Merge pull request #6713 from geoffw0/cwe139

C++: New query for 'Cleartext transmission of sensitive information'
This commit is contained in:
Mathias Vorreiter Pedersen
2021-10-01 11:10:36 +02:00
committed by GitHub
10 changed files with 353 additions and 1 deletions

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@@ -0,0 +1,2 @@
lgtm,codescanning
* A new query (`cpp/cleartext-transmission`) has been added. This is similar to the `cpp/cleartext-storage-file`, `cpp/cleartext-storage-buffer` and `cpp/cleartext-storage-database` queries but looks for cases where sensitive information is most likely transmitted over a network.

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@@ -85,4 +85,6 @@ private class Recv extends AliasFunction, ArrayFunction, SideEffectFunction,
) and
description = "Buffer read by " + this.getName()
}
override predicate hasSocketInput(FunctionInput input) { input.isParameter(0) }
}

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@@ -60,4 +60,6 @@ private class Send extends AliasFunction, ArrayFunction, SideEffectFunction, Rem
override predicate hasRemoteFlowSink(FunctionInput input, string description) {
input.isParameterDeref(1) and description = "Buffer sent by " + this.getName()
}
override predicate hasSocketInput(FunctionInput input) { input.isParameter(0) }
}

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@@ -18,6 +18,12 @@ abstract class RemoteFlowSourceFunction extends Function {
* Holds if remote data described by `description` flows from `output` of a call to this function.
*/
abstract predicate hasRemoteFlowSource(FunctionOutput output, string description);
/**
* Holds if remote data from this source comes from a socket described by
* `input`. There is no result if a socket is not specified.
*/
predicate hasSocketInput(FunctionInput input) { none() }
}
/**
@@ -51,4 +57,10 @@ abstract class RemoteFlowSinkFunction extends Function {
* send over a network connection.
*/
abstract predicate hasRemoteFlowSink(FunctionInput input, string description);
/**
* Holds if data put into this sink is transmitted through a socket described
* by `input`. There is no result if a socket is not specified.
*/
predicate hasSocketInput(FunctionInput input) { none() }
}

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@@ -9,7 +9,7 @@ storage.</p>
</overview>
<recommendation>
<p>Ensure that sensitive information is always encrypted before being stored, especially before writing to a file.
<p>Ensure that sensitive information is always encrypted before being stored to a file or transmitted over the network.
It may be wise to encrypt information before it is put into a buffer that may be readable in memory.</p>
<p>In general, decrypt sensitive information only at the point where it is necessary for it to be used in

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@@ -0,0 +1,5 @@
<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>
<include src="CleartextStorage.inc.qhelp" /></qhelp>

