. + +config UBSAN_ALIGNMENT + bool "Enable checking of pointers alignment" + depends on UBSAN + default y if !HAVE_EFFICIENT_UNALIGNED_ACCESS + help + This option enables detection of unaligned memory accesses. + Enabling this option on architectures that support unalligned + accesses may produce a lot of false positives. diff --git a/lib/Makefile b/lib/Makefile index b2a82e600987..2d4bc33d09b4 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -209,3 +209,6 @@ quiet_cmd_build_OID_registry = GEN $@ clean-files += oid_registry_data.c obj-$(CONFIG_UCS2_STRING) += ucs2_string.o +obj-$(CONFIG_UBSAN) += ubsan.o + +UBSAN_SANITIZE_ubsan.o := n diff --git a/lib/ubsan.c b/lib/ubsan.c new file mode 100644 index 000000000000..8799ae5e2e42 --- /dev/null +++ b/lib/ubsan.c @@ -0,0 +1,456 @@ +/* + * UBSAN error reporting functions + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <ryabinin.a.a@gmail.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/bitops.h> +#include <linux/bug.h> +#include <linux/ctype.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/sched.h> + +#include "ubsan.h" + +const char *type_check_kinds[] = { + "load of", + "store to", + "reference binding to", + "member access within", + "member call on", + "constructor call on", + "downcast of", + "downcast of" +}; + +#define REPORTED_BIT 31 + +#if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN) +#define COLUMN_MASK (~(1U << REPORTED_BIT)) +#define LINE_MASK (~0U) +#else +#define COLUMN_MASK (~0U) +#define LINE_MASK (~(1U << REPORTED_BIT)) +#endif + +#define VALUE_LENGTH 40 + +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); +} + +static bool type_is_int(struct type_descriptor *type) +{ + return type->type_kind == type_kind_int; +} + +static bool type_is_signed(struct type_descriptor *type) +{ + WARN_ON(!type_is_int(type)); + return type->type_info & 1; +} + +static unsigned type_bit_width(struct type_descriptor *type) +{ + return 1 << (type->type_info >> 1); +} + +static bool is_inline_int(struct type_descriptor *type) +{ + unsigned inline_bits = sizeof(unsigned long)*8; + unsigned bits = type_bit_width(type); + + WARN_ON(!type_is_int(type)); + + return bits <= inline_bits; +} + +static s_max get_signed_val(struct type_descriptor *type, unsigned long val) +{ + if (is_inline_int(type)) { + unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type); + return ((s_max)val) << extra_bits >> extra_bits; + } + + if (type_bit_width(type) == 64) + return *(s64 *)val; + + return *(s_max *)val; +} + +static bool val_is_negative(struct type_descriptor *type, unsigned long val) +{ + return type_is_signed(type) && get_signed_val(type, val) < 0; +} + +static u_max get_unsigned_val(struct type_descriptor *type, unsigned long val) +{ + if (is_inline_int(type)) + return val; + + if (type_bit_width(type) == 64) + return *(u64 *)val; + + return *(u_max *)val; +} + +static void val_to_string(char *str, size_t size, struct type_descriptor *type, + unsigned long value) +{ + if (type_is_int(type)) { + if (type_bit_width(type) == 128) { +#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) + u_max val = get_unsigned_val(type, value); + + scnprintf(str, size, "0x%08x%08x%08x%08x", + (u32)(val >> 96), + (u32)(val >> 64), + (u32)(val >> 32), + (u32)(val)); +#else + WARN_ON(1); +#endif + } else if (type_is_signed(type)) { + scnprintf(str, size, "%lld", + (s64)get_signed_val(type, value)); + } else { + scnprintf(str, size, "%llu", + (u64)get_unsigned_val(type, value)); + } + } +} + +static bool location_is_valid(struct source_location *loc) +{ + return loc->file_name != NULL; +} + +static DEFINE_SPINLOCK(report_lock); + +static void ubsan_prologue(struct source_location *location, + unsigned long *flags) +{ + current->in_ubsan++; + spin_lock_irqsave(&report_lock, *flags); + + pr_err("========================================" + "========================================\n"); + print_source_location("UBSAN: Undefined behaviour in", location); +} + +static void ubsan_epilogue(unsigned long *flags) +{ + dump_stack(); + pr_err("========================================" + "========================================\n"); + spin_unlock_irqrestore(&report_lock, *flags); + current->in_ubsan--; +} + +static