[PATCH v1 1/3] String: Add additional overflow tests for strnlen, memchr, and strncat

[Noah Goldstein <goldstein.w.n@gmail.com>]

This commit adds tests for a bug in the wide char variant of the
functions where the implementation may assume that maxlen for wcsnlen
or n for wmemchr/strncat will not overflow when multiplied by
sizeof(wchar_t).

These tests show the following implementations failing on x86_64:

wcsnlen-sse4_1
wcsnlen-avx2

wmemchr-sse2
wmemchr-avx2

strncat would fail as well if it where on a system that prefered
either of the wcsnlen implementations that failed as it relies on
wcsnlen.

Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
---
 string/test-memchr.c  | 39 ++++++++++++++++++++++++---
 string/test-strncat.c | 61 +++++++++++++++++++++++++++++++++++++++++++
 string/test-strnlen.c | 33 +++++++++++++++++++++++
 3 files changed, 130 insertions(+), 3 deletions(-)

diff --git a/string/test-memchr.c b/string/test-memchr.c
index 665edc32af..ce964284aa 100644
--- a/string/test-memchr.c
+++ b/string/test-memchr.c
@@ -65,8 +65,8 @@ do_one_test (impl_t *impl, const CHAR *s, int c, size_t n, CHAR *exp_res)
   CHAR *res = CALL (impl, s, c, n);
   if (res != exp_res)
     {
-      error (0, 0, "Wrong result in function %s %p %p", impl->name,
-	     res, exp_res);
+      error (0, 0, "Wrong result in function %s (%p, %d, %zu) -> %p != %p",
+             impl->name, s, c, n, res, exp_res);
       ret = 1;
       return;
     }
@@ -91,7 +91,7 @@ do_test (size_t align, size_t pos, size_t len, size_t n, int seek_char)
     }
   buf[align + len] = 0;
 
-  if (pos < len)
+  if (pos < MIN(n, len))
     {
       buf[align + pos] = seek_char;
       buf[align + len] = -seek_char;
@@ -107,6 +107,38 @@ do_test (size_t align, size_t pos, size_t len, size_t n, int seek_char)
     do_one_test (impl, (CHAR *) (buf + align), seek_char, n, result);
 }
 
+static void
+do_overflow_tests (void)
+{
+  size_t i, j, len;
+  const size_t one = 1;
+  uintptr_t buf_addr = (uintptr_t) buf1;
+
+  for (i = 0; i < 750; ++i)
+    {
+        do_test (0, i, 751, SIZE_MAX - i, BIG_CHAR);
+        do_test (0, i, 751, i - buf_addr, BIG_CHAR);
+        do_test (0, i, 751, -buf_addr - i, BIG_CHAR);
+        do_test (0, i, 751, SIZE_MAX - buf_addr - i, BIG_CHAR);
+        do_test (0, i, 751, SIZE_MAX - buf_addr + i, BIG_CHAR);
+
+      len = 0;
+      for (j = 8 * sizeof(size_t) - 1; j ; --j)
+        {
+          len |= one << j;
+          do_test (0, i, 751, len - i, BIG_CHAR);
+          do_test (0, i, 751, len + i, BIG_CHAR);
+          do_test (0, i, 751, len - buf_addr - i, BIG_CHAR);
+          do_test (0, i, 751, len - buf_addr + i, BIG_CHAR);
+
+          do_test (0, i, 751, ~len - i, BIG_CHAR);
+          do_test (0, i, 751, ~len + i, BIG_CHAR);
+          do_test (0, i, 751, ~len - buf_addr - i, BIG_CHAR);
+          do_test (0, i, 751, ~len - buf_addr + i, BIG_CHAR);
+        }
+    }
+}
+
 static void
 do_random_tests (void)
 {
@@ -221,6 +253,7 @@ test_main (void)
     do_test (page_size / 2 - i, i, i, 1, 0x9B);
 
   do_random_tests ();
+  do_overflow_tests ();
   return ret;
 }
 
diff --git a/string/test-strncat.c b/string/test-strncat.c
index 2ef917b820..0ab7541d4e 100644
--- a/string/test-strncat.c
+++ b/string/test-strncat.c
@@ -134,6 +134,66 @@ do_test (size_t align1, size_t align2, size_t len1, size_t len2,
     }
 }
 
