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Commits (9)
o Major bugfixes (security, directory authority, denial-of-service):
- Fix a bug that could have allowed an attacker to force a
directory authority to use up all its RAM by passing it a
maliciously crafted protocol versions string. Fixes bug 25517;
bugfix on 0.2.9.4-alpha. This issue is also tracked as
TROVE-2018-005.
......@@ -4,7 +4,7 @@ dnl Copyright (c) 2007-2017, The Tor Project, Inc.
dnl See LICENSE for licensing information
AC_PREREQ([2.63])
AC_INIT([tor],[0.3.3.5-rc-dev])
AC_INIT([tor],[0.3.3.6])
AC_CONFIG_SRCDIR([src/or/main.c])
AC_CONFIG_MACRO_DIR([m4])
......
......@@ -8,7 +8,7 @@
!include "LogicLib.nsh"
!include "FileFunc.nsh"
!insertmacro GetParameters
!define VERSION "0.3.3.5-rc-dev"
!define VERSION "0.3.3.6"
!define INSTALLER "tor-${VERSION}-win32.exe"
!define WEBSITE "https://www.torproject.org/"
!define LICENSE "LICENSE"
......
......@@ -2963,6 +2963,12 @@ dirserv_generate_networkstatus_vote_obj(crypto_pk_t *private_key,
microdescriptors = smartlist_new();
SMARTLIST_FOREACH_BEGIN(routers, routerinfo_t *, ri) {
/* If it has a protover list and contains a protocol name greater than
* MAX_PROTOCOL_NAME_LENGTH, skip it. */
if (ri->protocol_list &&
protover_contains_long_protocol_names(ri->protocol_list)) {
continue;
}
if (ri->cache_info.published_on >= cutoff) {
routerstatus_t *rs;
vote_routerstatus_t *vrs;
......
......@@ -53,6 +53,11 @@ static const struct {
#define N_PROTOCOL_NAMES ARRAY_LENGTH(PROTOCOL_NAMES)
/* Maximum allowed length of any single subprotocol name. */
// C_RUST_COUPLED: src/rust/protover/protover.rs
// `MAX_PROTOCOL_NAME_LENGTH`
static const unsigned MAX_PROTOCOL_NAME_LENGTH = 100;
/**
* Given a protocol_type_t, return the corresponding string used in
* descriptors.
......@@ -198,6 +203,15 @@ parse_single_entry(const char *s, const char *end_of_entry)
if (equals == s)
goto error;
/* The name must not be longer than MAX_PROTOCOL_NAME_LENGTH. */
if (equals - s > MAX_PROTOCOL_NAME_LENGTH) {
log_warn(LD_NET, "When parsing a protocol entry, I got a very large "
"protocol name. This is possibly an attack or a bug, unless "
"the Tor network truly supports protocol names larger than "
"%ud characters. The offending string was: %s",
MAX_PROTOCOL_NAME_LENGTH, escaped(out->name));
goto error;
}
out->name = tor_strndup(s, equals-s);
tor_assert(equals < end_of_entry);
......@@ -262,6 +276,18 @@ parse_protocol_list(const char *s)
return NULL;
}
/**
* Return true if the unparsed protover in <b>s</b> would contain a protocol
* name longer than MAX_PROTOCOL_NAME_LENGTH, and false otherwise.
*/
bool
protover_contains_long_protocol_names(const char *s)
{
if (!parse_protocol_list(s))
return true;
return false;
}
/**
* Given a protocol type and version number, return true iff we know
* how to speak that protocol.
......@@ -439,6 +465,14 @@ expand_protocol_list(const smartlist_t *protos)
SMARTLIST_FOREACH_BEGIN(protos, const proto_entry_t *, ent) {
const char *name = ent->name;
if (strlen(name) > MAX_PROTOCOL_NAME_LENGTH) {
log_warn(LD_NET, "When expanding a protocol entry, I got a very large "
"protocol name. This is possibly an attack or a bug, unless "
"the Tor network truly supports protocol names larger than "
"%ud characters. The offending string was: %s",
MAX_PROTOCOL_NAME_LENGTH, escaped(name));
continue;
}
SMARTLIST_FOREACH_BEGIN(ent->ranges, const proto_range_t *, range) {
uint32_t u;
for (u = range->low; u <= range->high; ++u) {
......