void handle_overflow(struct overflow_data *data, unsigned long lhs, + unsigned long rhs, char op) +{ + + struct type_descriptor *type = data->type; + unsigned long flags; + char lhs_val_str[VALUE_LENGTH]; + char rhs_val_str[VALUE_LENGTH]; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + 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, + rhs_val_str, + type->type_name); + + ubsan_epilogue(&flags); +} + +void __ubsan_handle_add_overflow(struct overflow_data *data, + unsigned long lhs, + unsigned long rhs) +{ + + handle_overflow(data, lhs, rhs, '+'); +} +EXPORT_SYMBOL(__ubsan_handle_add_overflow); + +void __ubsan_handle_sub_overflow(struct overflow_data *data, + unsigned long lhs, + unsigned long rhs) +{ + handle_overflow(data, lhs, rhs, '-'); +} +EXPORT_SYMBOL(__ubsan_handle_sub_overflow); + +void __ubsan_handle_mul_overflow(struct overflow_data *data, + unsigned long lhs, + unsigned long rhs) +{ + handle_overflow(data, lhs, rhs, '*'); +} +EXPORT_SYMBOL(__ubsan_handle_mul_overflow); + +void __ubsan_handle_negate_overflow(struct overflow_data *data, + unsigned long old_val) +{ + unsigned long flags; + char old_val_str[VALUE_LENGTH]; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val); + + pr_err("negation of %s cannot be represented in type %s:\n", + old_val_str, data->type->type_name); + + ubsan_epilogue(&flags); +} +EXPORT_SYMBOL(__ubsan_handle_negate_overflow); + + +void __ubsan_handle_divrem_overflow(struct overflow_data *data, + unsigned long lhs, + unsigned long rhs) +{ + unsigned long flags; + char rhs_val_str[VALUE_LENGTH]; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs); + + if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1) + pr_err("division of %s by -1 cannot be represented in type %s\n", + rhs_val_str, data->type->type_name); + else + pr_err("division by zero\n"); + + ubsan_epilogue(&flags); +} +EXPORT_SYMBOL(__ubsan_handle_divrem_overflow); + +static void handle_null_ptr_deref(struct type_mismatch_data *data) +{ + unsigned long flags; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + pr_err("%s null pointer of type %s\n", + type_check_kinds[data->type_check_kind], + data->type->type_name); + + ubsan_epilogue(&flags); +} + +static void handle_missaligned_access(struct type_mismatch_data *data, + unsigned long ptr) +{ + unsigned long flags; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + pr_err("%s misaligned address %p for type %s\n", + type_check_kinds[data->type_check_kind], + (void *)ptr, data->type->type_name); + pr_err("which requires %ld byte alignment\n", data->alignment); + + ubsan_epilogue(&flags); +} + +static void handle_object_size_mismatch(struct type_mismatch_data *data, + unsigned long ptr) +{ + unsigned long flags; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + pr_err("%s address %pk with insufficient space\n", + type_check_kinds[data->type_check_kind], + (void *) ptr); + pr_err("for an object of type %s\n", data->type->type_name); + ubsan_epilogue(&flags); +} + +void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, + unsigned long ptr) +{ + + if (!ptr) + handle_null_ptr_deref(data); + else if (data->alignment && !IS_ALIGNED(ptr, data->alignment)) + handle_missaligned_access(data, ptr); + else + handle_object_size_mismatch(data, ptr); +} +EXPORT_SYMBOL(__ubsan_handle_type_mismatch); + +void __ubsan_handle_nonnull_return(struct nonnull_return_data *data) +{ + unsigned long flags; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + pr_err("null pointer returned from function declared to never return null\n"); + + if (location_is_valid(&data->attr_location)) + print_source_location("returns_nonnull attribute specified in", + &data->attr_location); + + ubsan_epilogue(&flags); +} +EXPORT_SYMBOL(__ubsan_handle_nonnull_return); + +void __ubsan_handle_vla_bound_not_positive(struct vla_bound_data *data, + unsigned long bound) +{ + unsigned long flags; + char bound_str[VALUE_LENGTH]; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + val_to_string(bound_str, sizeof(bound_str), data->type, bound); + pr_err("variable