On 9/18/20 10:45 AM, Sascha Hauer wrote: > - return block_prepare_used(control, block, adjust); > + void *ret; > + > + ret = block_prepare_used(control, block, adjust, size); > + if (!ret) > + return ret; > + > + return ret; Debugging leftover? You can just return the function result directly. > - return block_prepare_used(control, block, adjust); > + ret = block_prepare_used(control, block, adjust, size); > + if (!ret) > + return NULL; > + > + return ret; Likewise [snip] > diff --git a/lib/kasan/report.c b/lib/kasan/report.c > new file mode 100644 > index 0000000000..b7b2d032ee > --- /dev/null > +++ b/lib/kasan/report.c > @@ -0,0 +1,199 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This file contains common generic and tag-based KASAN error reporting code. > + * > + * Copyright (c) 2014 Samsung Electronics Co., Ltd. > + * Author: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> > + * > + * Some code borrowed from https://github.com/xairy/kasan-prototype by > + * Andrey Konovalov <andreyknvl@xxxxxxxxx> > + * > + * 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 <common.h> > +#include <linux/bitops.h> > +#include <linux/kernel.h> > +#include <printk.h> > +#include <asm-generic/sections.h> > + > +#include "kasan.h" > + > +/* Shadow layout customization. */ > +#define SHADOW_BYTES_PER_BLOCK 1 > +#define SHADOW_BLOCKS_PER_ROW 16 > +#define SHADOW_BYTES_PER_ROW (SHADOW_BLOCKS_PER_ROW * SHADOW_BYTES_PER_BLOCK) > +#define SHADOW_ROWS_AROUND_ADDR 2 > + > +static unsigned long kasan_flags; > + > +#define KASAN_BIT_REPORTED 0 > +#define KASAN_BIT_MULTI_SHOT 1 > + > +bool kasan_save_enable_multi_shot(void) > +{ > + return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); > +} > +EXPORT_SYMBOL_GPL(kasan_save_enable_multi_shot); > + > +void kasan_restore_multi_shot(bool enabled) > +{ > + if (!enabled) > + clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); > +} > +EXPORT_SYMBOL_GPL(kasan_restore_multi_shot); > + > +static void print_error_description(struct kasan_access_info *info) > +{ > + pr_err("BUG: KASAN: %s in %pS\n", > + get_bug_type(info), (void *)info->ip); > + pr_err("%s of size %zu at addr %px\n", > + info->is_write ? "Write" : "Read", info->access_size, > + info->access_addr); I just removed the pr_err in ubsan with this rationale: common: ubsan: replace pr_err with printf The pr_print family of functions also writes to the barebox log buffer, which we don't require for printing UBSan errors, which is a debugging aid. This also improves UBSan coverage as now undefined behavior within pr_print may be reported as well. Should we use plain printf here as well? Less code to execute = less chance to run into a recursion. > +} > + > +static void start_report(unsigned long *flags) > +{ > + /* > + * Make sure we don't end up in loop. > + */ > + kasan_disable_current(); > + pr_err("==================================================================\n"); > +} > + > +static void end_report(unsigned long *flags) > +{ > + pr_err("==================================================================\n"); > + kasan_enable_current(); > +} > + > +static inline bool kernel_or_module_addr(const void *addr) > +{ > + if (addr >= (void *)_stext && addr < (void *)_end) > + return true; > + return false; > +} > + > +static void print_address_description(void *addr, u8 tag) > +{ > + dump_stack(); > + pr_err("\n"); > + > + if (kernel_or_module_addr(addr)) { > + pr_err("The buggy address belongs to the variable:\n"); > + pr_err(" %pS\n", addr); > + } > +} > + > +static bool row_is_guilty(const void *row, const void *guilty) > +{ > + return (row <= guilty) && (guilty < row + SHADOW_BYTES_PER_ROW); > +} > + > +static int shadow_pointer_offset(const void *row, const void *shadow) > +{ > + /* The length of ">ff00ff00ff00ff00: " is > + * 3 + (BITS_PER_LONG/8)*2 chars. > + */ > + return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 + > + (shadow - row) / SHADOW_BYTES_PER_BLOCK + 1; > +} > + > +static void print_shadow_for_address(const void *addr) > +{ > + int i; > + const void *shadow = kasan_mem_to_shadow(addr); > + const void *shadow_row; > + > + shadow_row = (void *)round_down((unsigned long)shadow, > + SHADOW_BYTES_PER_ROW) > + - SHADOW_ROWS_AROUND_ADDR * SHADOW_BYTES_PER_ROW; > + > + pr_err("Memory state around the buggy address:\n"); > + > + for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) { > + const void *kaddr = kasan_shadow_to_mem(shadow_row); > + char buffer[4 + (BITS_PER_LONG/8)*2]; > + char shadow_buf[SHADOW_BYTES_PER_ROW]; > + > + snprintf(buffer, sizeof(buffer), > + (i == 0) ? ">%px: " : " %px: ", kaddr); > + /* > + * We should not pass a shadow pointer to generic > + * function, because generic functions may try to > + * access kasan mapping for the passed address. > + */ > + memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW); > + print_hex_dump(KERN_ERR, buffer, > + DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1, > + shadow_buf, SHADOW_BYTES_PER_ROW, 0); > + > + if (row_is_guilty(shadow_row, shadow)) > + printf("%*c\n", > + shadow_pointer_offset(shadow_row, shadow), > + '^'); > + > + shadow_row += SHADOW_BYTES_PER_ROW; > + } > +} > + > +static bool report_enabled(void) > +{ > + if (kasan_depth) > + return false; > + if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags)) > + return true; > + return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags); > +} > + > +static void __kasan_report(unsigned long addr, size_t size, bool is_write, > + unsigned long ip) > +{ > + struct kasan_access_info info; > + void *tagged_addr; > + void *untagged_addr; > + unsigned long flags; > + > + tagged_addr = (void *)addr; > + untagged_addr = reset_tag(tagged_addr); > + > + info.access_addr = tagged_addr; > + if (addr_has_shadow(untagged_addr)) > + info.first_bad_addr = find_first_bad_addr(tagged_addr, size); > + else > + info.first_bad_addr = untagged_addr; > + info.access_size = size; > + info.is_write = is_write; > + info.ip = ip; > + > + start_report(&flags); > + > + print_error_description(&info); > + pr_err("\n"); > + > + if (addr_has_shadow(untagged_addr)) { > + print_address_description(untagged_addr, get_tag(tagged_addr)); > + pr_err("\n"); > + print_shadow_for_address(info.first_bad_addr); > + } else { > + dump_stack(); > + } > + > + end_report(&flags); > +} > + > +bool kasan_report(unsigned long addr, size_t size, bool is_write, > + unsigned long ip) > +{ > + bool ret = false; > + > + if (likely(report_enabled())) { > + __kasan_report(addr, size, is_write, ip); > + ret = true; > + } > + > + return ret; > +} > diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan > new file mode 100644 > index 0000000000..83f6aa543d > --- /dev/null > +++ b/scripts/Makefile.kasan > @@ -0,0 +1,17 @@ > + # SPDX-License-Identifier: GPL-2.0 > +ifdef CONFIG_KASAN > +CFLAGS_KASAN_NOSANITIZE := -fno-builtin > +KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET) > +endif > + > +CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address > + > +cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1))) > + > +CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL) \ > + $(call cc-param,asan-globals=1) \ > + $(call cc-param,asan-instrument-allocas=1) > + > +ifndef CONFIG_CPU_64 > +CFLAGS_KASAN += $(call cc-param,asan-stack=1) > +endif > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > index 337430cd00..ab7d9f2bdf 100644 > --- a/scripts/Makefile.lib > +++ b/scripts/Makefile.lib > @@ -127,6 +127,16 @@ _c_flags = $(KBUILD_CFLAGS) $(ccflags-y) $(CFLAGS_$(target-stem).o) > _a_flags = $(KBUILD_AFLAGS) $(asflags-y) $(AFLAGS_$(target-stem).o) > _cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(target-stem).lds) > > +# > +# Enable address sanitizer flags for kernel except some files or directories > +# we don't want to check (depends on variables KASAN_SANITIZE_obj.o, KASAN_SANITIZE) > +# > +ifeq ($(CONFIG_KASAN),y) > +_c_flags += $(if $(part-of-pbl),, $(if $(patsubst n%,, \ > + $(KASAN_SANITIZE_$(basetarget).o)$(KASAN_SANITIZE)y), \ > + $(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))) > +endif > + > ifeq ($(CONFIG_UBSAN),y) > _CFLAGS_UBSAN = $(eval _CFLAGS_UBSAN := $(CFLAGS_UBSAN))$(_CFLAGS_UBSAN) > _c_flags += $(if $(patsubst n%,, \ > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
