[src/trunk]: src/usr.bin/make make(1): fix out-of-bounds pointer in ParseTrac...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f32f197fc546
branches:  trunk
changeset: 941873:f32f197fc546
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat Oct 31 23:39:01 2020 +0000

description:
make(1): fix out-of-bounds pointer in ParseTrackInput

diffstat:

 usr.bin/make/parse.c |  64 +++++++++++++++++++++++++++++++++------------------
 1 files changed, 41 insertions(+), 23 deletions(-)

diffs (90 lines):

diff -r 23e16a4ea585 -r f32f197fc546 usr.bin/make/parse.c
--- a/usr.bin/make/parse.c      Sat Oct 31 23:23:22 2020 +0000
+++ b/usr.bin/make/parse.c      Sat Oct 31 23:39:01 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: parse.c,v 1.417 2020/10/31 23:10:06 rillig Exp $       */
+/*     $NetBSD: parse.c,v 1.418 2020/10/31 23:39:01 rillig Exp $       */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -117,7 +117,7 @@
 #include "pathnames.h"
 
 /*     "@(#)parse.c    8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: parse.c,v 1.417 2020/10/31 23:10:06 rillig Exp $");
+MAKE_RCSID("$NetBSD: parse.c,v 1.418 2020/10/31 23:39:01 rillig Exp $");
 
 /* types and constants */
 
@@ -2351,32 +2351,50 @@
     }
 }
 
+static Boolean
+StrContainsWord(const char *str, const char *word)
+{
+    const char *val = str;
+    size_t valLen = strlen(val);
+    size_t wordLen = strlen(word);
+    const char *end;
+
+    if (valLen < wordLen)
+       return FALSE;           /* str is too short to contain word */
+
+    end = val + valLen - wordLen;
+    for (; val != NULL; val = strchr(val, ' ')) {
+       if (*val == ' ')
+           val++;
+       if (val > end)
+           return FALSE;       /* cannot contain word */
+
+       if (memcmp(val, word, wordLen) == 0 &&
+           (val[wordLen] == '\0' || val[wordLen] == ' '))
+           return TRUE;
+    }
+    return FALSE;
+}
+
+/* XXX: Searching through a set of words with this linear search is
+ * inefficient for variables that contain thousands of words. */
+static Boolean
+VarContainsWord(const char *varname, const char *word)
+{
+    void *val_freeIt;
+    const char *val = Var_Value(varname, VAR_GLOBAL, &val_freeIt);
+    Boolean found = val != NULL && StrContainsWord(val, word);
+    bmake_free(val_freeIt);
+    return found;
+}
+
 /* Track the makefiles we read - so makefiles can set dependencies on them.
  * Avoid adding anything more than once. */
 static void
 ParseTrackInput(const char *name)
 {
-    void *old_freeIt = NULL;
-
-    const char *old = Var_Value(MAKE_MAKEFILES, VAR_GLOBAL, &old_freeIt);
-    if (old != NULL) {
-       size_t name_len = strlen(name);
-       /* XXX: undefined behavior if name_len > strlen(old) */
-       const char *ep = old + strlen(old) - name_len;
-       /* does it contain name? */
-       for (; old != NULL; old = strchr(old, ' ')) {
-           if (*old == ' ')
-               old++;
-           if (old > ep)
-               break;          /* cannot contain name */
-           if (memcmp(old, name, name_len) == 0 &&
-               (old[name_len] == '\0' || old[name_len] == ' '))
-               goto cleanup;
-       }
-    }
-    Var_Append(MAKE_MAKEFILES, name, VAR_GLOBAL);
-cleanup:
-    bmake_free(old_freeIt);
+    if (!VarContainsWord(MAKE_MAKEFILES, name))
+       Var_Append(MAKE_MAKEFILES, name, VAR_GLOBAL);
 }