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Rewrite cookie parser to be more tolerant of junk input

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No longer need urldb_init; remove it.

svn path=/trunk/netsurf/; revision=2643
This commit is contained in:
John Mark Bell 2006-06-24 15:44:48 +00:00
parent bb91584f7c
commit a63221a624
3 changed files with 235 additions and 248 deletions
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478
content/urldb.c
View File

@ -240,7 +240,8 @@ static int urldb_search_match_prefix(const struct host_part *a,
/* Cookies */
static struct cookie *urldb_parse_cookie(const char *url,
const char *cookie);
const char **cookie);
static bool urldb_parse_avpair(struct cookie *c, char *n, char *v);
static bool urldb_insert_cookie(struct cookie *c, const char *scheme,
const char *url);
static void urldb_free_cookie(struct cookie *c);
@ -267,24 +268,6 @@ static struct search_node *search_trees[NUM_SEARCH_TREES] = {
#define COOKIE_FILE_VERSION 100
#define URL_FILE_VERSION 106
regex_t expires_re;
/**
* Initialise URL database code
*
* This should be called before any other urldb functions
*/
void urldb_init(void)
{
regcomp_wrapper(&expires_re, "[a-zA-Z]{3},[[:space:]]" // "Wdy, "
"[0-9]{2}[[:space:]-]" // "DD[ -]"
"[a-zA-Z]{3}[[:space:]-]" // "MMM[ -]"
"[0-9]{2,4}[[:space:]]" // "YY(YY)? "
"[0-9]{2}(:[0-9]{2}){2}" // "HH:MM:SS"
"[[:space:]]GMT", // " GMT"
REG_EXTENDED);
}
/**
* Import an URL database from file, replacing any existing database
*
@ -2498,8 +2481,7 @@ char *urldb_get_cookie(const char *url, const char *referer)
*/
bool urldb_set_cookie(const char *header, const char *url)
{
char cookie[8192];
const char *cur = header, *comma, *end;
const char *cur = header, *end;
char *path, *host, *scheme, *urlt;
url_func_result res;
@ -2536,34 +2518,11 @@ bool urldb_set_cookie(const char *header, const char *url)
end = cur + strlen(cur) - 2 /* Trailing CRLF */;
/* Find comma, if any */
comma = strchr(cur, ',');
if (comma) {
/* Check for Expires avpair: Wdy, DD-Mon-YYYY HH:MM:SS GMT */
/* Date parts of the form "DD Mon YYYY" have been seen in
* the wild, so we accept them too even though they're not
* strictly correct - it's more important to match something
* that looks like an Expires avpair than be strict here (as
* we're simply looking for the end of the cookie
* declaration) */
if (regexec(&expires_re, comma - 3, 0, NULL, 0) == 0) {
/* Part of Expires avpair => look for next comma */
comma = strchr(comma + 1, ',');
}
}
if (!comma) {/* Yes, if; not else - Expires check may modify comma */
/* No comma => 1 cookie in this header */
comma = end;
}
do {
struct cookie *c;
char *dot;
snprintf(cookie, sizeof cookie, "%.*s", comma - cur, cur);
c = urldb_parse_cookie(url, cookie);
c = urldb_parse_cookie(url, &cur);
if (!c) {
/* failed => stop parsing */
goto error;
@ -2571,14 +2530,20 @@ bool urldb_set_cookie(const char *header, const char *url)
/* validate cookie */
/* Cookie path must be a prefix of URL path */
/* 4.2.2:i Cookie must have NAME and VALUE */
if (!c->name || !c->value) {
urldb_free_cookie(c);
goto error;
}
/* 4.3.2:i Cookie path must be a prefix of URL path */
if (strncmp(c->path, path, strlen(c->path)) != 0 ||
strlen(c->path) > strlen(path)) {
urldb_free_cookie(c);
goto error;
}
/* Cookie domain must contain embedded dots */
/* 4.3.2:ii Cookie domain must contain embedded dots */
dot = strchr(c->domain + 1, '.');
if (!dot || *(dot + 1) == '\0') {
/* no embedded dots */
@ -2590,6 +2555,7 @@ bool urldb_set_cookie(const char *header, const char *url)