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@@ -0,0 +1,124 @@
/**
* @name Cleartext transmission of sensitive information
* @description Transmitting sensitive information across a network in
* cleartext can expose it to an attacker.
* @kind path-problem
* @problem.severity warning
* @security-severity 7.5
* @precision medium
* @id cpp/cleartext-transmission
* @tags security
* external/cwe/cwe-319
*/
import cpp
import semmle.code.cpp.security.SensitiveExprs
import semmle.code.cpp.dataflow.TaintTracking
import semmle.code.cpp.models.interfaces.FlowSource
import DataFlow::PathGraph
/**
* A function call that sends or receives data over a network.
*/
abstract class NetworkSendRecv extends FunctionCall {
/**
* Gets the expression for the socket or similar object used for sending or
* receiving data (if any).
*/
abstract Expr getSocketExpr();
/**
* Gets the expression for the buffer to be sent from / received into.
*/
abstract Expr getDataExpr();
}
/**
* A function call that sends data over a network.
*
* note: functions such as `write` may be writing to a network source or a file. We could attempt to determine which, and sort results into `cpp/cleartext-transmission` and perhaps `cpp/cleartext-storage-file`. In practice it usually isn't very important which query reports a result as long as its reported exactly once.
*/
class NetworkSend extends NetworkSendRecv {
RemoteFlowSinkFunction target;
NetworkSend() { target = this.getTarget() }
override Expr getSocketExpr() {
exists(FunctionInput input, int arg |
target.hasSocketInput(input) and
input.isParameter(arg) and
result = this.getArgument(arg)
)
}
override Expr getDataExpr() {
exists(FunctionInput input, int arg |
target.hasRemoteFlowSink(input, _) and
input.isParameterDeref(arg) and
result = this.getArgument(arg)
)
}
}
/**
* A function call that receives data over a network.
*/
class NetworkRecv extends NetworkSendRecv {
RemoteFlowSourceFunction target;
NetworkRecv() { target = this.getTarget() }
override Expr getSocketExpr() {
exists(FunctionInput input, int arg |
target.hasSocketInput(input) and
input.isParameter(arg) and
result = this.getArgument(arg)
)
}
override Expr getDataExpr() {
exists(FunctionOutput output, int arg |
target.hasRemoteFlowSource(output, _) and
output.isParameterDeref(arg) and
result = this.getArgument(arg)
)
}
}
/**
* Taint flow from a sensitive expression to a network operation with data
* tainted by that expression.
*/
class SensitiveSendRecvConfiguration extends TaintTracking::Configuration {
SensitiveSendRecvConfiguration() { this = "SensitiveSendRecvConfiguration" }
override predicate isSource(DataFlow::Node source) { source.asExpr() instanceof SensitiveExpr }
override predicate isSink(DataFlow::Node sink) {
exists(NetworkSendRecv transmission |
sink.asExpr() = transmission.getDataExpr() and
// a zero socket descriptor is standard input, which is not interesting for this query.
not exists(Zero zero |
DataFlow::localFlow(DataFlow::exprNode(zero),
DataFlow::exprNode(transmission.getSocketExpr()))
)
)
}
}
from
SensitiveSendRecvConfiguration config, DataFlow::PathNode source, DataFlow::PathNode sink,
NetworkSendRecv transmission, string msg
where
config.hasFlowPath(source, sink) and
sink.getNode().asExpr() = transmission.getDataExpr() and
if transmission instanceof NetworkSend
then
msg =
"This operation transmits '" + sink.toString() +
"', which may contain unencrypted sensitive data from $@"
else
msg =
"This operation receives into '" + sink.toString() +
"', which may put unencrypted sensitive data into $@"
select transmission, source, sink, msg, source, source.getNode().asExpr().toString()

