diff options
Diffstat (limited to 'services/net')
| -rw-r--r-- | services/net/java/android/net/dhcp/DhcpPacket.java | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/services/net/java/android/net/dhcp/DhcpPacket.java b/services/net/java/android/net/dhcp/DhcpPacket.java index a232a6e..d41629d 100644 --- a/services/net/java/android/net/dhcp/DhcpPacket.java +++ b/services/net/java/android/net/dhcp/DhcpPacket.java @@ -611,10 +611,22 @@ abstract class DhcpPacket { /** * Reads a string of specified length from the buffer. */ - private static String readAsciiString(ByteBuffer buf, int byteCount) { + private static String readAsciiString(ByteBuffer buf, int byteCount, boolean nullOk) { byte[] bytes = new byte[byteCount]; buf.get(bytes); - return new String(bytes, 0, bytes.length, StandardCharsets.US_ASCII); + int length = bytes.length; + if (!nullOk) { + // Stop at the first null byte. This is because some DHCP options (e.g., the domain + // name) are passed to netd via FrameworkListener, which refuses arguments containing + // null bytes. We don't do this by default because vendorInfo is an opaque string which + // could in theory contain null bytes. + for (length = 0; length < bytes.length; length++) { + if (bytes[length] == 0) { + break; + } + } + } + return new String(bytes, 0, length, StandardCharsets.US_ASCII); } /** @@ -797,7 +809,7 @@ abstract class DhcpPacket { break; case DHCP_HOST_NAME: expectedLen = optionLen; - hostName = readAsciiString(packet, optionLen); + hostName = readAsciiString(packet, optionLen, false); break; case DHCP_MTU: expectedLen = 2; @@ -805,7 +817,7 @@ abstract class DhcpPacket { break; case DHCP_DOMAIN_NAME: expectedLen = optionLen; - domainName = readAsciiString(packet, optionLen); + domainName = readAsciiString(packet, optionLen, false); break; case DHCP_BROADCAST_ADDRESS: bcAddr = readIpAddress(packet); @@ -834,7 +846,7 @@ abstract class DhcpPacket { break; case DHCP_MESSAGE: expectedLen = optionLen; - message = readAsciiString(packet, optionLen); + message = readAsciiString(packet, optionLen, false); break; case DHCP_MAX_MESSAGE_SIZE: expectedLen = 2; @@ -850,7 +862,7 @@ abstract class DhcpPacket { break; case DHCP_VENDOR_CLASS_ID: expectedLen = optionLen; - vendorId = readAsciiString(packet, optionLen); + vendorId = readAsciiString(packet, optionLen, true); break; case DHCP_CLIENT_IDENTIFIER: { // Client identifier byte[] id = new byte[optionLen]; |