From: Alexandre Montplaisir <alexmonthy@efficios.com>
Date: Thu, 19 May 2016 21:55:02 +0000 (-0400)
Subject: Restrict Java context retriever names to a set of valid characters
X-Git-Tag: v2.8.0~3
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=14ba880b03565b199d55671b3c6e476e2373d19e;p=lttng-ust.git

Restrict Java context retriever names to a set of valid characters

Since the context/retriever names end up as-is as part of the
metadata, only alphanumerical characters, periods "." and
underscores "_" should be accepted. The names must also not
start with a number.

Refuse registration of retriever names that do not respect these
conditions, so that the problem is reported right away to the
application.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/context/ContextInfoManager.java b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/context/ContextInfoManager.java
index c3999b5d..86ded59b 100644
--- a/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/context/ContextInfoManager.java
+++ b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/context/ContextInfoManager.java
@@ -21,6 +21,8 @@ import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * The singleton manager of {@link IContextInfoRetriever} objects.
@@ -31,6 +33,8 @@ public final class ContextInfoManager {
 
 	private static final String SHARED_LIBRARY_NAME = "lttng-ust-context-jni";
 
+	private static final Pattern VALID_CONTEXT_NAME_PATTERN = Pattern.compile("^[a-zA-Z0-9_\\.]+$");
+
 	private static ContextInfoManager instance;
 
 	private final Map<String, IContextInfoRetriever> contextInfoRetrievers = new ConcurrentHashMap<String, IContextInfoRetriever>();
@@ -95,6 +99,10 @@ public final class ContextInfoManager {
 	 */
 	public boolean registerContextInfoRetriever(String retrieverName, IContextInfoRetriever contextInfoRetriever) {
 		synchronized (retrieverLock) {
+			if (!validateRetrieverName(retrieverName)) {
+				return false;
+			}
+
 			if (contextInfoRetrievers.containsKey(retrieverName)) {
 				/*
 				 * There is already a retriever registered with that name,
@@ -157,4 +165,24 @@ public final class ContextInfoManager {
 	public IContextInfoRetriever getContextInfoRetriever(String retrieverName) {
 		return contextInfoRetrievers.get(retrieverName);
 	}
+
+	/**
+	 * Validate that the given retriever name contains only the allowed
+	 * characters, which are alphanumerical characters, period "." and
+	 * underscore "_". The name must also not start with a number.
+	 */
+	private static boolean validateRetrieverName(String contextName) {
+		if (contextName.isEmpty()) {
+			return false;
+		}
+
+		/* First character must not be a number */
+		if (Character.isDigit(contextName.charAt(0))) {
+			return false;
+		}
+
+		/* Validate the other characters of the string */
+		Matcher matcher = VALID_CONTEXT_NAME_PATTERN.matcher(contextName);
+		return matcher.matches();
+	}
 }