if (strcasecmp(host, c->domain) != 0) {
int hlen, dlen;
/* 4.3.2:iii */
if (host[0] >= '0' && host[0] <= '9') {
/* IP address, so no partial match */
urldb_free_cookie(c);
@ -2610,7 +2576,7 @@ bool urldb_set_cookie(const char *header, const char *url)
goto error;
}
/* Ensure H contains no dots */
/* 4.3.2:iv Ensure H contains no dots */
for (int i = 0; i < (hlen - dlen); i++)
if (host[i] == '.') {
urldb_free_cookie(c);
@ -2621,23 +2587,7 @@ bool urldb_set_cookie(const char *header, const char *url)
/* Now insert into database */
if (!urldb_insert_cookie(c, scheme, urlt))
goto error;
cur = comma + 1;
if (cur < end) {
comma = strchr(cur, ',');
if (comma) {
/* Check if it's an Expires avpair */
if (regexec(&expires_re, comma - 3, 0,
NULL, 0) == 0) {
/* Part of Expires avpair =>
* look for next comma */
comma = strchr(comma + 1, ',');
}
}
if (!comma)
comma = end;
}
} while (comma && cur < end);
} while (cur < end);
free(host);
free(path);
@ -2659,173 +2609,130 @@ error:
* Parse a cookie
*
* \param url URL being fetched
* \param cookie Cookie string
* \param cookie Pointer to cookie string (updated on exit)
* \return Pointer to cookie structure (on heap, caller frees) or NULL
*/
struct cookie *urldb_parse_cookie(const char *url, const char *cookie)
struct cookie *urldb_parse_cookie(const char *url, const char **cookie)
{
struct cookie *c;
const char *cur;
char name[1024], value[4096];
const char *cur = cookie, *semi, *end;
time_t max_age = 0, expires = 0;
bool had_max_age = false, had_expires = false;
char *n = name, *v = value;
bool had_equals = false;
bool quoted = false;
url_func_result res;
assert(url && cookie);
assert(url && cookie && *cookie);
c = calloc(1, sizeof(struct cookie));
if (!c)
return NULL;
end = cur + strlen(cur);
c->expires = -1;
/* Find semicolon */
semi = strchr(cur, ';');
if (!semi)
semi = end;
name[0] = '\0';
value[0] = '\0';
/* process name-value pairs */
do {
char *equals = strchr(cur, '=');
int vlen;
name[0] = value[0] = '\0';
if (equals && equals < semi) {
char *n, *v;
/* name = value */
if (sscanf(cur, "%1023[^=]=%4095[^;]",
name, value) != 2)
break;
/* Strip whitespace from start of name */
for (n = name; *n; n++) {
if (*n != ' ' && *n != '\t')
break;
}
/* Strip whitespace from end of name */
for (vlen = strlen(name); vlen; vlen--) {
if (name[vlen] == ' ' || name[vlen] == '\t')
name[vlen] = '\0';
else
break;
}
/* Strip whitespace from start of value */
for (v = value; *v; v++) {
if (*v != ' ' && *v != '\t')
break;
}
/* Strip quote from start of value */
if (*v == '"')
v++;
/* Strip whitespace from end of value */
for (vlen = strlen(value); vlen; vlen--) {
if (value[vlen] == ' ' ||
value[vlen] == '\t')
value[vlen] = '\0';
else
break;
}
/* Strip quote from end of value */
if (value[vlen] == '"')
value[vlen] = '\0';
if (!c->comment &&
strcasecmp(n, "Comment") == 0) {
c->comment = strdup(v);
if (!c->comment)
break;
} else if (!c->domain &&
strcasecmp(n, "Domain") == 0) {
if (v[0] == '.') {
/* Domain must start with a dot */
c->domain_from_set = true;
c->domain = strdup(v);
if (!c->domain)
break;
}
} else if (strcasecmp(n, "Max-Age") == 0) {
int temp = atoi(v);
had_max_age = true;
if (temp == 0)
/* Special case - 0 means delete */
max_age = 0;
else
max_age = time(NULL) + temp;
} else if (!c->path &&
strcasecmp(n, "Path") == 0) {
c->path_from_set = true;
c->path = strdup(v);
if (!c->path)
break;
} else if (strcasecmp(n, "Version") == 0) {
c->version = atoi(v);
} else if (strcasecmp(n, "Expires") == 0) {
char *datenoday;
/* Strip dayname from date (these are hugely
* variable and liable to break the parser.
