diff options
| -rw-r--r-- | bcheck.c | 90 |
1 files changed, 71 insertions, 19 deletions
@@ -54,9 +54,9 @@ typedef struct BoundEntry { /* external interface */ void __bound_init(void); void __bound_new_region(void *p, unsigned long size); -void __bound_delete_region(void *p); +int __bound_delete_region(void *p); -/* currently, tcc cannot compile that because we use unsupported GNUC +/* currently, tcc cannot compile that because we use unsupported GNU C extensions */ #if !defined(__TINYC__) void *__bound_ptr_add(void *p, int offset) __attribute__((regparm(2))); @@ -69,6 +69,7 @@ void *__bound_ptr_indir16(void *p, int offset) __attribute__((regparm(2))); void __bound_local_new(void *p) __attribute__((regparm(1))); void __bound_local_delete(void *p) __attribute__((regparm(1))); #endif +static void *get_caller_pc(int n); void *__bound_malloc(size_t size, const void *caller); void *__bound_memalign(size_t size, size_t align, const void *caller); @@ -122,20 +123,16 @@ static BoundEntry *__bound_find_region(BoundEntry *e1, void *p) return __bound_empty_t2; } -static void bound_error(const char *fmt, ...) +/* print a bound error and recurse thru 'nb_callers' to get the error + position */ +static void bound_error(const void *caller, const char *fmt, ...) { - va_list ap; - va_start(ap, fmt); - fprintf(stderr, "bounds check: "); - vfprintf(stderr, fmt, ap); - fprintf(stderr, "\n"); - exit(1); - va_end(ap); + rt_error((unsigned long)caller, "%s", fmt); } static void bound_alloc_error(void) { - bound_error("not enough memory for bound checking code\n"); + bound_error(NULL, "not enough memory for bound checking code\n"); } /* currently, tcc cannot compile that because we use GNUC extensions */ @@ -190,6 +187,20 @@ void *__bound_ptr_indir ## dsize (void *p, int offset) \ } #ifdef __i386__ + +/* return the PC of the N'th caller (N=1: first caller) */ +static void *get_caller_pc(int n) +{ + unsigned long fp; + int i; + + __asm__ __volatile__ ("movl %%ebp,%0" :"=g" (fp)); + for(i=0;i<n;i++) + fp = ((unsigned long *)fp)[0]; + return ((void **)fp)[1]; +} + +/* return the frame pointer of the caller */ #define GET_CALLER_FP(fp)\ {\ unsigned long *fp1;\ @@ -251,6 +262,10 @@ void *__bound_ptr_indir ## dsize (void *p, int offset) \ return p + offset; \ } +static void *get_caller_pc(int n) +{ + return 0; +} #endif BOUND_PTR_INDIR(1) @@ -527,7 +542,8 @@ static inline void delete_region(BoundEntry *e, } /* WARNING: 'p' must be the starting point of the region. */ -void __bound_delete_region(void *p) +/* return non zero if error */ +int __bound_delete_region(void *p) { unsigned long start, end, addr, size, empty_size; BoundEntry *page, *e, *e2; @@ -546,7 +562,7 @@ void __bound_delete_region(void *p) e = __bound_find_region(e, p); /* test if invalid region */ if (e->size == EMPTY_SIZE || (unsigned long)p != e->start) - bound_error("freeing invalid region"); + return -1; /* compute the size we put in invalid regions */ if (e->is_invalid) empty_size = INVALID_SIZE; @@ -599,6 +615,7 @@ void __bound_delete_region(void *p) } delete_region(e, p, empty_size); } + return 0; } /* return the size of the region starting at p, or EMPTY_SIZE if non @@ -699,7 +716,8 @@ void __bound_free(void *ptr, const void *caller) { if (ptr == NULL) return; - __bound_delete_region(ptr); + if (__bound_delete_region(ptr) != 0) + bound_error(caller, "freeing invalid region"); libc_free(ptr); } @@ -718,7 +736,7 @@ void *__bound_realloc(void *ptr, size_t size, const void *caller) return ptr1; old_size = get_region_size(ptr); if (old_size == EMPTY_SIZE) - bound_error("realloc'ing invalid pointer"); + bound_error(caller, "realloc'ing invalid pointer"); memcpy(ptr1, ptr, old_size); __bound_free(ptr, caller); return ptr1; @@ -752,7 +770,41 @@ static void bound_dump(void) } #endif -#if 0 +/* some useful checked functions */ + +/* check that (p ... p + size - 1) lies inside 'p' region, if any */ +static void __bound_check(const void *p, ssize_t size) +{ + if (size == 0) + return; + p = __bound_ptr_add((void *)p, size); + if (p == INVALID_POINTER) + bound_error(get_caller_pc(2), "invalid pointer"); +} + +void *__bound_memcpy(void *dst, const void *src, size_t size) +{ + __bound_check(dst, size); + __bound_check(src, size); + /* check also region overlap */ + if (src >= dst && src < dst + size) + bound_error(get_caller_pc(1), "memcpy: overlapping regions"); + return memcpy(dst, src, size); +} + +void *__bound_memmove(void *dst, const void *src, size_t size) +{ + __bound_check(dst, size); + __bound_check(src, size); + return memmove(dst, src, size); +} + +void *__bound_memset(void *dst, int c, size_t size) +{ + __bound_check(dst, size); + return memset(dst, 0, size); +} + /* resolve check check syms */ typedef struct BCSyms { char *str; @@ -760,13 +812,14 @@ typedef struct BCSyms { } BCSyms; static BCSyms bcheck_syms[] = { + { "memcpy", __bound_memcpy }, + { "memmove", __bound_memmove }, + { "memset", __bound_memset }, { NULL, NULL }, }; -#endif static void *bound_resolve_sym(const char *sym) { -#if 0 BCSyms *p; p = bcheck_syms; while (p->str != NULL) { @@ -774,6 +827,5 @@ static void *bound_resolve_sym(const char *sym) return p->ptr; p++; } -#endif return NULL; } |