[PATCH v4 1/9] kasan: introduce helper functions for determining bug type
From: Andrey Konovalov <hidden>
Date: 2017-03-28 14:01:21
Subsystem:
kasan, memory management, the rest · Maintainers:
Andrey Ryabinin, Andrew Morton, Linus Torvalds
Introduce get_shadow_bug_type() function, which determines bug type based on the shadow value for a particular kernel address. Introduce get_wild_bug_type() function, which determines bug type for addresses which don't have a corresponding shadow value. Signed-off-by: Andrey Konovalov <redacted> --- mm/kasan/report.c | 40 ++++++++++++++++++++++++++++++---------- 1 file changed, 30 insertions(+), 10 deletions(-)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index f479365530b6..e3af37b7a74c 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c@@ -49,7 +49,13 @@ static const void *find_first_bad_addr(const void *addr, size_t size) return first_bad_addr; } -static void print_error_description(struct kasan_access_info *info) +static bool addr_has_shadow(struct kasan_access_info *info) +{ + return (info->access_addr >= + kasan_shadow_to_mem((void *)KASAN_SHADOW_START)); +} + +static const char *get_shadow_bug_type(struct kasan_access_info *info) { const char *bug_type = "unknown-crash"; u8 *shadow_addr;
@@ -96,6 +102,27 @@ static void print_error_description(struct kasan_access_info *info) break; } + return bug_type; +} + +static const char *get_wild_bug_type(struct kasan_access_info *info) +{ + const char *bug_type; + + if ((unsigned long)info->access_addr < PAGE_SIZE) + bug_type = "null-ptr-deref"; + else if ((unsigned long)info->access_addr < TASK_SIZE) + bug_type = "user-memory-access"; + else + bug_type = "wild-memory-access"; + + return bug_type; +} + +static void print_error_description(struct kasan_access_info *info) +{ + const char *bug_type = get_shadow_bug_type(info); + pr_err("BUG: KASAN: %s in %pS at addr %p\n", bug_type, (void *)info->ip, info->access_addr);
@@ -265,18 +292,11 @@ static void print_shadow_for_address(const void *addr) static void kasan_report_error(struct kasan_access_info *info) { unsigned long flags; - const char *bug_type; kasan_start_report(&flags); - if (info->access_addr < - kasan_shadow_to_mem((void *)KASAN_SHADOW_START)) { - if ((unsigned long)info->access_addr < PAGE_SIZE) - bug_type = "null-ptr-deref"; - else if ((unsigned long)info->access_addr < TASK_SIZE) - bug_type = "user-memory-access"; - else - bug_type = "wild-memory-access"; + if (!addr_has_shadow(info)) { + const char *bug_type = get_wild_bug_type(info); pr_err("BUG: KASAN: %s on address %p\n", bug_type, info->access_addr); pr_err("%s of size %zu by task %s/%d\n",
--
2.12.1.578.ge9c3154ca4-goog