kasan: decode stack frame only with KASAN_STACK_ENABLE
authorAndrey Konovalov <andreyknvl@google.com>
Tue, 22 Dec 2020 20:00:49 +0000 (12:00 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 22 Dec 2020 20:55:07 +0000 (12:55 -0800)
Decoding routines aren't needed when CONFIG_KASAN_STACK_ENABLE is not
enabled.  Currently only generic KASAN mode implements stack error
reporting.

No functional changes for software modes.

Link: https://lkml.kernel.org/r/05a24db36f5ec876af876a299bbea98c29468ebd.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/kasan/kasan.h
mm/kasan/report.c
mm/kasan/report_generic.c

index e5b5f60..488ca1f 100644 (file)
@@ -171,6 +171,12 @@ bool check_invalid_free(void *addr);
 void *find_first_bad_addr(void *addr, size_t size);
 const char *get_bug_type(struct kasan_access_info *info);
 
+#if defined(CONFIG_KASAN_GENERIC) && CONFIG_KASAN_STACK
+void print_address_stack_frame(const void *addr);
+#else
+static inline void print_address_stack_frame(const void *addr) { }
+#endif
+
 bool kasan_report(unsigned long addr, size_t size,
                bool is_write, unsigned long ip);
 void kasan_report_invalid_free(void *object, unsigned long ip);
index 96a7004..d140d26 100644 (file)
@@ -211,168 +211,6 @@ static inline bool init_task_stack_addr(const void *addr)
                        sizeof(init_thread_union.stack));
 }
 
-static bool __must_check tokenize_frame_descr(const char **frame_descr,
-                                             char *token, size_t max_tok_len,
-                                             unsigned long *value)
-{
-       const char *sep = strchr(*frame_descr, ' ');
-
-       if (sep == NULL)
-               sep = *frame_descr + strlen(*frame_descr);
-
-       if (token != NULL) {
-               const size_t tok_len = sep - *frame_descr;
-
-               if (tok_len + 1 > max_tok_len) {
-                       pr_err("KASAN internal error: frame description too long: %s\n",
-                              *frame_descr);
-                       return false;
-               }
-
-               /* Copy token (+ 1 byte for '\0'). */
-               strlcpy(token, *frame_descr, tok_len + 1);
-       }
-
-       /* Advance frame_descr past separator. */
-       *frame_descr = sep + 1;
-
-       if (value != NULL && kstrtoul(token, 10, value)) {
-               pr_err("KASAN internal error: not a valid number: %s\n", token);
-               return false;
-       }
-
-       return true;
-}
-
-static void print_decoded_frame_descr(const char *frame_descr)
-{
-       /*
-        * We need to parse the following string:
-        *    "n alloc_1 alloc_2 ... alloc_n"
-        * where alloc_i looks like
-        *    "offset size len name"
-        * or "offset size len name:line".
-        */
-
-       char token[64];
-       unsigned long num_objects;
-
-       if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
-                                 &num_objects))
-               return;
-
-       pr_err("\n");
-       pr_err("this frame has %lu %s:\n", num_objects,
-              num_objects == 1 ? "object" : "objects");
-
-       while (num_objects--) {
-               unsigned long offset;
-               unsigned long size;
-
-               /* access offset */
-               if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
-                                         &offset))
-                       return;
-               /* access size */
-               if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
-                                         &size))
-                       return;
-               /* name length (unused) */
-               if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL))
-                       return;
-               /* object name */
-               if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
-                                         NULL))
-                       return;
-
-               /* Strip line number; without filename it's not very helpful. */
-               strreplace(token, ':', '\0');
-
-               /* Finally, print object information. */
-               pr_err(" [%lu, %lu) '%s'", offset, offset + size, token);
-       }
-}
-
-static bool __must_check get_address_stack_frame_info(const void *addr,
-                                                     unsigned long *offset,
-                                                     const char **frame_descr,
-                                                     const void **frame_pc)
-{
-       unsigned long aligned_addr;
-       unsigned long mem_ptr;
-       const u8 *shadow_bottom;
-       const u8 *shadow_ptr;
-       const unsigned long *frame;
-
-       BUILD_BUG_ON(IS_ENABLED(CONFIG_STACK_GROWSUP));
-
-       /*
-        * NOTE: We currently only support printing frame information for
-        * accesses to the task's own stack.
-        */
-       if (!object_is_on_stack(addr))
-               return false;
-
-       aligned_addr = round_down((unsigned long)addr, sizeof(long));
-       mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE);
-       shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr);
-       shadow_bottom = kasan_mem_to_shadow(end_of_stack(current));
-
-       while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) {
-               shadow_ptr--;
-               mem_ptr -= KASAN_GRANULE_SIZE;
-       }
-
-       while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) {
-               shadow_ptr--;
-               mem_ptr -= KASAN_GRANULE_SIZE;
-       }
-
-       if (shadow_ptr < shadow_bottom)
-               return false;
-
-       frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE);
-       if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) {
-               pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n",
-                      frame[0]);
-               return false;
-       }
-
-       *offset = (unsigned long)addr - (unsigned long)frame;
-       *frame_descr = (const char *)frame[1];
-       *frame_pc = (void *)frame[2];
-
-       return true;
-}
-
-static void print_address_stack_frame(const void *addr)
-{
-       unsigned long offset;
-       const char *frame_descr;
-       const void *frame_pc;
-
-       if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
-               return;
-
-       if (!get_address_stack_frame_info(addr, &offset, &frame_descr,
-                                         &frame_pc))
-               return;
-
-       /*
-        * get_address_stack_frame_info only returns true if the given addr is
-        * on the current task's stack.
-        */
-       pr_err("\n");
-       pr_err("addr %px is located in stack of task %s/%d at offset %lu in frame:\n",
-              addr, current->comm, task_pid_nr(current), offset);
-       pr_err(" %pS\n", frame_pc);
-
-       if (!frame_descr)
-               return;
-
-       print_decoded_frame_descr(frame_descr);
-}
-
 static void print_address_description(void *addr, u8 tag)
 {
        struct page *page = kasan_addr_to_page(addr);
index 7d5b9e5..b543a1e 100644 (file)
@@ -16,6 +16,7 @@
 #include <linux/mm.h>
 #include <linux/printk.h>
 #include <linux/sched.h>
+#include <linux/sched/task_stack.h>
 #include <linux/slab.h>
 #include <linux/stackdepot.h>
 #include <linux/stacktrace.h>
@@ -122,6 +123,167 @@ const char *get_bug_type(struct kasan_access_info *info)
        return get_wild_bug_type(info);
 }
 
