Fix unnecessary overallocation due to incomplete character

When incomplete characters are found at the end of a string the
code ran amok and allocated lots of memory.  Stricter limits
are now in place.

ChangeLog

@@ -1,5 +1,17 @@
 2011-05-28  Ulrich Drepper  <drepper@gmail.com>
 
+	[BZ #12811]
+	* posix/regex_internal.c (build_wcs_buffer): Don't signal we have to
+	grow the buffers more if it already has to be sufficient.
+	(build_wcs_upper_buffer): Likewise.
+	* posix/regexec.c (check_matching): Likewise.
+	(clean_state_log_if_needed): Likewise.
+	(extend_buffers): Don't enlarge buffers beyond size of the input
+	buffer.
+	Patches mostly by Emil Wojak <emil@wojak.eu>.
+	* posix/bug-regex32.c: New file.
+	* posix/Makefile (tests): Add bug-regex32.
+
 	* locale/findlocale.c (_nl_find_locale): Return right away if
 	_nl_explode_name failed.
 	* locale/programs/locarchive.c (add_locale_to_archive): Likewise.

NEWS

@@ -17,7 +17,7 @@ Version 2.14
   12545, 12551, 12582, 12583, 12587, 12597, 12601, 12611, 12625, 12626,
   12631, 12650, 12653, 12655, 12660, 12671, 12681, 12685, 12711, 12713,
   12714, 12717, 12723, 12724, 12734, 12738, 12746, 12766, 12775, 12777,
-  12782, 12788, 12792, 12795, 12813, 12814
+  12782, 12788, 12792, 12795, 12811, 12813, 12814
 
 * The RPC implementation in libc is obsoleted.  Old programs keep working
   but new programs cannot be linked with the routines in libc anymore.

posix/Makefile

@@ -82,7 +82,7 @@ tests		:= tstgetopt testfnm runtests runptests	     \
 		   bug-regex17 bug-regex18 bug-regex19 bug-regex20 \
 		   bug-regex21 bug-regex22 bug-regex23 bug-regex24 \
 		   bug-regex25 bug-regex26 bug-regex27 bug-regex28 \
-		   bug-regex29 bug-regex30 bug-regex31 \
+		   bug-regex29 bug-regex30 bug-regex31 bug-regex32 \
 		   tst-nice tst-nanosleep tst-regex2 \
 		   transbug tst-rxspencer tst-pcre tst-boost \
 		   bug-ga1 tst-vfork1 tst-vfork2 tst-vfork3 tst-waitid \

posix/bug-regex32.c

@@ -0,0 +1,36 @@
+// BZ 12811
+#include <regex.h>
+#include <stdio.h>
+#include <locale.h>
+
+static int
+do_test (void)
+{
+  char buf[1000];
+  regex_t preg;
+  if (setlocale (LC_CTYPE, "de_DE.UTF-8") == NULL)
+    {
+      puts ("setlocale failed");
+      return 1;
+    }
+
+  int e = regcomp (&preg, ".*ab", REG_ICASE);
+  if (e != 0)
+    {
+      regerror (e, &preg, buf, sizeof (buf));
+      printf ("regcomp = %d \"%s\"\n", e, buf);
+      return 1;
+    }
+
+  // Incomplete character at the end of the buffer
+  e = regexec (&preg, "aaaaaaaaaaaa\xc4", 0, NULL, 0);
+
+  regfree (&preg);
+  regerror (e, &preg, buf, sizeof (buf));
+  printf ("regexec = %d \"%s\"\n", e, buf);
+
+  return e != REG_NOMATCH;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"