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@@ -0,0 +1,49 @@
edges
| test3.cpp:68:21:68:29 | password1 | test3.cpp:70:15:70:17 | ptr |
| test3.cpp:75:15:75:22 | password | test3.cpp:77:15:77:17 | ptr |
| test3.cpp:106:20:106:25 | buffer | test3.cpp:108:14:108:19 | buffer |
| test3.cpp:111:28:111:33 | buffer | test3.cpp:113:9:113:14 | buffer |
| test3.cpp:120:9:120:23 | global_password | test3.cpp:138:16:138:29 | call to get_global_str |
| test3.cpp:128:11:128:18 | password | test3.cpp:106:20:106:25 | buffer |
| test3.cpp:132:21:132:22 | call to id | test3.cpp:134:15:134:17 | ptr |
| test3.cpp:132:24:132:32 | password1 | test3.cpp:111:28:111:33 | buffer |
| test3.cpp:132:24:132:32 | password1 | test3.cpp:132:21:132:22 | call to id |
| test3.cpp:138:16:138:29 | call to get_global_str | test3.cpp:140:15:140:18 | data |
| test3.cpp:151:19:151:26 | password | test3.cpp:153:15:153:20 | buffer |
nodes
| test3.cpp:20:15:20:23 | password1 | semmle.label | password1 |
| test3.cpp:24:15:24:23 | password2 | semmle.label | password2 |
| test3.cpp:41:15:41:22 | password | semmle.label | password |
| test3.cpp:49:15:49:22 | password | semmle.label | password |
| test3.cpp:68:21:68:29 | password1 | semmle.label | password1 |
| test3.cpp:70:15:70:17 | ptr | semmle.label | ptr |
| test3.cpp:75:15:75:22 | password | semmle.label | password |
| test3.cpp:77:15:77:17 | ptr | semmle.label | ptr |
| test3.cpp:95:12:95:19 | password | semmle.label | password |
| test3.cpp:106:20:106:25 | buffer | semmle.label | buffer |
| test3.cpp:108:14:108:19 | buffer | semmle.label | buffer |
| test3.cpp:111:28:111:33 | buffer | semmle.label | buffer |
| test3.cpp:113:9:113:14 | buffer | semmle.label | buffer |
| test3.cpp:120:9:120:23 | global_password | semmle.label | global_password |
| test3.cpp:128:11:128:18 | password | semmle.label | password |
| test3.cpp:132:21:132:22 | call to id | semmle.label | call to id |
| test3.cpp:132:24:132:32 | password1 | semmle.label | password1 |
| test3.cpp:134:15:134:17 | ptr | semmle.label | ptr |
| test3.cpp:138:16:138:29 | call to get_global_str | semmle.label | call to get_global_str |
| test3.cpp:140:15:140:18 | data | semmle.label | data |
| test3.cpp:151:19:151:26 | password | semmle.label | password |
| test3.cpp:153:15:153:20 | buffer | semmle.label | buffer |
subpaths
| test3.cpp:132:24:132:32 | password1 | test3.cpp:111:28:111:33 | buffer | test3.cpp:113:9:113:14 | buffer | test3.cpp:132:21:132:22 | call to id |
#select
| test3.cpp:20:3:20:6 | call to send | test3.cpp:20:15:20:23 | password1 | test3.cpp:20:15:20:23 | password1 | This operation transmits 'password1', which may contain unencrypted sensitive data from $@ | test3.cpp:20:15:20:23 | password1 | password1 |
| test3.cpp:24:3:24:6 | call to send | test3.cpp:24:15:24:23 | password2 | test3.cpp:24:15:24:23 | password2 | This operation transmits 'password2', which may contain unencrypted sensitive data from $@ | test3.cpp:24:15:24:23 | password2 | password2 |
| test3.cpp:41:3:41:6 | call to recv | test3.cpp:41:15:41:22 | password | test3.cpp:41:15:41:22 | password | This operation receives into 'password', which may put unencrypted sensitive data into $@ | test3.cpp:41:15:41:22 | password | password |
| test3.cpp:49:3:49:6 | call to recv | test3.cpp:49:15:49:22 | password | test3.cpp:49:15:49:22 | password | This operation receives into 'password', which may put unencrypted sensitive data into $@ | test3.cpp:49:15:49:22 | password | password |
| test3.cpp:70:3:70:6 | call to send | test3.cpp:68:21:68:29 | password1 | test3.cpp:70:15:70:17 | ptr | This operation transmits 'ptr', which may contain unencrypted sensitive data from $@ | test3.cpp:68:21:68:29 | password1 | password1 |
| test3.cpp:77:3:77:6 | call to recv | test3.cpp:75:15:75:22 | password | test3.cpp:77:15:77:17 | ptr | This operation receives into 'ptr', which may put unencrypted sensitive data into $@ | test3.cpp:75:15:75:22 | password | password |
| test3.cpp:95:3:95:6 | call to read | test3.cpp:95:12:95:19 | password | test3.cpp:95:12:95:19 | password | This operation receives into 'password', which may put unencrypted sensitive data into $@ | test3.cpp:95:12:95:19 | password | password |
| test3.cpp:108:2:108:5 | call to recv | test3.cpp:128:11:128:18 | password | test3.cpp:108:14:108:19 | buffer | This operation receives into 'buffer', which may put unencrypted sensitive data into $@ | test3.cpp:128:11:128:18 | password | password |
| test3.cpp:134:3:134:6 | call to send | test3.cpp:132:24:132:32 | password1 | test3.cpp:134:15:134:17 | ptr | This operation transmits 'ptr', which may contain unencrypted sensitive data from $@ | test3.cpp:132:24:132:32 | password1 | password1 |
| test3.cpp:140:3:140:6 | call to send | test3.cpp:120:9:120:23 | global_password | test3.cpp:140:15:140:18 | data | This operation transmits 'data', which may contain unencrypted sensitive data from $@ | test3.cpp:120:9:120:23 | global_password | global_password |
| test3.cpp:153:3:153:6 | call to send | test3.cpp:151:19:151:26 | password | test3.cpp:153:15:153:20 | buffer | This operation transmits 'buffer', which may contain unencrypted sensitive data from $@ | test3.cpp:151:19:151:26 | password | password |

