1 #include "sanitizer_common/sanitizer_atomic.h"
2
3 #include <stdlib.h>
4 #include <stdint.h>
5 #include <string.h>
6 #include <unistd.h>
7
8 #ifdef KERNEL_USE
9 extern "C" void ubsan_message(const char *msg);
message(const char * msg)10 static void message(const char *msg) { ubsan_message(msg); }
11 #else
message(const char * msg)12 static void message(const char *msg) {
13 (void)write(2, msg, strlen(msg));
14 }
15 #endif
16
17 static const int kMaxCallerPcs = 20;
18 static __sanitizer::atomic_uintptr_t caller_pcs[kMaxCallerPcs];
19 // Number of elements in caller_pcs. A special value of kMaxCallerPcs + 1 means
20 // that "too many errors" has already been reported.
21 static __sanitizer::atomic_uint32_t caller_pcs_sz;
22
report_this_error(uintptr_t caller)23 __attribute__((noinline)) static bool report_this_error(uintptr_t caller) {
24 if (caller == 0)
25 return false;
26 while (true) {
27 unsigned sz = __sanitizer::atomic_load_relaxed(&caller_pcs_sz);
28 if (sz > kMaxCallerPcs) return false; // early exit
29 // when sz==kMaxCallerPcs print "too many errors", but only when cmpxchg
30 // succeeds in order to not print it multiple times.
31 if (sz > 0 && sz < kMaxCallerPcs) {
32 uintptr_t p;
33 for (unsigned i = 0; i < sz; ++i) {
34 p = __sanitizer::atomic_load_relaxed(&caller_pcs[i]);
35 if (p == 0) break; // Concurrent update.
36 if (p == caller) return false;
37 }
38 if (p == 0) continue; // FIXME: yield?
39 }
40
41 if (!__sanitizer::atomic_compare_exchange_strong(
42 &caller_pcs_sz, &sz, sz + 1, __sanitizer::memory_order_seq_cst))
43 continue; // Concurrent update! Try again from the start.
44
45 if (sz == kMaxCallerPcs) {
46 message("ubsan: too many errors\n");
47 return false;
48 }
49 __sanitizer::atomic_store_relaxed(&caller_pcs[sz], caller);
50 return true;
51 }
52 }
53
decorate_msg(char * buf,uintptr_t caller)54 __attribute__((noinline)) static void decorate_msg(char *buf,
55 uintptr_t caller) {
56 // print the address by nibbles
57 for (unsigned shift = sizeof(uintptr_t) * 8; shift;) {
58 shift -= 4;
59 unsigned nibble = (caller >> shift) & 0xf;
60 *(buf++) = nibble < 10 ? nibble + '0' : nibble - 10 + 'a';
61 }
62 // finish the message
63 buf[0] = '\n';
64 buf[1] = '\0';
65 }
66
67 #if defined(__ANDROID__)
68 extern "C" __attribute__((weak)) void android_set_abort_message(const char *);
abort_with_message(const char * msg)69 static void abort_with_message(const char *msg) {
70 if (&android_set_abort_message) android_set_abort_message(msg);
71 abort();
72 }
73 #else
abort_with_message(const char *)74 static void abort_with_message(const char *) { abort(); }
75 #endif
76
77 #if SANITIZER_DEBUG
78 namespace __sanitizer {
79 // The DCHECK macro needs this symbol to be defined.
CheckFailed(const char * file,int,const char * cond,u64,u64)80 void NORETURN CheckFailed(const char *file, int, const char *cond, u64, u64) {
81 message("Sanitizer CHECK failed: ");
82 message(file);
83 message(":?? : "); // FIXME: Show line number.
84 message(cond);
85 abort();
86 }
87 } // namespace __sanitizer
88 #endif
89
90 #define INTERFACE extern "C" __attribute__((visibility("default")))
91
92 // How many chars we need to reserve to print an address.
93 constexpr unsigned kAddrBuf = SANITIZER_WORDSIZE / 4;
94 #define MSG_TMPL(msg) "ubsan: " msg " by 0x"
95 #define MSG_TMPL_END(buf, msg) (buf + sizeof(MSG_TMPL(msg)) - 1)
96 // Reserve an additional byte for '\n'.
97 #define MSG_BUF_LEN(msg) (sizeof(MSG_TMPL(msg)) + kAddrBuf + 1)
98
99 #define HANDLER_RECOVER(name, msg) \
100 INTERFACE void __ubsan_handle_##name##_minimal() { \
101 uintptr_t caller = GET_CALLER_PC(); \
102 if (!report_this_error(caller)) return; \
103 char msg_buf[MSG_BUF_LEN(msg)] = MSG_TMPL(msg); \
104 decorate_msg(MSG_TMPL_END(msg_buf, msg), caller); \
105 message(msg_buf); \
106 }
107
108 #define HANDLER_NORECOVER(name, msg) \
109 INTERFACE void __ubsan_handle_##name##_minimal_abort() { \
110 char msg_buf[MSG_BUF_LEN(msg)] = MSG_TMPL(msg); \
111 decorate_msg(MSG_TMPL_END(msg_buf, msg), GET_CALLER_PC()); \
112 message(msg_buf); \
113 abort_with_message(msg_buf); \
114 }
115
116 #define HANDLER(name, msg) \
117 HANDLER_RECOVER(name, msg) \
118 HANDLER_NORECOVER(name, msg)
119
120 HANDLER(type_mismatch, "type-mismatch")
121 HANDLER(alignment_assumption, "alignment-assumption")
122 HANDLER(add_overflow, "add-overflow")
123 HANDLER(sub_overflow, "sub-overflow")
124 HANDLER(mul_overflow, "mul-overflow")
125 HANDLER(negate_overflow, "negate-overflow")
126 HANDLER(divrem_overflow, "divrem-overflow")
127 HANDLER(shift_out_of_bounds, "shift-out-of-bounds")
128 HANDLER(out_of_bounds, "out-of-bounds")
129 HANDLER_RECOVER(builtin_unreachable, "builtin-unreachable")
130 HANDLER_RECOVER(missing_return, "missing-return")
131 HANDLER(vla_bound_not_positive, "vla-bound-not-positive")
132 HANDLER(float_cast_overflow, "float-cast-overflow")
133 HANDLER(load_invalid_value, "load-invalid-value")
134 HANDLER(invalid_builtin, "invalid-builtin")
135 HANDLER(invalid_objc_cast, "invalid-objc-cast")
136 HANDLER(function_type_mismatch, "function-type-mismatch")
137 HANDLER(implicit_conversion, "implicit-conversion")
138 HANDLER(nonnull_arg, "nonnull-arg")
139 HANDLER(nonnull_return, "nonnull-return")
140 HANDLER(nullability_arg, "nullability-arg")
141 HANDLER(nullability_return, "nullability-return")
142 HANDLER(pointer_overflow, "pointer-overflow")
143 HANDLER(cfi_check_fail, "cfi-check-fail")
144