1 //===-- asan_malloc_linux.cc ----------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is a part of AddressSanitizer, an address sanity checker.
11 //
12 // Linux-specific malloc interception.
13 // We simply define functions like malloc, free, realloc, etc.
14 // They will replace the corresponding libc functions automagically.
15 //===----------------------------------------------------------------------===//
16 
17 #include "sanitizer_common/sanitizer_platform.h"
18 #if SANITIZER_FREEBSD || SANITIZER_LINUX
19 
20 #include "sanitizer_common/sanitizer_tls_get_addr.h"
21 #include "asan_allocator.h"
22 #include "asan_interceptors.h"
23 #include "asan_internal.h"
24 #include "asan_stack.h"
25 
26 // ---------------------- Replacement functions ---------------- {{{1
27 using namespace __asan;  // NOLINT
28 
INTERCEPTOR(void,free,void * ptr)29 INTERCEPTOR(void, free, void *ptr) {
30   GET_STACK_TRACE_FREE;
31   asan_free(ptr, &stack, FROM_MALLOC);
32 }
33 
INTERCEPTOR(void,cfree,void * ptr)34 INTERCEPTOR(void, cfree, void *ptr) {
35   GET_STACK_TRACE_FREE;
36   asan_free(ptr, &stack, FROM_MALLOC);
37 }
38 
INTERCEPTOR(void *,malloc,uptr size)39 INTERCEPTOR(void*, malloc, uptr size) {
40   GET_STACK_TRACE_MALLOC;
41   return asan_malloc(size, &stack);
42 }
43 
INTERCEPTOR(void *,calloc,uptr nmemb,uptr size)44 INTERCEPTOR(void*, calloc, uptr nmemb, uptr size) {
45   if (UNLIKELY(!asan_inited)) {
46     // Hack: dlsym calls calloc before REAL(calloc) is retrieved from dlsym.
47     const uptr kCallocPoolSize = 1024;
48     static uptr calloc_memory_for_dlsym[kCallocPoolSize];
49     static uptr allocated;
50     uptr size_in_words = ((nmemb * size) + kWordSize - 1) / kWordSize;
51     void *mem = (void*)&calloc_memory_for_dlsym[allocated];
52     allocated += size_in_words;
53     CHECK(allocated < kCallocPoolSize);
54     return mem;
55   }
56   GET_STACK_TRACE_MALLOC;
57   return asan_calloc(nmemb, size, &stack);
58 }
59 
INTERCEPTOR(void *,realloc,void * ptr,uptr size)60 INTERCEPTOR(void*, realloc, void *ptr, uptr size) {
61   GET_STACK_TRACE_MALLOC;
62   return asan_realloc(ptr, size, &stack);
63 }
64 
INTERCEPTOR(void *,memalign,uptr boundary,uptr size)65 INTERCEPTOR(void*, memalign, uptr boundary, uptr size) {
66   GET_STACK_TRACE_MALLOC;
67   return asan_memalign(boundary, size, &stack, FROM_MALLOC);
68 }
69 
INTERCEPTOR(void *,aligned_alloc,uptr boundary,uptr size)70 INTERCEPTOR(void*, aligned_alloc, uptr boundary, uptr size) {
71   GET_STACK_TRACE_MALLOC;
72   return asan_memalign(boundary, size, &stack, FROM_MALLOC);
73 }
74 
INTERCEPTOR(void *,__libc_memalign,uptr boundary,uptr size)75 INTERCEPTOR(void*, __libc_memalign, uptr boundary, uptr size) {
76   GET_STACK_TRACE_MALLOC;
77   void *res = asan_memalign(boundary, size, &stack, FROM_MALLOC);
78   DTLS_on_libc_memalign(res, size * boundary);
79   return res;
80 }
81 
INTERCEPTOR(uptr,malloc_usable_size,void * ptr)82 INTERCEPTOR(uptr, malloc_usable_size, void *ptr) {
83   GET_CURRENT_PC_BP_SP;
84   (void)sp;
85   return asan_malloc_usable_size(ptr, pc, bp);
86 }
87 
88 // We avoid including malloc.h for portability reasons.
89 // man mallinfo says the fields are "long", but the implementation uses int.
90 // It doesn't matter much -- we just need to make sure that the libc's mallinfo
91 // is not called.