......@@ -10,7 +10,7 @@
#define TOR_PROTOVER_H
#include "container.h"
#include <stdbool.h>
/** The first version of Tor that included "proto" entries in its
* descriptors. Authorities should use this to decide whether to
* guess proto lines. */
......@@ -42,6 +42,7 @@ typedef enum protocol_type_t {
PRT_CONS,
} protocol_type_t;
bool protover_contains_long_protocol_names(const char *s);
int protover_all_supported(const char *s, char **missing);
int protover_is_supported_here(protocol_type_t pr, uint32_t ver);
const char *protover_get_supported_protocols(void);
......
......@@ -59,7 +59,8 @@ pub extern "C" fn protover_all_supported(
Err(_) => return 1,
};
let relay_proto_entry: UnvalidatedProtoEntry = match relay_version.parse() {
let relay_proto_entry: UnvalidatedProtoEntry =
match UnvalidatedProtoEntry::from_str_any_len(relay_version) {
Ok(n) => n,
Err(_) => return 1,
};
......@@ -181,6 +182,7 @@ pub extern "C" fn protover_get_supported_protocols() -> *const c_char {
pub extern "C" fn protover_compute_vote(
list: *const Stringlist,
threshold: c_int,
allow_long_proto_names: bool,
) -> *mut c_char {
if list.is_null() {
......@@ -195,9 +197,13 @@ pub extern "C" fn protover_compute_vote(
let mut proto_entries: Vec<UnvalidatedProtoEntry> = Vec::new();
for datum in data {
let entry: UnvalidatedProtoEntry = match datum.parse() {
Ok(x) => x,
Err(_) => continue,
let entry: UnvalidatedProtoEntry = match allow_long_proto_names {
true => match UnvalidatedProtoEntry::from_str_any_len(datum.as_str()) {
Ok(n) => n,
Err(_) => continue},
false => match datum.parse() {
Ok(n) => n,
Err(_) => continue},
};
proto_entries.push(entry);
}
......
......@@ -28,6 +28,9 @@ const FIRST_TOR_VERSION_TO_ADVERTISE_PROTOCOLS: &'static str = "0.2.9.3-alpha";
/// C_RUST_COUPLED: src/or/protover.c `MAX_PROTOCOLS_TO_EXPAND`
const MAX_PROTOCOLS_TO_EXPAND: usize = (1<<16);
/// The maximum size an `UnknownProtocol`'s name may be.
pub(crate) const MAX_PROTOCOL_NAME_LENGTH: usize = 100;
/// Currently supported protocols and their versions, as a byte-slice.
///
/// # Warning
......@@ -114,6 +117,18 @@ impl FromStr for UnknownProtocol {
type Err = ProtoverError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
if s.len() <= MAX_PROTOCOL_NAME_LENGTH {
Ok(UnknownProtocol(s.to_string()))
} else {
Err(ProtoverError::ExceedsNameLimit)
}
}
}
impl UnknownProtocol {
/// Create an `UnknownProtocol`, ignoring whether or not it
/// exceeds MAX_PROTOCOL_NAME_LENGTH.
fn from_str_any_len(s: &str) -> Result<Self, ProtoverError> {
Ok(UnknownProtocol(s.to_string()))
}
}
......@@ -428,6 +443,49 @@ impl UnvalidatedProtoEntry {
};
supported_versions.iter().any(|v| v.1 >= *vers)
}
/// Split a string containing (potentially) several protocols and their
/// versions into a `Vec` of tuples of string in `(protocol, versions)`
/// form.
///
/// # Inputs
///
/// A &str in the form `"Link=3-4 Cons=5"`.
///
/// # Returns
///
/// A `Result` whose `Ok` variant is a `Vec<(&str, &str)>` of `(protocol,
/// versions)`, or whose `Err` variant is a `ProtoverError`.
///
/// # Errors
///
/// This will error with a `ProtoverError::Unparseable` if any of the
/// following are true:
///
/// * If a protocol name is an empty string, e.g. `"Cons=1,3 =3-5"`.
/// * If a protocol name cannot be parsed as utf-8.
