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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Kees Cook](/assets/img/avatar_default.png)
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@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.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> Link: http://lkml.kernel.org/r/20200227193516.32566-7-keescook@chromium.org Link: https://lore.kernel.org/lkml/CACT4Y+bsLJ-wFx_TaXqax3JByUOWB3uk787LsyMVcfW6JzzGvg@mail.gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
428 lines
10 KiB
C
428 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* UBSAN error reporting functions
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*
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* Copyright (c) 2014 Samsung Electronics Co., Ltd.
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* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
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*/
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#include <linux/bitops.h>
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#include <linux/bug.h>
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#include <linux/ctype.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/uaccess.h>
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#include "ubsan.h"
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const char *type_check_kinds[] = {
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"load of",
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"store to",
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"reference binding to",
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"member access within",
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"member call on",
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"constructor call on",
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"downcast of",
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"downcast of"
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};
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#define REPORTED_BIT 31
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#if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN)
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#define COLUMN_MASK (~(1U << REPORTED_BIT))
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#define LINE_MASK (~0U)
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#else
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#define COLUMN_MASK (~0U)
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#define LINE_MASK (~(1U << REPORTED_BIT))
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#endif
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#define VALUE_LENGTH 40
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static bool was_reported(struct source_location *location)
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{
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return test_and_set_bit(REPORTED_BIT, &location->reported);
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}
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static bool suppress_report(struct source_location *loc)
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{
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return current->in_ubsan || was_reported(loc);
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}
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static bool type_is_int(struct type_descriptor *type)
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{
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return type->type_kind == type_kind_int;
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}
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static bool type_is_signed(struct type_descriptor *type)
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{
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WARN_ON(!type_is_int(type));
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return type->type_info & 1;
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}
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static unsigned type_bit_width(struct type_descriptor *type)
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{
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return 1 << (type->type_info >> 1);
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}
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static bool is_inline_int(struct type_descriptor *type)
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{
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unsigned inline_bits = sizeof(unsigned long)*8;
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unsigned bits = type_bit_width(type);
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WARN_ON(!type_is_int(type));
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return bits <= inline_bits;
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}
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static s_max get_signed_val(struct type_descriptor *type, void *val)
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{
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if (is_inline_int(type)) {
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unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type);
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unsigned long ulong_val = (unsigned long)val;
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return ((s_max)ulong_val) << extra_bits >> extra_bits;
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}
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if (type_bit_width(type) == 64)
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return *(s64 *)val;
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return *(s_max *)val;
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}
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static bool val_is_negative(struct type_descriptor *type, void *val)
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{
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return type_is_signed(type) && get_signed_val(type, val) < 0;
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}
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static u_max get_unsigned_val(struct type_descriptor *type, void *val)
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{
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if (is_inline_int(type))
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return (unsigned long)val;
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if (type_bit_width(type) == 64)
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return *(u64 *)val;
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return *(u_max *)val;
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}
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static void val_to_string(char *str, size_t size, struct type_descriptor *type,
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void *value)
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{
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if (type_is_int(type)) {
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if (type_bit_width(type) == 128) {
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#if defined(CONFIG_ARCH_SUPPORTS_INT128)
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u_max val = get_unsigned_val(type, value);
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scnprintf(str, size, "0x%08x%08x%08x%08x",
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(u32)(val >> 96),
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(u32)(val >> 64),
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(u32)(val >> 32),
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(u32)(val));
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#else
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WARN_ON(1);
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#endif
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} else if (type_is_signed(type)) {
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scnprintf(str, size, "%lld",
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(s64)get_signed_val(type, value));
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} else {
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scnprintf(str, size, "%llu",
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(u64)get_unsigned_val(type, value));
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}
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}
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}
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static void ubsan_prologue(struct source_location *loc, const char *reason)
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{
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current->in_ubsan++;
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pr_err("========================================"
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"========================================\n");
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pr_err("UBSAN: %s in %s:%d:%d\n", reason, loc->file_name,
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loc->line & LINE_MASK, loc->column & COLUMN_MASK);
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}
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static void ubsan_epilogue(void)
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{
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dump_stack();
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pr_err("========================================"
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"========================================\n");
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current->in_ubsan--;
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if (panic_on_warn) {
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/*
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* This thread may hit another WARN() in the panic path.