92 struct fake_mallinfo {
93   int x[10];
94 };
95 
INTERCEPTOR(struct fake_mallinfo,mallinfo,void)96 INTERCEPTOR(struct fake_mallinfo, mallinfo, void) {
97   struct fake_mallinfo res;
98   REAL(memset)(&res, 0, sizeof(res));
99   return res;
100 }
101 
INTERCEPTOR(int,mallopt,int cmd,int value)102 INTERCEPTOR(int, mallopt, int cmd, int value) {
103   return -1;
104 }
105 
INTERCEPTOR(int,posix_memalign,void ** memptr,uptr alignment,uptr size)106 INTERCEPTOR(int, posix_memalign, void **memptr, uptr alignment, uptr size) {
107   GET_STACK_TRACE_MALLOC;
108   // Printf("posix_memalign: %zx %zu\n", alignment, size);
109   return asan_posix_memalign(memptr, alignment, size, &stack);
110 }
111 
INTERCEPTOR(void *,valloc,uptr size)112 INTERCEPTOR(void*, valloc, uptr size) {
113   GET_STACK_TRACE_MALLOC;
114   return asan_valloc(size, &stack);
115 }
116 
INTERCEPTOR(void *,pvalloc,uptr size)117 INTERCEPTOR(void*, pvalloc, uptr size) {
118   GET_STACK_TRACE_MALLOC;
119   return asan_pvalloc(size, &stack);
120 }
121 
INTERCEPTOR(void,malloc_stats,void)122 INTERCEPTOR(void, malloc_stats, void) {
123   __asan_print_accumulated_stats();
124 }
125 
126 #if SANITIZER_ANDROID
127 // Format of __libc_malloc_dispatch has changed in Android L.
128 // While we are moving towards a solution that does not depend on bionic
129 // internals, here is something to support both K* and L releases.
130 struct MallocDebugK {
131   void *(*malloc)(uptr bytes);
132   void (*free)(void *mem);
133   void *(*calloc)(uptr n_elements, uptr elem_size);
134   void *(*realloc)(void *oldMem, uptr bytes);
135   void *(*memalign)(uptr alignment, uptr bytes);
136   uptr (*malloc_usable_size)(void *mem);
137 };
138 
139 struct MallocDebugL {
140   void *(*calloc)(uptr n_elements, uptr elem_size);
141   void (*free)(void *mem);
142   fake_mallinfo (*mallinfo)(void);
143   void *(*malloc)(uptr bytes);
144   uptr (*malloc_usable_size)(void *mem);
145   void *(*memalign)(uptr alignment, uptr bytes);
146   int (*posix_memalign)(void **memptr, uptr alignment, uptr size);
147   void* (*pvalloc)(uptr size);
148   void *(*realloc)(void *oldMem, uptr bytes);
149   void* (*valloc)(uptr size);
150 };
151 
152 ALIGNED(32) const MallocDebugK asan_malloc_dispatch_k = {
153     WRAP(malloc),  WRAP(free),     WRAP(calloc),
154     WRAP(realloc), WRAP(memalign), WRAP(malloc_usable_size)};
155 
156 ALIGNED(32) const MallocDebugL asan_malloc_dispatch_l = {
157     WRAP(calloc),         WRAP(free),               WRAP(mallinfo),
158     WRAP(malloc),         WRAP(malloc_usable_size), WRAP(memalign),
159     WRAP(posix_memalign), WRAP(pvalloc),            WRAP(realloc),
160     WRAP(valloc)};
161 
162 namespace __asan {
ReplaceSystemMalloc()163 void ReplaceSystemMalloc() {
164   void **__libc_malloc_dispatch_p =
165       (void **)AsanDlSymNext("__libc_malloc_dispatch");
166   if (__libc_malloc_dispatch_p) {
167     // Decide on K vs L dispatch format by the presence of
168     // __libc_malloc_default_dispatch export in libc.
169     void *default_dispatch_p = AsanDlSymNext("__libc_malloc_default_dispatch");
170     if (default_dispatch_p)
171       *__libc_malloc_dispatch_p = (void *)&asan_malloc_dispatch_k;
172     else
173       *__libc_malloc_dispatch_p = (void *)&asan_malloc_dispatch_l;
174   }
175 }
176 }  // namespace __asan
177 
178 #else  // SANITIZER_ANDROID
179 
180 namespace __asan {
ReplaceSystemMalloc()181 void ReplaceSystemMalloc() {
182 }
183 }  // namespace __asan
184 #endif  // SANITIZER_ANDROID
185 
186 #endif  // SANITIZER_FREEBSD || SANITIZER_LINUX
187