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fix out-of-bounds read in mod_proxy_html metafix #783

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fix out-of-bounds read in mod_proxy_html metafix #783

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3 changes: 3 additions & 0 deletions changes-entries/proxy-html-metafix-bounds.txt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
*) mod_proxy_html: Fix out-of-bounds reads in metafix() when a
<meta http-equiv> tag appears at the end of the response buffer with
ProxyHTMLMeta enabled. [Arshiya Tabasum]
21 changes: 11 additions & 10 deletions modules/filters/mod_proxy_html.c
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Original file line number Diff line number Diff line change
Expand Up @@ -689,6 +689,7 @@ static meta *metafix(request_rec *r, const char *buf, apr_size_t len)
size_t offs = 0;
const char *p;
const char *q;
const char *end = buf + len;
char *header;
char *content;
ap_regmatch_t pmatch[2];
Expand All @@ -699,8 +700,8 @@ static meta *metafix(request_rec *r, const char *buf, apr_size_t len)
header = NULL;
content = NULL;
p = buf+offs+pmatch[1].rm_eo;
while (!apr_isalpha(*++p));
for (q = p; apr_isalnum(*q) || (*q == '-'); ++q);
while (++p < end && !apr_isalpha(*p));
for (q = p; q < end && (apr_isalnum(*q) || (*q == '-')); ++q);
header = apr_pstrmemdup(r->pool, p, q-p);
if (!ap_cstr_casecmpn(header, "Content-Type", 12)) {
ret = apr_palloc(r->pool, sizeof(meta));
Expand All @@ -713,22 +714,22 @@ static meta *metafix(request_rec *r, const char *buf, apr_size_t len)
pmatch[0].rm_eo - pmatch[0].rm_so);
/* if it doesn't contain "content", ignore, don't crash! */
if (p != NULL) {
while (*p) {
while (p < end && *p) {
p += 7;
while (apr_isspace(*p))
while (p < end && apr_isspace(*p))
++p;
/* XXX Should we search for another content= pattern? */
if (*p != '=')
if (p >= end || *p != '=')
break;
while (*p && apr_isspace(*++p));
if ((*p == '\'') || (*p == '"')) {
while (++p < end && apr_isspace(*p));
if (p < end && ((*p == '\'') || (*p == '"'))) {
delim = *p++;
for (q = p; *q && *q != delim; ++q);
for (q = p; q < end && *q != delim; ++q);
/* No terminating delimiter found? Skip the bogus directive */
if (*q != delim)
if (q >= end || *q != delim)
break;
} else {
for (q = p; *q && !apr_isspace(*q) && (*q != '>'); ++q);
for (q = p; q < end && !apr_isspace(*q) && (*q != '>'); ++q);
}
content = apr_pstrmemdup(r->pool, p, q-p);
break;
Expand Down