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* Resetting this prevents additional WARN() from panicking the
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* system on this thread. Other threads are blocked by the
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* panic_mutex in panic().
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*/
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panic_on_warn = 0;
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panic("panic_on_warn set ...\n");
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}
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}
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static void handle_overflow(struct overflow_data *data, void *lhs,
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void *rhs, char op)
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{
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struct type_descriptor *type = data->type;
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char lhs_val_str[VALUE_LENGTH];
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char rhs_val_str[VALUE_LENGTH];
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if (suppress_report(&data->location))
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return;
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ubsan_prologue(&data->location, type_is_signed(type) ?
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"signed-integer-overflow" :
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"unsigned-integer-overflow");
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val_to_string(lhs_val_str, sizeof(lhs_val_str), type, lhs);
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val_to_string(rhs_val_str, sizeof(rhs_val_str), type, rhs);
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pr_err("%s %c %s cannot be represented in type %s\n",
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lhs_val_str,
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op,
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rhs_val_str,
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type->type_name);
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ubsan_epilogue();
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}
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void __ubsan_handle_add_overflow(struct overflow_data *data,
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void *lhs, void *rhs)
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{
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handle_overflow(data, lhs, rhs, '+');
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}
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EXPORT_SYMBOL(__ubsan_handle_add_overflow);
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void __ubsan_handle_sub_overflow(struct overflow_data *data,
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void *lhs, void *rhs)
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{
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handle_overflow(data, lhs, rhs, '-');
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}
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EXPORT_SYMBOL(__ubsan_handle_sub_overflow);
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void __ubsan_handle_mul_overflow(struct overflow_data *data,
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void *lhs, void *rhs)
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{
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handle_overflow(data, lhs, rhs, '*');
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}
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EXPORT_SYMBOL(__ubsan_handle_mul_overflow);
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void __ubsan_handle_negate_overflow(struct overflow_data *data,
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void *old_val)
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{
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char old_val_str[VALUE_LENGTH];
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if (suppress_report(&data->location))
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return;
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ubsan_prologue(&data->location, "negation-overflow");
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val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val);
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pr_err("negation of %s cannot be represented in type %s:\n",
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old_val_str, data->type->type_name);
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ubsan_epilogue();
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}
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EXPORT_SYMBOL(__ubsan_handle_negate_overflow);
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void __ubsan_handle_divrem_overflow(struct overflow_data *data,
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void *lhs, void *rhs)
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{
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char rhs_val_str[VALUE_LENGTH];
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if (suppress_report(&data->location))
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return;
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ubsan_prologue(&data->location, "division-overflow");
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val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs);
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if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1)
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pr_err("division of %s by -1 cannot be represented in type %s\n",
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rhs_val_str, data->type->type_name);
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else
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pr_err("division by zero\n");
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ubsan_epilogue();
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}
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EXPORT_SYMBOL(__ubsan_handle_divrem_overflow);
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static void handle_null_ptr_deref(struct type_mismatch_data_common *data)
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{
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if (suppress_report(data->location))
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return;
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ubsan_prologue(data->location, "null-ptr-deref");
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pr_err("%s null pointer of type %s\n",
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type_check_kinds[data->type_check_kind],
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data->type->type_name);
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ubsan_epilogue();
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}
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static void handle_misaligned_access(struct type_mismatch_data_common *data,
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unsigned long ptr)
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{
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if (suppress_report(data->location))
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return;
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ubsan_prologue(data->location, "misaligned-access");
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pr_err("%s misaligned address %p for type %s\n",
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type_check_kinds[data->type_check_kind],
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(void *)ptr, data->type->type_name);
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pr_err("which requires %ld byte alignment\n", data->alignment);
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ubsan_epilogue();
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}
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static void handle_object_size_mismatch(struct type_mismatch_data_common *data,
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unsigned long ptr)
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{
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if (suppress_report(data->location))
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return;
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ubsan_prologue(data->location, "object-size-mismatch");
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pr_err("%s address %p with insufficient space\n",
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type_check_kinds[data->type_check_kind],
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(void *) ptr);
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pr_err("for an object of type %s\n", data->type->type_name);