+static void
+do_overflow_tests (void)
+{
+  size_t i, j, len;
+  const size_t one = 1;
+  CHAR *s1, *s2;
+  uintptr_t s1_addr;
+  s1 = (CHAR *) buf1;
+  s2 = (CHAR *) buf2;
+  s1_addr = (uintptr_t)s1;
+ for (j = 0; j < 200; ++j)
+      s2[j] = 32 + 23 * j % (BIG_CHAR - 32);
+ s2[200] = 0;
+  for (i = 0; i < 750; ++i) {
+    for (j = 0; j < i; ++j)
+      s1[j] = 32 + 23 * j % (BIG_CHAR - 32);
+    s1[i] = '\0';
+
+       FOR_EACH_IMPL (impl, 0)
+    {
+      s2[0] = '\0';
+      do_one_test (impl, s2, s1, SIZE_MAX - i);
+      s2[0] = '\0';
+      do_one_test (impl, s2, s1, i - s1_addr);
+      s2[0] = '\0';
+      do_one_test (impl, s2, s1, -s1_addr - i);
+      s2[0] = '\0';
+      do_one_test (impl, s2, s1, SIZE_MAX - s1_addr - i);
+      s2[0] = '\0';
+      do_one_test (impl, s2, s1, SIZE_MAX - s1_addr + i);
+    }
+
+    len = 0;
+    for (j = 8 * sizeof(size_t) - 1; j ; --j)
+      {
+        len |= one << j;
+        FOR_EACH_IMPL (impl, 0)
+          {
+            s2[0] = '\0';
+            do_one_test (impl, s2, s1, len - i);
+            s2[0] = '\0';
+            do_one_test (impl, s2, s1, len + i);
+            s2[0] = '\0';
+            do_one_test (impl, s2, s1, len - s1_addr - i);
+            s2[0] = '\0';
+            do_one_test (impl, s2, s1, len - s1_addr + i);
+
+            s2[0] = '\0';
+            do_one_test (impl, s2, s1, ~len - i);
+            s2[0] = '\0';
+            do_one_test (impl, s2, s1, ~len + i);
+            s2[0] = '\0';
+            do_one_test (impl, s2, s1, ~len - s1_addr - i);
+            s2[0] = '\0';
+            do_one_test (impl, s2, s1, ~len - s1_addr + i);
+          }
+      }
+  }
+}
+
 static void
 do_random_tests (void)
 {
@@ -316,6 +376,7 @@ test_main (void)
     }
 
   do_random_tests ();
+  do_overflow_tests ();
   return ret;
 }
 
diff --git a/string/test-strnlen.c b/string/test-strnlen.c
index 920f58e97b..f53e09263f 100644
--- a/string/test-strnlen.c
+++ b/string/test-strnlen.c
@@ -89,6 +89,38 @@ do_test (size_t align, size_t len, size_t maxlen, int max_char)
     do_one_test (impl, (CHAR *) (buf + align), maxlen, MIN (len, maxlen));
 }
 
+static void
+do_overflow_tests (void)
+{
+  size_t i, j, len;
+  const size_t one = 1;
+  uintptr_t buf_addr = (uintptr_t) buf1;
+
+  for (i = 0; i < 750; ++i)
+    {
+      do_test (0, i, SIZE_MAX - i, BIG_CHAR);
+      do_test (0, i, i - buf_addr, BIG_CHAR);
+      do_test (0, i, -buf_addr - i, BIG_CHAR);
+      do_test (0, i, SIZE_MAX - buf_addr - i, BIG_CHAR);
+      do_test (0, i, SIZE_MAX - buf_addr + i, BIG_CHAR);
+
+      len = 0;
+      for (j = 8 * sizeof(size_t) - 1; j ; --j)
+        {
+          len |= one << j;
+          do_test (0, i, len - i, BIG_CHAR);
+          do_test (0, i, len + i, BIG_CHAR);
+          do_test (0, i, len - buf_addr - i, BIG_CHAR);
+          do_test (0, i, len - buf_addr + i, BIG_CHAR);
+
+          do_test (0, i, ~len - i, BIG_CHAR);
+          do_test (0, i, ~len + i, BIG_CHAR);
+          do_test (0, i, ~len - buf_addr - i, BIG_CHAR);
+          do_test (0, i, ~len - buf_addr + i, BIG_CHAR);
+        }
+    }
+}
+
 static void
 do_random_tests (void)
 {
@@ -283,6 +315,7 @@ test_main (void)
   do_random_tests ();
   do_page_tests ();
   do_page_2_tests ();
+  do_overflow_tests ();
   return ret;
 }
 
-- 
2.25.1