Package: link-grammar Version: 4.2.2-1 Severity: grave Tags: security patch
Hi,
the following CVE (Common Vulnerabilities & Exposures) id was
published for link-grammar.
CVE-2007-5395[0]:
| Stack-based buffer overflow in the separate_word function in
| tokenize.c in Link Grammar 4.1b and possibly other versions, as used
| in AbiWord Link Grammar 4.2.4, allows remote attackers to execute
| arbitrary code via a long word, as reachable through the
| separate_sentence function.
A patch for this extracted from upstream CVS is attached.
This is the cvs log for this fix:
RCS file: /cvsroot/link-grammar/link-grammar/tokenize.c,v
Working file: tokenize.c
head: 1.4
branch:
locks: strict
access list:
symbolic names:
link-grammar-4-2-4: 1.3
release-4-2-2: 1.2
release-4-2-1: 1.2
release-4-1-3: 1.1.1.1
release-4-1-1: 1.1.1.1
begin: 1.1.1.1
start: 1.1.1
keyword substitution: kv
total revisions: 5; selected revisions: 1
description:
----------------------------
revision 1.4
date: 2007/10/27 19:03:40; author: dom; state: Exp; lines: +15 -14
Secunia advisory SA27340 and CVE identifier CVE-2007-5395.
The vulnerability is caused due to a boundary error within the
"separate_word()" function in tokenize.c when processing overly long
words (over 61 bytes). This can be exploited to cause a stack-based
buffer overflow via a specially crafted sentence passed to the
"separate_sentence()" function.
If you fix this vulnerability please also include the CVE id
in your changelog entry.
For further information:
[0] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-5395
Kind regards
Nico
--
Nico Golde - http://www.ngolde.de - [EMAIL PROTECTED] - GPG: 0x73647CFF
For security reasons, all text in this mail is double-rot13 encrypted.
diff -u -r1.3 -r1.4
--- link-grammar/tokenize.c 16 Aug 2006 17:07:02 -0000 1.3
+++ link-grammar/tokenize.c 27 Oct 2007 19:03:40 -0000 1.4
@@ -172,7 +172,8 @@
used in a sentence.
*/
-
+#undef MIN
+#define MIN(a, b) (((a) < (b)) ? (a) : (b))
static int separate_word(Sentence sent, char *w, char *wend, int is_first_word, int quote_found) {
/* w points to a string, wend points to the char one after the end. The
@@ -256,8 +257,8 @@
for (n_r_stripped = 0; n_r_stripped < MAX_STRIP; n_r_stripped++) {
- strncpy(word, w, wend-w);
- word[wend-w] = '\0';
+ strncpy(word, w, MIN(wend-w, MAX_WORD));
+ word[MIN(wend-w, MAX_WORD)] = '\0';
if (wend == w) break; /* it will work without this */
if (boolean_dictionary_lookup(sent->dict, word) || is_initials_word(word)) break;
@@ -285,8 +286,8 @@
/* Now we strip off suffixes...w points to the remaining word, "wend" to the end of the word. */
s_stripped = -1;
- strncpy(word, w, wend-w);
- word[wend-w] = '\0';
+ strncpy(word, w, MIN(wend-w, MAX_WORD));
+ word[MIN(wend-w, MAX_WORD)] = '\0';
word_is_in_dict=0;
if (boolean_dictionary_lookup(sent->dict, word) || is_initials_word(word)) word_is_in_dict=1;
@@ -309,16 +310,16 @@
if(s_ok==1 || i==s_strippable) {
- strncpy(newword, w, (wend-len)-w);
- newword[(wend-len)-w] = '\0';
+ strncpy(newword, w, MIN((wend-len)-w, MAX_WORD));
+ newword[MIN((wend-len)-w, MAX_WORD)] = '\0';
/* Check if the remainder is in the dictionary; for the no-suffix case, it won't be */
if (boolean_dictionary_lookup(sent->dict, newword)) {
if(verbosity>1) if(i< s_strippable) printf("Splitting word into two: %s-%s\n", newword, suffix[i]);
s_stripped = i;
wend -= len;
- strncpy(word, w, wend-w);
- word[wend-w] = '\0';
+ strncpy(word, w, MIN(wend-w, MAX_WORD));
+ word[MIN(wend-w, MAX_WORD)] = '\0';
break;
}
@@ -326,17 +327,17 @@
else {
for (j=0; j<p_strippable; j++) {
if (strncmp(w, prefix[j], strlen(prefix[j])) == 0) {
- strncpy(newword, w+strlen(prefix[j]), (wend-len)-(w+strlen(prefix[j])));
- newword[(wend-len)-(w+strlen(prefix[j]))]='\0';
+ strncpy(newword, w+strlen(prefix[j]), MIN((wend-len)-(w+strlen(prefix[j])), MAX_WORD));
+ newword[MIN((wend-len)-(w+strlen(prefix[j])), MAX_WORD)]='\0';
if(boolean_dictionary_lookup(sent->dict, newword)) {
if(verbosity>1) if(i < s_strippable) printf("Splitting word into three: %s-%s-%s\n", prefix[j], newword, suffix[i]);
if (!issue_sentence_word(sent, prefix[j])) return FALSE;
if(i < s_strippable) s_stripped = i;
wend -= len;
w += strlen(prefix[j]);
- strncpy(word, w, wend-w);
- word[wend-w] = '\0';
- break;
+ strncpy(word, w, MIN(wend-w, MAX_WORD));
+ word[MIN(wend-w, MAX_WORD)] = '\0';
+ break;
}
}
}
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