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ubsan_epilogue();
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}
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static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data,
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unsigned long ptr)
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{
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unsigned long flags = user_access_save();
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if (!ptr)
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handle_null_ptr_deref(data);
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else if (data->alignment && !IS_ALIGNED(ptr, data->alignment))
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handle_misaligned_access(data, ptr);
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else
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handle_object_size_mismatch(data, ptr);
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user_access_restore(flags);
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}
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void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
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void *ptr)
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{
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struct type_mismatch_data_common common_data = {
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.location = &data->location,
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.type = data->type,
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.alignment = data->alignment,
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.type_check_kind = data->type_check_kind
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};
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ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
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}
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EXPORT_SYMBOL(__ubsan_handle_type_mismatch);
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void __ubsan_handle_type_mismatch_v1(struct type_mismatch_data_v1 *data,
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void *ptr)
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{
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struct type_mismatch_data_common common_data = {
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.location = &data->location,
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.type = data->type,
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.alignment = 1UL << data->log_alignment,
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.type_check_kind = data->type_check_kind
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};
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ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
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}
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EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1);
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void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data, void *index)
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{
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char index_str[VALUE_LENGTH];
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if (suppress_report(&data->location))
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return;
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ubsan_prologue(&data->location, "array-index-out-of-bounds");
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val_to_string(index_str, sizeof(index_str), data->index_type, index);
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pr_err("index %s is out of range for type %s\n", index_str,
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data->array_type->type_name);
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ubsan_epilogue();
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}
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EXPORT_SYMBOL(__ubsan_handle_out_of_bounds);
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void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
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void *lhs, void *rhs)
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{
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struct type_descriptor *rhs_type = data->rhs_type;
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struct type_descriptor *lhs_type = data->lhs_type;
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char rhs_str[VALUE_LENGTH];
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char lhs_str[VALUE_LENGTH];
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unsigned long ua_flags = user_access_save();
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if (suppress_report(&data->location))
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goto out;
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ubsan_prologue(&data->location, "shift-out-of-bounds");
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val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs);
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val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs);
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if (val_is_negative(rhs_type, rhs))
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pr_err("shift exponent %s is negative\n", rhs_str);
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else if (get_unsigned_val(rhs_type, rhs) >=
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type_bit_width(lhs_type))
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pr_err("shift exponent %s is too large for %u-bit type %s\n",
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rhs_str,
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type_bit_width(lhs_type),
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lhs_type->type_name);
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else if (val_is_negative(lhs_type, lhs))
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pr_err("left shift of negative value %s\n",
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lhs_str);
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else
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pr_err("left shift of %s by %s places cannot be"
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" represented in type %s\n",
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lhs_str, rhs_str,
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lhs_type->type_name);
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ubsan_epilogue();
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out:
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user_access_restore(ua_flags);
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}
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EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
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void __ubsan_handle_builtin_unreachable(struct unreachable_data *data)
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{
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ubsan_prologue(&data->location, "unreachable");
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pr_err("calling __builtin_unreachable()\n");
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ubsan_epilogue();
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panic("can't return from __builtin_unreachable()");
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}
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EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
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void __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
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void *val)
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{
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char val_str[VALUE_LENGTH];
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if (suppress_report(&data->location))
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return;
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ubsan_prologue(&data->location, "invalid-load");
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val_to_string(val_str, sizeof(val_str), data->type, val);
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pr_err("load of value %s is not a valid value for type %s\n",
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val_str, data->type->type_name);
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ubsan_epilogue();
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}
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EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);
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