length array bound value %s <= 0\n", bound_str); + + ubsan_epilogue(&flags); +} +EXPORT_SYMBOL(__ubsan_handle_vla_bound_not_positive); + +void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data, + unsigned long index) +{ + unsigned long flags; + char index_str[VALUE_LENGTH]; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + 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, + data->array_type->type_name); + ubsan_epilogue(&flags); +} +EXPORT_SYMBOL(__ubsan_handle_out_of_bounds); + +void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data, + unsigned long lhs, unsigned long rhs) +{ + unsigned long flags; + struct type_descriptor *rhs_type = data->rhs_type; + struct type_descriptor *lhs_type = data->lhs_type; + char rhs_str[VALUE_LENGTH]; + char lhs_str[VALUE_LENGTH]; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs); + val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs); + + if (val_is_negative(rhs_type, rhs)) + pr_err("shift exponent %s is negative\n", rhs_str); + + else if (get_unsigned_val(rhs_type, rhs) >= + type_bit_width(lhs_type)) + pr_err("shift exponent %s is too large for %u-bit type %s\n", + rhs_str, + type_bit_width(lhs_type), + lhs_type->type_name); + else if (val_is_negative(lhs_type, lhs)) + pr_err("left shift of negative value %s\n", + lhs_str); + else + pr_err("left shift of %s by %s places cannot be" + " represented in type %s\n", + lhs_str, rhs_str, + lhs_type->type_name); + + ubsan_epilogue(&flags); +} +EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds); + + +void __noreturn +__ubsan_handle_builtin_unreachable(struct unreachable_data *data) +{ + unsigned long flags; + + ubsan_prologue(&data->location, &flags); + pr_err("calling __builtin_unreachable()\n"); + ubsan_epilogue(&flags); + panic("can't return from __builtin_unreachable()"); +} +EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable); + +void __ubsan_handle_load_invalid_value(struct invalid_value_data *data, + unsigned long val) +{ + unsigned long flags; + char val_str[VALUE_LENGTH]; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, &flags); + + val_to_string(val_str, sizeof(val_str), data->type, val); + + pr_err("load of value %s is not a valid value for type %s\n", + val_str, data->type->type_name); + + ubsan_epilogue(&flags); +} +EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); diff --git a/lib/ubsan.h b/lib/ubsan.h new file mode 100644 index 000000000000..b2d18d4a53f5 --- /dev/null +++ b/lib/ubsan.h @@ -0,0 +1,84 @@ +#ifndef _LIB_UBSAN_H +#define _LIB_UBSAN_H + +enum { + type_kind_int = 0, + type_kind_float = 1, + type_unknown = 0xffff +}; + +struct type_descriptor { + u16 type_kind; + u16 type_info; + char type_name[1]; +}; + +struct source_location { + const char *file_name; + union { + unsigned long reported; + struct { + u32 line; + u32 column; + }; + }; +}; + +struct overflow_data { + struct source_location location; + struct type_descriptor *type; +}; + +struct type_mismatch_data { + struct source_location location; + struct type_descriptor *type; + unsigned long alignment; + unsigned char type_check_kind; +}; + +struct nonnull_arg_data { + struct source_location location; + struct source_location attr_location; + int arg_index; +}; + +struct nonnull_return_data { + struct source_location location; + struct source_location attr_location; +}; + +struct vla_bound_data { + struct source_location location; + struct type_descriptor *type; +}; + +struct out_of_bounds_data { + struct source_location location; + struct type_descriptor *array_type; + struct type_descriptor *index_type; +}; + +struct shift_out_of_bounds_data { + struct source_location location; + struct type_descriptor *lhs_type; + struct type_descriptor *rhs_type; +}; + +struct unreachable_data { + struct source_location location; +}; + +struct invalid_value_data { + struct source_location location; + struct type_descriptor *type; +}; + +#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) +typedef __int128 s_max; +typedef unsigned __int128 u_max; +#else +typedef s64 s_max; +typedef u64 u_max; +#endif + +#endif |