mapper: check for "." and ".."

Make map_directory_child_fs() refuse the names "." and "..". This is currently the interface where an attacker may inject a manipulated path (through the "update" command).

mapper: check for "." and ".."
f2918767 · Max Kellermann · a5f8d438 · f2918767
Commit f2918767 authored Oct 31, 2008 by Max Kellermann
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mapper.c src/mapper.c +5 -0

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--- a/src/mapper.c
+++ b/src/mapper.c
@@ -100,6 +100,11 @@ map_directory_child_fs(const struct directory *directory, const char *name,
 	char buffer2[MPD_PATH_MAX];
 	const char *parent_fs;
+	/* check for invalid or unauthorized base names */
+	if (*name == 0 || strchr(name, '/') != NULL ||
+	    strcmp(name, ".") == 0 || strcmp(name, "..") == 0)
+		return NULL;
 	parent_fs = map_directory_fs(directory, buffer2);
 	if (parent_fs == NULL)
 		return NULL;