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Work around a libidn <= 1.30 vulnerability

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* src/iri.c: Add _utf8_is_valid() to check UTF-8 sequences before
  passing them to idna_to_ascii_8z().
This commit is contained in:
Tim Rühsen 2015-06-30 09:55:14 +02:00
parent ae58d8a78b
commit 77f5a27e65
1 changed files with 52 additions and 0 deletions
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52
src/iri.c
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@ -219,6 +219,50 @@ locale_to_utf8 (const char *str)
return str; return str;
} }
/*
* Work around a libidn <= 1.30 vulnerability.
*
* The function checks for a valid UTF-8 character sequence before
* passing it to idna_to_ascii_8z().
*
* [1] http://lists.gnu.org/archive/html/help-libidn/2015-05/msg00002.html
* [2] https://lists.gnu.org/archive/html/bug-wget/2015-06/msg00002.html
* [3] http://curl.haxx.se/mail/lib-2015-06/0143.html
*/
static bool
_utf8_is_valid(const char *utf8)
{
const unsigned char *s = (const unsigned char *) utf8;
while (*s)
{
if ((*s & 0x80) == 0) /* 0xxxxxxx ASCII char */
s++;
else if ((*s & 0xE0) == 0xC0) /* 110xxxxx 10xxxxxx */
{
if ((s[1] & 0xC0) != 0x80)
return false;
s+=2;
}
else if ((*s & 0xF0) == 0xE0) /* 1110xxxx 10xxxxxx 10xxxxxx */
{
if ((s[1] & 0xC0) != 0x80 || (s[2] & 0xC0) != 0x80)
return false;
s+=3;
}
else if ((*s & 0xF8) == 0xF0) /* 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
{
if ((s[1] & 0xC0) != 0x80 || (s[2] & 0xC0) != 0x80 || (s[3] & 0xC0) != 0x80)
return false;
s+=4;
}
else
return false;
}
return true;
}
/* Try to "ASCII encode" UTF-8 host. Return the new domain on success or NULL /* Try to "ASCII encode" UTF-8 host. Return the new domain on success or NULL
on error. */ on error. */
char * char *
@ -235,6 +279,14 @@ idn_encode (struct iri *i, char *host)
return NULL; /* Nothing to encode or an error occured */ return NULL; /* Nothing to encode or an error occured */
} }
if (!_utf8_is_valid(utf8_encoded ? utf8_encoded : host))
{
logprintf (LOG_VERBOSE, _("Invalid UTF-8 sequence: %s\n"),
quote(utf8_encoded ? utf8_encoded : host));
xfree (utf8_encoded);
return NULL;
}
/* Store in ascii_encoded the ASCII UTF-8 NULL terminated string */ /* Store in ascii_encoded the ASCII UTF-8 NULL terminated string */
ret = idna_to_ascii_8z (utf8_encoded ? utf8_encoded : host, &ascii_encoded, IDNA_FLAGS); ret = idna_to_ascii_8z (utf8_encoded ? utf8_encoded : host, &ascii_encoded, IDNA_FLAGS);
xfree (utf8_encoded); xfree (utf8_encoded);