compiler-rt/include/sanitizer/dfsan_interface.h

   1 //===-- dfsan_interface.h -------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of DataFlowSanitizer.
  10 //
  11 // Public interface header.
  12 //===----------------------------------------------------------------------===//
  13 #ifndef DFSAN_INTERFACE_H
  14 #define DFSAN_INTERFACE_H
  15
  16 #include <stddef.h>
  17 #include <stdint.h>
  18 #include <sanitizer/common_interface_defs.h>
  19
  20 #ifdef __cplusplus
  21 extern "C" {
  22 #endif
  23
  24 typedef uint8_t dfsan_label;
  25 typedef uint32_t dfsan_origin;
  26
  27 /// Signature of the callback argument to dfsan_set_write_callback().
  28 typedef void (*dfsan_write_callback_t)(int fd, const void *buf, size_t count);
  29
  30 /// Signature of the callback argument to dfsan_set_conditional_callback().
  31 typedef void (*dfsan_conditional_callback_t)(dfsan_label label,
  32                                              dfsan_origin origin);
  33
  34 /// Signature of the callback argument to dfsan_set_reaches_function_callback().
  35 /// The description is intended to hold the name of the variable.
  36 typedef void (*dfsan_reaches_function_callback_t)(dfsan_label label,
  37                                                   dfsan_origin origin,
  38                                                   const char *file,
  39                                                   unsigned int line,
  40                                                   const char *function);
  41
  42 /// Computes the union of \c l1 and \c l2, resulting in a union label.
  43 dfsan_label dfsan_union(dfsan_label l1, dfsan_label l2);
  44
  45 /// Sets the label for each address in [addr,addr+size) to \c label.
  46 void dfsan_set_label(dfsan_label label, void *addr, size_t size);
  47
  48 /// Sets the label for each address in [addr,addr+size) to the union of the
  49 /// current label for that address and \c label.
  50 void dfsan_add_label(dfsan_label label, void *addr, size_t size);
  51
  52 /// Retrieves the label associated with the given data.
  53 ///
  54 /// The type of 'data' is arbitrary.  The function accepts a value of any type,
  55 /// which can be truncated or extended (implicitly or explicitly) as necessary.
  56 /// The truncation/extension operations will preserve the label of the original
  57 /// value.
  58 dfsan_label dfsan_get_label(long data);
  59
  60 /// Retrieves the immediate origin associated with the given data. The returned
  61 /// origin may point to another origin.
  62 ///
  63 /// The type of 'data' is arbitrary.
  64 dfsan_origin dfsan_get_origin(long data);
  65
  66 /// Retrieves the label associated with the data at the given address.
  67 dfsan_label dfsan_read_label(const void *addr, size_t size);
  68
  69 /// Return the origin associated with the first taint byte in the size bytes
  70 /// from the address addr.
  71 dfsan_origin dfsan_read_origin_of_first_taint(const void *addr, size_t size);
  72
  73 /// Returns whether the given label label contains the label elem.
  74 int dfsan_has_label(dfsan_label label, dfsan_label elem);
  75
  76 /// Flushes the DFSan shadow, i.e. forgets about all labels currently associated
  77 /// with the application memory.  Use this call to start over the taint tracking
  78 /// within the same process.
  79 ///
  80 /// Note: If another thread is working with tainted data during the flush, that
  81 /// taint could still be written to shadow after the flush.
  82 void dfsan_flush(void);
  83
  84 /// Sets a callback to be invoked on calls to write().  The callback is invoked
  85 /// before the write is done.  The write is not guaranteed to succeed when the
  86 /// callback executes.  Pass in NULL to remove any callback.
  87 void dfsan_set_write_callback(dfsan_write_callback_t labeled_write_callback);
  88
  89 /// Sets a callback to be invoked on any conditional expressions which have a
  90 /// taint label set. This can be used to find where tainted data influences
  91 /// the behavior of the program.
  92 /// These callbacks will only be added when -dfsan-conditional-callbacks=true.
  93 void dfsan_set_conditional_callback(dfsan_conditional_callback_t callback);
  94
  95 /// Conditional expressions occur during signal handlers.
  96 /// Making callbacks that handle signals well is tricky, so when
  97 /// -dfsan-conditional-callbacks=true, conditional expressions used in signal
  98 /// handlers will add the labels they see into a global (bitwise-or together).
  99 /// This function returns all label bits seen in signal handler conditions.
 100 dfsan_label dfsan_get_labels_in_signal_conditional();
 101
 102 /// Sets a callback to be invoked when tainted data reaches a function.
 103 /// This could occur at function entry, or at a load instruction.
 104 /// These callbacks will only be added if -dfsan-reaches-function-callbacks=1.
 105 void dfsan_set_reaches_function_callback(
 106     dfsan_reaches_function_callback_t callback);
 107
 108 /// Making callbacks that handle signals well is tricky, so when
 109 /// -dfsan-reaches-function-callbacks=true, functions reached in signal
 110 /// handlers will add the labels they see into a global (bitwise-or together).
