[dfsan] Initial set of custom functions and interceptors for libc.

Differential Revision: http://llvm-reviews.chandlerc.com/D1397

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@188490 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 275 insertions, 0 deletions

diff --git a/lib/dfsan/dfsan_custom.cc b/lib/dfsan/dfsan_custom.cc
new file mode 100644
index 000000000..657c80f89
--- /dev/null
+++ b/lib/dfsan/dfsan_custom.cc
@@ -0,0 +1,275 @@
+//===-- dfsan.cc ----------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of DataFlowSanitizer.
+//
+// This file defines the custom functions listed in done_abilist.txt.
+//===----------------------------------------------------------------------===//
+#include "sanitizer/dfsan_interface.h"
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#include "sanitizer_common/sanitizer_linux.h"
+
+#include "dfsan/dfsan.h"
+
+#include <ctype.h>
+#include <dlfcn.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <unistd.h>
+
+using namespace __dfsan;
+
+extern "C" {
+
+SANITIZER_INTERFACE_ATTRIBUTE int
+__dfsw_stat(const char *path, struct stat *buf, dfsan_label path_label,
+            dfsan_label buf_label, dfsan_label *ret_label) {
+  int ret = stat(path, buf);
+  if (ret == 0)
+    dfsan_set_label(0, buf, sizeof(struct stat));
+  *ret_label = 0;
+  return ret;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_fstat(int fd, struct stat *buf,
+                                               dfsan_label fd_label,
+                                               dfsan_label buf_label,
+                                               dfsan_label *ret_label) {
+  int ret = fstat(fd, buf);
+  if (ret == 0)
+    dfsan_set_label(0, buf, sizeof(struct stat));
+  *ret_label = 0;
+  return ret;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strchr(const char *s, int c,
+                                                  dfsan_label s_label,
+                                                  dfsan_label c_label,
+                                                  dfsan_label *ret_label) {
+  for (size_t i = 0;; ++i) {
+    if (s[i] == c || s[i] == 0) {
+      *ret_label = dfsan_union(dfsan_read_label(s, i+1), c_label);
+      return s[i] == 0 ? 0 : const_cast<char *>(s+i);
+    }
+  }
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_memcmp(const void *s1, const void *s2,
+                                                size_t n, dfsan_label s1_label,
+                                                dfsan_label s2_label,
+                                                dfsan_label n_label,
+                                                dfsan_label *ret_label) {
+  const char *cs1 = (const char *) s1, *cs2 = (const char *) s2;
+  for (size_t i = 0; i != n; ++i) {
+    if (cs1[i] != cs2[i]) {
+      *ret_label = dfsan_union(dfsan_read_label(cs1, i+1),
+                               dfsan_read_label(cs2, i+1));
+      return cs1[i] - cs2[i];
+    }
+  }
+  *ret_label = dfsan_union(dfsan_read_label(cs1, n),
+                           dfsan_read_label(cs2, n));
+  return 0;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strcmp(const char *s1, const char *s2,
+                                                dfsan_label s1_label,
+                                                dfsan_label s2_label,
+                                                dfsan_label *ret_label) {
+  for (size_t i = 0;; ++i) {
+    if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0) {
+      *ret_label = dfsan_union(dfsan_read_label(s1, i+1),
+                               dfsan_read_label(s2, i+1));
+      return s1[i] - s2[i];
+    }
+  }
+  return 0;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE int
+__dfsw_strcasecmp(const char *s1, const char *s2, dfsan_label s1_label,
+                  dfsan_label s2_label, dfsan_label *ret_label) {
+  for (size_t i = 0;; ++i) {
+    if (tolower(s1[i]) != tolower(s2[i]) || s1[i] == 0 || s2[i] == 0) {
+      *ret_label = dfsan_union(dfsan_read_label(s1, i+1),
+                               dfsan_read_label(s2, i+1));
+      return s1[i] - s2[i];
+    }
+  }
+  return 0;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strncmp(const char *s1, const char *s2,
+                                                 size_t n, dfsan_label s1_label,
+                                                 dfsan_label s2_label,
+                                                 dfsan_label n_label,
+                                                 dfsan_label *ret_label) {
+  if (n == 0) {
+    *ret_label = 0;
+    return 0;
+  }
+
+  for (size_t i = 0;; ++i) {
+    if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0 || i == n-1) {
+      *ret_label = dfsan_union(dfsan_read_label(s1, i+1),
+                               dfsan_read_label(s2, i+1));
+      return s1[i] - s2[i];
+    }
+  }
+  return 0;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE int
