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 c3999b5d83883637be881352e9359a898b7fbcee..86ded59b346ab6984ca4594826d4d9f5716cb5d4 100644 (file)
--- 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();
+       }
 }