 111 /// This function returns all label bits seen during signal handlers.
 112 dfsan_label dfsan_get_labels_in_signal_reaches_function();
 113
 114 /// Interceptor hooks.
 115 /// Whenever a dfsan's custom function is called the corresponding
 116 /// hook is called it non-zero. The hooks should be defined by the user.
 117 /// The primary use case is taint-guided fuzzing, where the fuzzer
 118 /// needs to see the parameters of the function and the labels.
 119 /// FIXME: implement more hooks.
 120 void dfsan_weak_hook_memcmp(void *caller_pc, const void *s1, const void *s2,
 121                             size_t n, dfsan_label s1_label,
 122                             dfsan_label s2_label, dfsan_label n_label);
 123 void dfsan_weak_hook_strncmp(void *caller_pc, const char *s1, const char *s2,
 124                              size_t n, dfsan_label s1_label,
 125                              dfsan_label s2_label, dfsan_label n_label);
 126
 127 /// Prints the origin trace of the label at the address addr to stderr. It also
 128 /// prints description at the beginning of the trace. If origin tracking is not
 129 /// on, or the address is not labeled, it prints nothing.
 130 void dfsan_print_origin_trace(const void *addr, const char *description);
 131 /// As above, but use an origin id from dfsan_get_origin() instead of address.
 132 /// Does not include header line with taint label and address information.
 133 void dfsan_print_origin_id_trace(dfsan_origin origin);
 134
 135 /// Prints the origin trace of the label at the address \p addr to a
 136 /// pre-allocated output buffer. If origin tracking is not on, or the address is
 137 /// not labeled, it prints nothing.
 138 ///
 139 /// Typical usage:
 140 /// \code
 141 ///   char kDescription[] = "...";
 142 ///   char buf[1024];
 143 ///   dfsan_sprint_origin_trace(&tainted_var, kDescription, buf, sizeof(buf));
 144 /// \endcode
 145 ///
 146 /// Typical usage that handles truncation:
 147 /// \code
 148 ///   char buf[1024];
 149 ///   int len = dfsan_sprint_origin_trace(&var, nullptr, buf, sizeof(buf));
 150 ///
 151 ///   if (len < sizeof(buf)) {
 152 ///     ProcessOriginTrace(buf);
 153 ///   } else {
 154 ///     char *tmpbuf = new char[len + 1];
 155 ///     dfsan_sprint_origin_trace(&var, nullptr, tmpbuf, len + 1);
 156 ///     ProcessOriginTrace(tmpbuf);
 157 ///     delete[] tmpbuf;
 158 ///   }
 159 /// \endcode
 160 ///
 161 /// \param addr The tainted memory address whose origin we are printing.
 162 /// \param description A description printed at the beginning of the trace.
 163 /// \param [out] out_buf The output buffer to write the results to.
 164 /// \param out_buf_size The size of \p out_buf.
 165 ///
 166 /// \returns The number of symbols that should have been written to \p out_buf
 167 /// (not including trailing null byte '\0'). Thus, the string is truncated iff
 168 /// return value is not less than \p out_buf_size.
 169 size_t dfsan_sprint_origin_trace(const void *addr, const char *description,
 170                                  char *out_buf, size_t out_buf_size);
 171 /// As above, but use an origin id from dfsan_get_origin() instead of address.
 172 /// Does not include header line with taint label and address information.
 173 size_t dfsan_sprint_origin_id_trace(dfsan_origin origin, char *out_buf,
 174                                     size_t out_buf_size);
 175
 176 /// Prints the stack trace leading to this call to a pre-allocated output
 177 /// buffer.
 178 ///
 179 /// For usage examples, see dfsan_sprint_origin_trace.
 180 ///
 181 /// \param [out] out_buf The output buffer to write the results to.
 182 /// \param out_buf_size The size of \p out_buf.
 183 ///
 184 /// \returns The number of symbols that should have been written to \p out_buf
 185 /// (not including trailing null byte '\0'). Thus, the string is truncated iff
 186 /// return value is not less than \p out_buf_size.
 187 size_t dfsan_sprint_stack_trace(char *out_buf, size_t out_buf_size);
 188
 189 /// Retrieves the very first origin associated with the data at the given
 190 /// address.
 191 dfsan_origin dfsan_get_init_origin(const void *addr);
 192
 193 /// Returns the value of -dfsan-track-origins.
 194 /// * 0: do not track origins.
 195 /// * 1: track origins at memory store operations.
 196 /// * 2: track origins at memory load and store operations.
 197 int dfsan_get_track_origins(void);
 198 #ifdef __cplusplus
 199 }  // extern "C"
 200
 201 template <typename T> void dfsan_set_label(dfsan_label label, T &data) {
 202   dfsan_set_label(label, (void *)&data, sizeof(T));
 203 }
 204
 205 #endif
 206
 207 #endif  // DFSAN_INTERFACE_H