posix/regex_internal.c

@@ -237,13 +237,8 @@ build_wcs_buffer (re_string_t *pstr)
       else
 	p = (const char *) pstr->raw_mbs + pstr->raw_mbs_idx + byte_idx;
       mbclen = __mbrtowc (&wc, p, remain_len, &pstr->cur_state);
-      if (BE (mbclen == (size_t) -2, 0))
-	{
-	  /* The buffer doesn't have enough space, finish to build.  */
-	  pstr->cur_state = prev_st;
-	  break;
-	}
-      else if (BE (mbclen == (size_t) -1 || mbclen == 0, 0))
+      if (BE (mbclen == (size_t) -1 || mbclen == 0
+	      || (mbclen == (size_t) -2 && pstr->bufs_len >= pstr->len), 0))
 	{
 	  /* We treat these cases as a singlebyte character.  */
 	  mbclen = 1;
@@ -252,6 +247,12 @@ build_wcs_buffer (re_string_t *pstr)
 	    wc = pstr->trans[wc];
 	  pstr->cur_state = prev_st;
 	}
+      else if (BE (mbclen == (size_t) -2, 0))
+	{
+	  /* The buffer doesn't have enough space, finish to build.  */
+	  pstr->cur_state = prev_st;
+	  break;
+	}
 
       /* Write wide character and padding.  */
       pstr->wcs[byte_idx++] = wc;
@@ -334,9 +335,11 @@ build_wcs_upper_buffer (re_string_t *pstr)
 	      for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
 		pstr->wcs[byte_idx++] = WEOF;
 	    }
-	  else if (mbclen == (size_t) -1 || mbclen == 0)
+	  else if (mbclen == (size_t) -1 || mbclen == 0
+		   || (mbclen == (size_t) -2 && pstr->bufs_len >= pstr->len))
 	    {
-	      /* It is an invalid character or '\0'.  Just use the byte.  */
+	      /* It is an invalid character, an incomplete character
+		 at the end of the string, or '\0'.  Just use the byte.  */
 	      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx];
 	      pstr->mbs[byte_idx] = ch;
 	      /* And also cast it to wide char.  */
@@ -449,7 +452,8 @@ build_wcs_upper_buffer (re_string_t *pstr)
 	    for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
 	      pstr->wcs[byte_idx++] = WEOF;
 	  }
-	else if (mbclen == (size_t) -1 || mbclen == 0)
+	else if (mbclen == (size_t) -1 || mbclen == 0
+		 || (mbclen == (size_t) -2 && pstr->bufs_len >= pstr->len))
 	  {
 	    /* It is an invalid character or '\0'.  Just use the byte.  */
 	    int ch = pstr->raw_mbs[pstr->raw_mbs_idx + src_idx];

posix/regexec.c

@@ -1,5 +1,5 @@
 /* Extended regular expression matching and search library.
-   Copyright (C) 2002-2005, 2007, 2009, 2010 Free Software Foundation, Inc.
+   Copyright (C) 2002-2005,2007,2009,2010,2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Isamu Hasegawa <isamu@yamato.ibm.com>.
 
@@ -1156,7 +1156,8 @@ check_matching (re_match_context_t *mctx, int fl_longest_match,
       re_dfastate_t *old_state = cur_state;
       int next_char_idx = re_string_cur_idx (&mctx->input) + 1;
 
-      if (BE (next_char_idx >= mctx->input.bufs_len, 0)
+      if ((BE (next_char_idx >= mctx->input.bufs_len, 0)
+	   && mctx->input.bufs_len < mctx->input.len)
 	  || (BE (next_char_idx >= mctx->input.valid_len, 0)
 	      && mctx->input.valid_len < mctx->input.len))
 	{
@@ -1732,7 +1733,8 @@ clean_state_log_if_needed (re_match_context_t *mctx, int next_state_log_idx)
 {
   int top = mctx->state_log_top;
 
-  if (next_state_log_idx >= mctx->input.bufs_len
+  if ((next_state_log_idx >= mctx->input.bufs_len
+       && mctx->input.bufs_len < mctx->input.len)
       || (next_state_log_idx >= mctx->input.valid_len
 	  && mctx->input.valid_len < mctx->input.len))
     {
@@ -4111,7 +4113,7 @@ extend_buffers (re_match_context_t *mctx)
     return REG_ESPACE;
 
   /* Double the lengthes of the buffers.  */
-  ret = re_string_realloc_buffers (pstr, pstr->bufs_len * 2);
+  ret = re_string_realloc_buffers (pstr, MIN (pstr->len, pstr->bufs_len * 2));
   if (BE (ret != REG_NOERROR, 0))
     return ret;