* They also serve no useful purpose) */
for (datenoday = v;
*datenoday && !isdigit(*datenoday);
datenoday++)
; /* do nothing */
had_expires = true;
expires = curl_getdate(datenoday, NULL);
if (expires == -1) {
/* assume we have an unrepresentable
* date => force it to the maximum
* possible value of a 32bit time_t
* (this may break in 2038. We'll
* deal with that once we come to
* it) */
expires = (time_t)0x7fffffff;
}
} else if (!c->name) {
c->name = strdup(n);
c->value = strdup(v);
if (!c->name || !c->value)
break;
}
} else {
char *n;
/* name */
if (sscanf(cur, "%1023[^;] ", name) != 1)
break;
/* Strip whitespace from start of name */
for (n = name; *n; n++) {
if (*n != ' ' && *n != '\t')
break;
}
/* Strip whitespace from end of name */
for (vlen = strlen(name); vlen; vlen--) {
if (name[vlen] == ' ' || name[vlen] == '\t')
name[vlen] = '\0';
else
break;
}
if (strcasecmp(n, "Secure") == 0)
c->secure = true;
for (cur = *cookie; *cur && *cur != '\r' && *cur != '\n'; cur++) {
if (had_equals && (*cur == '"' || *cur == '\'')) {
/* Only values may be quoted */
quoted = !quoted;
continue;
}
cur = semi + 1;
if (cur < end) {
semi = strchr(cur, ';');
if (!quoted && !had_equals && *cur == '=') {
/* First equals => attr-value separator */
had_equals = true;
continue;
}
if (!quoted && *cur == ';') {
/* Semicolon => end of current avpair */
/* NUL-terminate tokens */
*n = '\0';
*v = '\0';
if (!urldb_parse_avpair(c, name, value)) {
/* Memory exhausted */
urldb_free_cookie(c);
return NULL;
}
/* And reset to start */
n = name;
v = value;
had_equals = false;
continue;
}
/* And now handle commas. These are a pain as they may mean
* any of the following:
*
* + End of cookie
* + Day separator in Expires avpair
* + (Invalid) comma in unquoted value
*
* Therefore, in order to handle all 3 cases (2 and 3 are
* identical, the difference being that 2 is in the spec and
* 3 isn't), we need to determine where the comma actually
* lies. We use the following heuristic:
*
* Given a comma at the current input position, find the
* immediately following semicolon (or end of input if none
* found). Then, consider the input characters between
* these two positions. If any of these characters is an
* '=', we must assume that the comma signified the end of
* the current cookie.
*
* This holds as the first avpair of any cookie must be
* NAME=VALUE, so the '=' is guaranteed to appear in the
* case where the comma marks the end of a cookie.
*
* This will fail, however, in the case where '=' appears in
* the value of the current avpair after the comma or the
* subsequent cookie does not start with NAME=VALUE. Neither
* of these is particularly likely and if they do occur, the
* website is more broken than we can be bothered to handle.