+__dfsw_strncasecmp(const char *s1, const char *s2, size_t n,
+                   dfsan_label s1_label, dfsan_label s2_label,
+                   dfsan_label n_label, dfsan_label *ret_label) {
+  if (n == 0) {
+    *ret_label = 0;
+    return 0;
+  }
+
+  for (size_t i = 0;; ++i) {
+    if (tolower(s1[i]) != tolower(s2[i]) || s1[i] == 0 || s2[i] == 0 ||
+        i == n - 1) {
+      *ret_label = dfsan_union(dfsan_read_label(s1, i+1),
+                               dfsan_read_label(s2, i+1));
+      return s1[i] - s2[i];
+    }
+  }
+  return 0;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE void *__dfsw_calloc(size_t nmemb, size_t size,
+                                                  dfsan_label nmemb_label,
+                                                  dfsan_label size_label,
+                                                  dfsan_label *ret_label) {
+  void *p = calloc(nmemb, size);
+  dfsan_set_label(0, p, nmemb * size);
+  *ret_label = 0;
+  return p;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE size_t
+__dfsw_strlen(const char *s, dfsan_label s_label, dfsan_label *ret_label) {
+  size_t ret = strlen(s);
+  *ret_label = dfsan_read_label(s, ret+1);
+  return ret;
+}
+
+
+static void *dfsan_memcpy(void *dest, const void *src, size_t n) {
+  dfsan_label *sdest = shadow_for(dest), *ssrc = shadow_for((void *)src);
+  internal_memcpy((void *)sdest, (void *)ssrc, n * sizeof(dfsan_label));
+  return internal_memcpy(dest, src, n);
+}
+
+static void dfsan_memset(void *s, int c, dfsan_label c_label, size_t n) {
+  internal_memset(s, c, n);
+  dfsan_set_label(c_label, s, n);
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void *__dfsw_memcpy(void *dest, const void *src, size_t n,
+                    dfsan_label dest_label, dfsan_label src_label,
+                    dfsan_label n_label, dfsan_label *ret_label) {
+  *ret_label = 0;
+  return dfsan_memcpy(dest, src, n);
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void *__dfsw_memset(void *s, int c, size_t n,
+                    dfsan_label s_label, dfsan_label c_label,
+                    dfsan_label n_label, dfsan_label *ret_label) {
+  dfsan_memset(s, c, c_label, n);
+  *ret_label = 0;
+  return s;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE char *
+__dfsw_strdup(const char *s, dfsan_label s_label, dfsan_label *ret_label) {
+  size_t len = strlen(s);
+  void *p = malloc(len+1);
+  dfsan_memcpy(p, s, len+1);
+  *ret_label = 0;
+  return static_cast<char *>(p);
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE char *
+__dfsw_strncpy(char *s1, const char *s2, size_t n, dfsan_label s1_label,
+               dfsan_label s2_label, dfsan_label n_label,
+               dfsan_label *ret_label) {
+  size_t len = strlen(s2);
+  if (len < n) {
+    dfsan_memcpy(s1, s2, len+1);
+    dfsan_memset(s1+len+1, 0, 0, n-len-1);
+  } else {
+    dfsan_memcpy(s1, s2, n);
+  }
+
+  *ret_label = 0;
+  return s1;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE ssize_t
+__dfsw_pread(int fd, void *buf, size_t count, off_t offset,
+             dfsan_label fd_label, dfsan_label buf_label,
+             dfsan_label count_label, dfsan_label offset_label,
+             dfsan_label *ret_label) {
+  ssize_t ret = pread(fd, buf, count, offset);
+  if (ret > 0)
+    dfsan_set_label(0, buf, ret);
+  *ret_label = 0;
+  return ret;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE ssize_t
+__dfsw_read(int fd, void *buf, size_t count,
+             dfsan_label fd_label, dfsan_label buf_label,
+             dfsan_label count_label,
+             dfsan_label *ret_label) {
+  ssize_t ret = read(fd, buf, count);
+  if (ret > 0)
+    dfsan_set_label(0, buf, ret);
+  *ret_label = 0;
+  return ret;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_clock_gettime(clockid_t clk_id,
+                                                       struct timespec *tp,
+                                                       dfsan_label clk_id_label,
+                                                       dfsan_label tp_label,
+                                                       dfsan_label *ret_label) {
+  int ret = clock_gettime(clk_id, tp);
+  if (ret == 0)
+    dfsan_set_label(0, tp, sizeof(struct timespec));
+  *ret_label = 0;
+  return ret;
+}
+
+static void unpoison(const void *ptr, uptr size) {
+  dfsan_set_label(0, const_cast<void *>(ptr), size);
+}
+
+// dlopen() ultimately calls mmap() down inside the loader, which generally
+// doesn't participate in dynamic symbol resolution.  Therefore we won't
+// intercept its calls to mmap, and we have to hook it here.
+SANITIZER_INTERFACE_ATTRIBUTE void *
+__dfsw_dlopen(const char *filename, int flag, dfsan_label filename_label,
+              dfsan_label flag_label, dfsan_label *ret_label) {
+  link_map *map = (link_map *)dlopen(filename, flag);
+  if (map)
+    ForEachMappedRegion(map, unpoison);
+  *ret_label = 0;
+  return (void *)map;
+}
+
+}