This commit adds rountines, that print KHWASAN error reports. Those are quite similar to KASAN, the difference is:
1. The way KHWASAN finds the first bad shadow cell (with a mismatching tag). KHWASAN compares memory tags from the shadow memory to the pointer tag. 2. KHWASAN reports all bugs with the "KASAN: invalid-access" header. This is done, so various external tools that already parse the kernel logs looking for KASAN reports wouldn't need to be changed. Signed-off-by: Andrey Konovalov <[email protected]> --- include/linux/kasan.h | 3 +++ mm/kasan/kasan.h | 7 +++++ mm/kasan/kasan_report.c | 7 ++--- mm/kasan/khwasan_report.c | 21 +++++++++++++++ mm/kasan/report.c | 57 +++++++++++++++++++++------------------ 5 files changed, 64 insertions(+), 31 deletions(-) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index d7624b879d86..e209027f3b52 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -161,6 +161,9 @@ void *khwasan_set_tag(const void *addr, u8 tag); u8 khwasan_get_tag(const void *addr); void *khwasan_reset_tag(const void *ptr); +void kasan_report(unsigned long addr, size_t size, + bool write, unsigned long ip); + #else /* CONFIG_KASAN_HW */ static inline void khwasan_init(void) { } diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index a76aee9e095f..620941d1e84f 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -128,8 +128,15 @@ void kasan_poison_shadow(const void *address, size_t size, u8 value); void check_memory_region(unsigned long addr, size_t size, bool write, unsigned long ret_ip); +void *find_first_bad_addr(void *addr, size_t size); const char *get_bug_type(struct kasan_access_info *info); +#ifdef CONFIG_KASAN_HW +void print_tags(u8 addr_tag, const void *addr); +#else +static inline void print_tags(u8 addr_tag, const void *addr) { } +#endif + void kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip); void kasan_report_invalid_free(void *object, unsigned long ip); diff --git a/mm/kasan/kasan_report.c b/mm/kasan/kasan_report.c index 2d8decbecbd5..fdf2d77e3125 100644 --- a/mm/kasan/kasan_report.c +++ b/mm/kasan/kasan_report.c @@ -33,10 +33,10 @@ #include "kasan.h" #include "../slab.h" -static const void *find_first_bad_addr(const void *addr, size_t size) +void *find_first_bad_addr(void *addr, size_t size) { u8 shadow_val = *(u8 *)kasan_mem_to_shadow(addr); - const void *first_bad_addr = addr; + void *first_bad_addr = addr; while (!shadow_val && first_bad_addr < addr + size) { first_bad_addr += KASAN_SHADOW_SCALE_SIZE; @@ -50,9 +50,6 @@ static const char *get_shadow_bug_type(struct kasan_access_info *info) const char *bug_type = "unknown-crash"; u8 *shadow_addr; - info->first_bad_addr = find_first_bad_addr(info->access_addr, - info->access_size); - shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr); /* diff --git a/mm/kasan/khwasan_report.c b/mm/kasan/khwasan_report.c index 2edbc3c76be5..51238b404b08 100644 --- a/mm/kasan/khwasan_report.c +++ b/mm/kasan/khwasan_report.c @@ -37,3 +37,24 @@ const char *get_bug_type(struct kasan_access_info *info) { return "invalid-access"; } + +void *find_first_bad_addr(void *addr, size_t size) +{ + u8 tag = get_tag(addr); + void *untagged_addr = reset_tag(addr); + u8 *shadow = (u8 *)kasan_mem_to_shadow(untagged_addr); + void *first_bad_addr = untagged_addr; + + while (*shadow == tag && first_bad_addr < untagged_addr + size) { + first_bad_addr += KASAN_SHADOW_SCALE_SIZE; + shadow = (u8 *)kasan_mem_to_shadow(first_bad_addr); + } + return first_bad_addr; +} + +void print_tags(u8 addr_tag, const void *addr) +{ + u8 *shadow = (u8 *)kasan_mem_to_shadow(addr); + + pr_err("Pointer tag: [%02x], memory tag: [%02x]\n", addr_tag, *shadow); +} diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 155247a6f8a8..e031c78f2e52 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -64,11 +64,10 @@ static int __init kasan_set_multi_shot(char *str) } __setup("kasan_multi_shot", kasan_set_multi_shot); -static void print_error_description(struct kasan_access_info *info, - const char *bug_type) +static void print_error_description(struct kasan_access_info *info) { pr_err("BUG: KASAN: %s in %pS\n", - bug_type, (void *)info->ip); + get_bug_type(info), (void *)info->ip); pr_err("%s of size %zu at addr %px by task %s/%d\n", info->is_write ? "Write" : "Read", info->access_size, info->access_addr, current->comm, task_pid_nr(current)); @@ -272,6 +271,8 @@ void kasan_report_invalid_free(void *object, unsigned long ip) start_report(&flags); pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", (void *)ip); + print_tags(get_tag(object), reset_tag(object)); + object = reset_tag(object); pr_err("\n"); print_address_description(object); pr_err("\n"); @@ -279,41 +280,45 @@ void kasan_report_invalid_free(void *object, unsigned long ip) end_report(&flags); } -static void kasan_report_error(struct kasan_access_info *info) -{ - unsigned long flags; - - start_report(&flags); - - print_error_description(info, get_bug_type(info)); - pr_err("\n"); - - if (!addr_has_shadow(info->access_addr)) { - dump_stack(); - } else { - print_address_description((void *)info->access_addr); - pr_err("\n"); - print_shadow_for_address(info->first_bad_addr); - } - - end_report(&flags); -} - 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; if (likely(!report_enabled())) return; disable_trace_on_warning(); - info.access_addr = (void *)addr; - info.first_bad_addr = (void *)addr; + 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; - kasan_report_error(&info); + start_report(&flags); + + print_error_description(&info); + if (addr_has_shadow(untagged_addr)) + print_tags(get_tag(tagged_addr), info.first_bad_addr); + pr_err("\n"); + + if (addr_has_shadow(untagged_addr)) { + print_address_description(untagged_addr); + pr_err("\n"); + print_shadow_for_address(info.first_bad_addr); + } else { + dump_stack(); + } + + end_report(&flags); } -- 2.17.0.484.g0c8726318c-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