*/
if (!quoted && *cur == ',') {
/* Find semi-colon, if any */
const char *p;
const char *semi = strchr(cur + 1, ';');
if (!semi)
semi = end;
}
} while(semi && cur < end);
semi = cur + strlen(cur) - 2 /* CRLF */;
if (cur < end) {
/* parsing failed */
/* Look for equals sign between comma and semi */
for (p = cur + 1; p < semi; p++)
if (*p == '=')
break;
if (p == semi) {
/* none found => comma internal to value */
/* do nothing */
} else {
/* found one => comma marks end of cookie */
cur++;
break;
}
}
/* Accumulate into buffers, always leaving space for a NUL */
if (!had_equals) {
if (n < name + 1023)
*n++ = *cur;
} else {
if (v < value + 4095)
*v++ = *cur;
}
}
/* Parse final avpair */
*n = '\0';
*v = '\0';
if (!urldb_parse_avpair(c, name, value)) {
/* Memory exhausted */
urldb_free_cookie(c);
return NULL;
}
@ -2847,20 +2754,117 @@ struct cookie *urldb_parse_cookie(const char *url, const char *cookie)
}
}
if (had_max_age && had_expires) {
/* Max age takes precedence iff version 1 or later */
c->expires =
c->version == COOKIE_NETSCAPE ? expires : max_age;
} else if (had_max_age) {
c->expires = max_age;
} else if (had_expires) {
c->expires = expires;
} else
if (c->expires == -1)
c->expires = 1;
/* Write back current position */
*cookie = cur;
return c;
}
/**
* Parse a cookie avpair
*
* \param c Cookie struct to populate
* \param n Name component
* \param v Value component
* \return true on success, false on memory exhaustion
*/
bool urldb_parse_avpair(struct cookie *c, char *n, char *v)
{
int vlen;
assert(c && n && v);
/* Strip whitespace from start of name */
for (; *n; n++) {
if (*n != ' ' && *n != '\t')
break;
}
/* Strip whitespace from end of name */
for (vlen = strlen(n); vlen; vlen--) {
if (n[vlen] == ' ' || n[vlen] == '\t')
n[vlen] = '\0';
else
break;
}
/* Strip whitespace from start of value */
for (; *v; v++) {
if (*v != ' ' && *v != '\t')
break;
}
/* Strip whitespace from end of value */
for (vlen = strlen(v); vlen; vlen--) {
if (v[vlen] == ' ' || v[vlen] == '\t')
v[vlen] = '\0';
else
break;
}
if (!c->comment && strcasecmp(n, "Comment") == 0) {
c->comment = strdup(v);
if (!c->comment)
return false;
} else if (!c->domain && strcasecmp(n, "Domain") == 0) {
if (v[0] == '.') {
/* Domain must start with a dot */
c->domain_from_set = true;
c->domain = strdup(v);
if (!c->domain)
return false;
}
} else if (strcasecmp(n, "Max-Age") == 0) {
int temp = atoi(v);
if (temp == 0)
/* Special case - 0 means delete */
c->expires = 0;
else
c->expires = time(NULL) + temp;
} else if (!c->path && strcasecmp(n, "Path") == 0) {
c->path_from_set = true;
c->path = strdup(v);
if (!c->path)
return false;
} else if (strcasecmp(n, "Version") == 0) {
c->version = atoi(v);
} else if (strcasecmp(n, "Expires") == 0) {
char *datenoday;
time_t expires;
/* Strip dayname from date (these are hugely
* variable and liable to break the parser.