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@@ -0,0 +1 @@
Security/CWE/CWE-311/CleartextTransmission.ql

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@@ -0,0 +1,155 @@
typedef unsigned long size_t;
#define STDIN_FILENO (0)
size_t strlen(const char *s);
void send(int fd, const void *buf, size_t bufLen, int d);
void recv(int fd, void *buf, size_t bufLen, int d);
void read(int fd, void *buf, size_t bufLen);
void LogonUserA(int a, int b, const char *password, int d, int e, int f);
int val();
void test_send(const char *password1, const char *password2, const char *password_hash, const char *message)
{
{
LogonUserA(val(), val(), password1, val(), val(), val()); // proof `password1` is plaintext
send(val(), password1, strlen(password1), val()); // BAD: `password1` is sent plaintext (certainly)
}
{
send(val(), password2, strlen(password2), val()); // BAD: `password2` is sent plaintext (probably)
}
{
send(val(), password_hash, strlen(password_hash), val()); // GOOD: `password_hash` is sent encrypted
}
{
send(val(), message, strlen(message), val()); // GOOD: `message` is not a password
}
}
void test_receive()
{
{
char password[256];
recv(val(), password, 256, val()); // BAD: `password` is received plaintext (certainly)
LogonUserA(val(), val(), password, val(), val(), val()); // (proof `password` is plaintext)
}
{
char password[256];
recv(val(), password, 256, val()); // BAD: `password` is received plaintext (probably)
}
{
char password_hash[256];
recv(val(), password_hash, 256, val()); // GOOD: `password` is received encrypted
}
{
char message[256];
recv(val(), message, 256, val()); // GOOD: `message` is not a password
}
}
void test_dataflow(const char *password1)
{
{
const char *ptr = password1;
send(val(), ptr, strlen(ptr), val()); // BAD: `password` is sent plaintext
}
{
char password[256];
char *ptr = password;
recv(val(), ptr, 256, val()); // BAD: `password` is received plaintext
}
{
char buffer[256];
recv(val(), buffer, 256, val()); // BAD: `password` is received plaintext [NOT DETECTED]
char *password = buffer;
}
}
void test_read()
{
{
char password[256];
int fd = val();
read(fd, password, 256); // BAD: `password` is received plaintext
}
{
char password[256];
int fd = STDIN_FILENO;
read(fd, password, 256); // GOOD: `password` is received from stdin, not a network socket
}
}
void my_recv(char *buffer, size_t bufferSize)
{
recv(val(), buffer, bufferSize, val());
}
const char *id(const char *buffer)
{
return buffer;
}
char *global_password;
char *get_global_str()
{
return global_password;
}
void test_interprocedural(const char *password1)
{
{
char password[256];
my_recv(password, 256); // BAD: `password` is received plaintext [detected on line 108]
}
{
const char *ptr = id(password1);
send(val(), ptr, strlen(ptr), val()); // BAD: `password1` is sent plaintext
}
{
char *data = get_global_str();
send(val(), data, strlen(data), val()); // BAD: `global_password` is sent plaintext
}
}
char *strncpy(char *s1, const char *s2, size_t n);
void test_taint(const char *password)
{
{
char buffer[16];
strncpy(buffer, password, 16);
buffer[15] = 0;
send(val(), buffer, 16, val()); // BAD: `password` is (partially) sent plaintext
}
}