+#if CONFIG_KASAN_STACK
+static bool __must_check tokenize_frame_descr(const char **frame_descr,
+                                             char *token, size_t max_tok_len,
+                                             unsigned long *value)
+{
+       const char *sep = strchr(*frame_descr, ' ');
+
+       if (sep == NULL)
+               sep = *frame_descr + strlen(*frame_descr);
+
+       if (token != NULL) {
+               const size_t tok_len = sep - *frame_descr;
+
+               if (tok_len + 1 > max_tok_len) {
+                       pr_err("KASAN internal error: frame description too long: %s\n",
+                              *frame_descr);
+                       return false;
+               }
+
+               /* Copy token (+ 1 byte for '\0'). */
+               strlcpy(token, *frame_descr, tok_len + 1);
+       }
+
+       /* Advance frame_descr past separator. */
+       *frame_descr = sep + 1;
+
+       if (value != NULL && kstrtoul(token, 10, value)) {
+               pr_err("KASAN internal error: not a valid number: %s\n", token);
+               return false;
+       }
+
+       return true;
+}
+
+static void print_decoded_frame_descr(const char *frame_descr)
+{
+       /*
+        * We need to parse the following string:
+        *    "n alloc_1 alloc_2 ... alloc_n"
+        * where alloc_i looks like
+        *    "offset size len name"
+        * or "offset size len name:line".
+        */
+
+       char token[64];
+       unsigned long num_objects;
+
+       if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
+                                 &num_objects))
+               return;
+
+       pr_err("\n");
+       pr_err("this frame has %lu %s:\n", num_objects,
+              num_objects == 1 ? "object" : "objects");
+
+       while (num_objects--) {
+               unsigned long offset;
+               unsigned long size;
+
+               /* access offset */
+               if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
+                                         &offset))
+                       return;
+               /* access size */
+               if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
+                                         &size))
+                       return;
+               /* name length (unused) */
+               if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL))
+                       return;
+               /* object name */
+               if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
+                                         NULL))
+                       return;
+
+               /* Strip line number; without filename it's not very helpful. */
+               strreplace(token, ':', '\0');
+
+               /* Finally, print object information. */
+               pr_err(" [%lu, %lu) '%s'", offset, offset + size, token);
+       }
+}
+
+static bool __must_check get_address_stack_frame_info(const void *addr,
+                                                     unsigned long *offset,
+                                                     const char **frame_descr,
+                                                     const void **frame_pc)
+{
+       unsigned long aligned_addr;
+       unsigned long mem_ptr;
+       const u8 *shadow_bottom;
+       const u8 *shadow_ptr;
+       const unsigned long *frame;
+
+       BUILD_BUG_ON(IS_ENABLED(CONFIG_STACK_GROWSUP));
+
+       /*
+        * NOTE: We currently only support printing frame information for
+        * accesses to the task's own stack.
+        */
+       if (!object_is_on_stack(addr))
+               return false;
+
+       aligned_addr = round_down((unsigned long)addr, sizeof(long));
+       mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE);
+       shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr);
+       shadow_bottom = kasan_mem_to_shadow(end_of_stack(current));
+
+       while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) {
+               shadow_ptr--;
+               mem_ptr -= KASAN_GRANULE_SIZE;
+       }
+
+       while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) {
+               shadow_ptr--;
+               mem_ptr -= KASAN_GRANULE_SIZE;
+       }
+
+       if (shadow_ptr < shadow_bottom)
+               return false;
+
+       frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE);
+       if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) {
+               pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n",
+                      frame[0]);
+               return false;
+       }
+
+       *offset = (unsigned long)addr - (unsigned long)frame;
+       *frame_descr = (const char *)frame[1];
+       *frame_pc = (void *)frame[2];
+
+       return true;
+}
+
+void print_address_stack_frame(const void *addr)
+{
+       unsigned long offset;
+       const char *frame_descr;
+       const void *frame_pc;
+
+       if (!get_address_stack_frame_info(addr, &offset, &frame_descr,
+                                         &frame_pc))
+               return;
+
+       /*
+        * get_address_stack_frame_info only returns true if the given addr is
+        * on the current task's stack.
+        */
+       pr_err("\n");
+       pr_err("addr %px is located in stack of task %s/%d at offset %lu in frame:\n",
+              addr, current->comm, task_pid_nr(current), offset);
+       pr_err(" %pS\n", frame_pc);
+
+       if (!frame_descr)
+               return;
+
+       print_decoded_frame_descr(frame_descr);
+}
+#endif /* CONFIG_KASAN_STACK */
+
 #define DEFINE_ASAN_REPORT_LOAD(size)                     \
 void __asan_report_load##size##_noabort(unsigned long addr) \
 {                                                         \