Bug 20292 - Simplify and test _dl_addr_inside_object

The function _dl_addr_inside_object is simplified by removing
the conditional 'reladdr - l->l_phdr[n].p_vaddr >= 0' which is
always true. The function is refactored into it's own object file
and a unit test added to verify the correct behaviour of the
function.

1 files changed, 223 insertions, 0 deletions

diff --git a/elf/tst-_dl_addr_inside_object.c b/elf/tst-_dl_addr_inside_object.c
new file mode 100644
index 0000000000..d1e45815c8
--- /dev/null
+++ b/elf/tst-_dl_addr_inside_object.c
@@ -0,0 +1,223 @@
+/* Unit test for _dl_addr_inside_object.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <link.h>
+#include <elf.h>
+#include <libc-symbols.h>
+
+extern int internal_function _dl_addr_inside_object (struct link_map *l,
+						     const ElfW(Addr) addr);
+
+static int
+do_test (void)
+{
+  int ret, err = 0;
+  ElfW(Addr) addr;
+  struct link_map map;
+  ElfW(Phdr) header;
+  map.l_phdr = &header;
+  map.l_phnum = 1;
+  map.l_addr = 0x0;
+  /* Segment spans 0x2000 -> 0x4000.  */
+  header.p_vaddr = 0x2000;
+  header.p_memsz = 0x2000;
+  header.p_type = PT_LOAD;
+  /* Address is above the segment e.g. > 0x4000.  */
+  addr = 0x5000;
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("PASS: Above: Address is detected as outside the segment.\n");
+	break;
+      case 1:
+        printf ("FAIL: Above: Address is detected as inside the segment.\n");
+	err++;
+	break;
+      default:
+	printf ("FAIL: Above: Invalid return value.\n");
+	exit (1);
+    }
+  /* Address is inside the segment e.g. 0x2000 < addr < 0x4000.  */
+  addr = 0x3000;
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("FAIL: Inside: Address is detected as outside the segment.\n");
+	err++;
+	break;
+      case 1:
+        printf ("PASS: Inside: Address is detected as inside the segment.\n");
+	break;
+      default:
+	printf ("FAIL: Inside: Invalid return value.\n");
+	exit (1);
+    }
+  /* Address is below the segment e.g. < 0x2000.  */
+  addr = 0x1000;
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("PASS: Below: Address is detected as outside the segment.\n");
+	break;
+      case 1:
+        printf ("FAIL: Below: Address is detected as inside the segment.\n");
+	err++;
+	break;
+      default:
+	printf ("FAIL: Below: Invalid return value.\n");
+	exit (1);
+    }
+  /* Address is in the segment and addr == p_vaddr.  */
+  addr = 0x2000;
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("FAIL: At p_vaddr: Address is detected as outside the segment.\n");
+	err++;
+	break;
+      case 1:
+        printf ("PASS: At p_vaddr: Address is detected as inside the segment.\n");
+	break;
+      default:
+	printf ("FAIL: At p_vaddr: Invalid return value.\n");
+	exit (1);
+    }
+  /* Address is in the segment and addr == p_vaddr + p_memsz - 1.  */
+  addr = 0x2000 + 0x2000 - 0x1;
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("FAIL: At p_memsz-1: Address is detected as outside the segment.\n");
+	err++;
+	break;
+      case 1:
+        printf ("PASS: At p_memsz-1: Address is detected as inside the segment.\n");
+	break;
+      default:
+	printf ("FAIL: At p_memsz-1: Invalid return value.\n");
+	exit (1);
+    }
+  /* Address is outside the segment and addr == p_vaddr + p_memsz.  */
+  addr = 0x2000 + 0x2000;
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("PASS: At p_memsz: Address is detected as outside the segment.\n");
+	break;
+      case 1:
+        printf ("FAIL: At p_memsz: Address is detected as inside the segment.\n");
+	err++;
+	break;
+      default:
+	printf ("FAIL: At p_memsz: Invalid return value.\n");
+	exit (1);
+    }
+  /* Address is outside the segment and p_vaddr at maximum address.  */
+  addr = 0x0 - 0x2;
+  header.p_vaddr = 0x0 - 0x1;
+  header.p_memsz = 0x1;
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("PASS: At max: Address is detected as outside the segment.\n");
+	break;
+      case 1:
+        printf ("FAIL: At max: Address is detected as inside the segment.\n");
+	err++;
+	break;
+      default:
+	printf ("FAIL: At max: Invalid return value.\n");
+	exit (1);
+    }
+  /* Address is outside the segment and p_vaddr at minimum address.  */
+  addr = 0x1;
+  header.p_vaddr = 0x0;
+  header.p_memsz = 0x1;
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("PASS: At min: Address is detected as outside the segment.\n");
+	break;
+      case 1:
+        printf ("FAIL: At min: Address is detected as inside the segment.\n");
+	err++;
+	break;
+      default:
+	printf ("FAIL: At min: Invalid return value.\n");
+	exit (1);
+    }
+  /* Address is always inside the segment with p_memsz at max.  */
+  addr = 0x0;
+  header.p_vaddr = 0x0;
+  header.p_memsz = 0x0 - 0x1;
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("FAIL: At maxmem: Address is detected as outside the segment.\n");
+	err++;
+	break;
+      case 1:
+        printf ("PASS: At maxmem: Address is detected as inside the segment.\n");
+	break;
+      default:
+	printf ("FAIL: At maxmem: Invalid return value.\n");
+	exit (1);
+    }
+  /* Attempt to wrap addr into the segment.
+     Pick a load address in the middle of the address space.
+     Place the test address at 0x0 so it wraps to the middle again.  */
+  map.l_addr = 0x0 - 0x1;
+  map.l_addr = map.l_addr / 2;
+  addr = 0;
+  /* Setup a segment covering 1/2 the address space.  */
+  header.p_vaddr = 0x0;
+  header.p_memsz = 0x0 - 0x1 - map.l_addr;
+  /* No matter where you place addr everything is shifted modulo l_addr
+     and even with this underflow you're always 1 byte away from being
+     in the range.  */
+  ret = _dl_addr_inside_object (&map, addr);
+  switch (ret)
+    {
+      case 0:
+	printf ("PASS: Underflow: Address is detected as outside the segment.\n");
+	break;
+      case 1:
+	printf ("FAIL: Underflow: Address is detected as inside the segment.\n");
+	err++;
+	break;
+      default:
+	printf ("FAIL: Underflow: Invalid return value.\n");
+	exit (1);
+    }
+
+  return err;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"