* They also serve no useful purpose) */
for (datenoday = v; *datenoday && !isdigit(*datenoday);
datenoday++)
; /* do nothing */
expires = curl_getdate(datenoday, NULL);
if (expires == -1) {
/* assume we have an unrepresentable
* date => force it to the maximum
* possible value of a 32bit time_t
* (this may break in 2038. We'll
* deal with that once we come to
* it) */
expires = (time_t)0x7fffffff;
}
c->expires = expires;
} else if (strcasecmp(n, "Secure") == 0) {
c->secure = true;
} else if (!c->name) {
c->name = strdup(n);
c->value = strdup(v);
if (!c->name || !c->value)
return false;
}
return true;
}
/**
* Insert a cookie into the database
*
@ -3242,18 +3246,6 @@ void urldb_save_cookie_paths(FILE *fp, struct path_data *parent)
#ifdef TEST_URLDB
const char *inputs[] = {
"day, 16-Jun-2006 01:10:16 GMT",
"day, 16 Jun 2006 01:10:16 GMT",
"day, 16-Jun-06 01:10:16 GMT",
"day, 16 Jun 06 01:10:16 GMT",
"Fri, 16-Jun-2006 01:10:16 GMT",
"Fri, 16 Jun 2006 01:10:16 GMT",
"Fri, 16-Jun-06 01:10:16 GMT",
"Fri, 16 Jun 06 01:10:16 GMT"
};
#define N_INPUTS (sizeof(inputs) / sizeof(inputs[0]))
int option_expire_url = 0;
void die(const char *error)
@ -3276,12 +3268,6 @@ int main(void)
url_init();
urldb_init();
for (i = 0; i != N_INPUTS; i++)
if (regexec(&expires_re, inputs[i], 0, NULL, 0))
LOG(("Failed to match regex %d\n", i));
h = urldb_add_host("127.0.0.1");
if (!h) {
LOG(("failed adding host"));
@ -3317,9 +3303,15 @@ int main(void)
return 1;
}
urldb_set_cookie("mmblah=admin; path=/; expires=Thur, 31-Dec-2099 00:00:00 GMT\r\n", "http://www.minimarcos.org.uk/cgi-bin/forum/Blah.pl?,v=login,p=2");
urldb_set_cookie("mmblah=foo; path=/; expires=Thur, 31-Dec-2099 00:00:00 GMT\r\n", "http://www.minimarcos.org.uk/cgi-bin/forum/Blah.pl?,v=login,p=2");
urldb_set_cookie("BlahPW=B%7Eyx.22dJsrwk; path=/; expires=Thur, 31-Dec-2099 00:00:00 GMT\r\n", "http://www.minimarcos.org.uk/cgi-bin/forum/Blah.pl?,v=login,p=2");
urldb_set_cookie("BlahPW=bar; path=/; expires=Thur, 31-Dec-2099 00:00:00 GMT\r\n", "http://www.minimarcos.org.uk/cgi-bin/forum/Blah.pl?,v=login,p=2");
urldb_set_cookie("details=foo|bar|Sun, 03-Jun-2007;expires=Mon, 24-Jul-2006 09:53:45 GMT", "http://ccdb.cropcircleresearch.com/");
urldb_set_cookie("PREF=ID=a:TM=b:LM=c:S=d; path=/; domain=.google.com", "http://www.google.com/");
urldb_set_cookie("test=foo, bar, baz; path=/, quux=blah; path=/", "http://www.bbc.co.uk/");
urldb_dump();

3
content/urldb.h
View File

@ -25,9 +25,6 @@ struct url_data {
struct bitmap;
/* Initialisation */
void urldb_init(void);
/* Persistence support */
void urldb_load(const char *filename);
void urldb_save(const char *filename);

2
desktop/netsurf.c
View File

@ -15,7 +15,6 @@
#include "netsurf/utils/config.h"
#include "netsurf/content/fetch.h"
#include "netsurf/content/fetchcache.h"
#include "netsurf/content/urldb.h"
#include "netsurf/desktop/netsurf.h"
#include "netsurf/desktop/browser.h"
#include "netsurf/desktop/gui.h"
@ -78,7 +77,6 @@ void netsurf_init(int argc, char** argv)
lib_init();
url_init();
urldb_init();
gui_init(argc, argv);
setlocale(LC_ALL, "");
fetch_init();