/// * If the version numbers are an empty string, e.g. `"Cons="`.
fn parse_protocol_and_version_str<'a>(protocol_string: &'a str)
-> Result<Vec<(&'a str, &'a str)>, ProtoverError>
{
let mut protovers: Vec<(&str, &str)> = Vec::new();
for subproto in protocol_string.split(' ') {
let mut parts = subproto.splitn(2, '=');
let name = match parts.next() {
Some("") => return Err(ProtoverError::Unparseable),
Some(n) => n,
None => return Err(ProtoverError::Unparseable),
};
let vers = match parts.next() {
Some(n) => n,
None => return Err(ProtoverError::Unparseable),
};
protovers.push((name, vers));
}
Ok(protovers)
}
}
impl FromStr for UnvalidatedProtoEntry {
......@@ -460,19 +518,10 @@ impl FromStr for UnvalidatedProtoEntry {
/// * If the version string is malformed. See `impl FromStr for ProtoSet`.
fn from_str(protocol_string: &str) -> Result<UnvalidatedProtoEntry, ProtoverError> {
let mut parsed: UnvalidatedProtoEntry = UnvalidatedProtoEntry::default();
let parts: Vec<(&str, &str)> =
UnvalidatedProtoEntry::parse_protocol_and_version_str(protocol_string)?;
for subproto in protocol_string.split(' ') {
let mut parts = subproto.splitn(2, '=');
let name = match parts.next() {
Some("") => return Err(ProtoverError::Unparseable),
Some(n) => n,
None => return Err(ProtoverError::Unparseable),
};
let vers = match parts.next() {
Some(n) => n,
None => return Err(ProtoverError::Unparseable),
};
for &(name, vers) in parts.iter() {
let versions = ProtoSet::from_str(vers)?;
let protocol = UnknownProtocol::from_str(name)?;
......@@ -482,6 +531,26 @@ impl FromStr for UnvalidatedProtoEntry {
}
}
impl UnvalidatedProtoEntry {
/// Create an `UnknownProtocol`, ignoring whether or not it
/// exceeds MAX_PROTOCOL_NAME_LENGTH.
pub(crate) fn from_str_any_len(protocol_string: &str)
-> Result<UnvalidatedProtoEntry, ProtoverError>
{
let mut parsed: UnvalidatedProtoEntry = UnvalidatedProtoEntry::default();
let parts: Vec<(&str, &str)> =
UnvalidatedProtoEntry::parse_protocol_and_version_str(protocol_string)?;
for &(name, vers) in parts.iter() {
let versions = ProtoSet::from_str(vers)?;
let protocol = UnknownProtocol::from_str_any_len(name)?;
parsed.insert(protocol, versions);
}
Ok(parsed)
}
}
/// Pretend a `ProtoEntry` is actually an `UnvalidatedProtoEntry`.
impl From<ProtoEntry> for UnvalidatedProtoEntry {
fn from(proto_entry: ProtoEntry) -> UnvalidatedProtoEntry {
......
......@@ -125,6 +125,13 @@ test_protover_parse_fail(void *arg)
/* Broken range */
elts = parse_protocol_list("Link=1,9-8,3");
tt_ptr_op(elts, OP_EQ, NULL);
/* Protocol name too long */
elts = parse_protocol_list("DoSaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
tt_ptr_op(elts, OP_EQ, NULL);
#endif
done:
;
......@@ -219,6 +226,15 @@ test_protover_vote(void *arg)
tt_str_op(result, OP_EQ, "");
tor_free(result);
/* Protocol name too long */
smartlist_clear(lst);
smartlist_add(lst, (void*) "DoSaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
result = protover_compute_vote(lst, 1);
tt_str_op(result, OP_EQ, "");
tor_free(result);
done:
tor_free(result);
smartlist_free(lst);
......@@ -300,6 +316,15 @@ test_protover_all_supported(void *arg)
tt_assert(protover_all_supported("Sleen=0-4294967295", &msg));
tor_end_capture_bugs_();
/* Protocol name too long */
tor_capture_bugs_(1);
tt_assert(protover_all_supported(
"DoSaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
"aaaaaaaaaaaa=1-65536", &msg));
tor_end_capture_bugs_();
done:
tor_end_capture_bugs_();
tor_free(msg);
......
......@@ -218,7 +218,7 @@
#define USING_TWOS_COMPLEMENT
/* Version number of package */
#define VERSION "0.3.3.5-rc-dev"
#define VERSION "0.3.3.6"
......