From: Alan T. DeKok <aland@freeradius.org>
Date: Tue, 30 Jan 2024 11:49:09 +0000 (-0500)
Subject: There may already be a packet in the buffer.  Helps with #5286
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a3f0e61d1d1790a9c5df126a322802bb2c6e7dd2;p=thirdparty%2Ffreeradius-server.git

There may already be a packet in the buffer.  Helps with #5286
---

diff --git a/src/listen/radius/proto_radius_tcp.c b/src/listen/radius/proto_radius_tcp.c
index 5d24641df42..48635a5dfff 100644
--- a/src/listen/radius/proto_radius_tcp.c
+++ b/src/listen/radius/proto_radius_tcp.c
@@ -108,6 +108,24 @@ static ssize_t mod_read(fr_listen_t *li, UNUSED void **packet_ctx, fr_time_t *re
 	size_t				packet_len, in_buffer;
 	decode_fail_t			reason;
 
+	/*
+	 *	We may hvae read multiple packets in the previous read.  In which case the buffer may already
+	 *	have packets remaining.  In that case, we can return packets directly from the buffer, and
+	 *	skip the read().
+	 */
+	if (*leftover >= RADIUS_HEADER_LENGTH) {
+		packet_len = fr_nbo_to_uint16(buffer + 2);
+
+		if (packet_len <= *leftover) {
+			data_size = 0;
+			goto have_packet;
+		}
+
+		/*
+		 *	Else we don't have a full packet, try to read more data from the network.
+		 */
+	}
+
 	/*
 	 *      Read data into the buffer.
 	 */
@@ -119,7 +137,7 @@ static ssize_t mod_read(fr_listen_t *li, UNUSED void **packet_ctx, fr_time_t *re
 #endif
 		case EAGAIN:
 			/*
-			 *	We didn't read any data leave the buffers alone.
+			 *	We didn't read any data; leave the buffers alone.
 			 *
 			 *	i.e. if we had a partial packet in the buffer and we didn't read any data,
 			 *	then the partial packet is still left in the buffer.
@@ -130,7 +148,7 @@ static ssize_t mod_read(fr_listen_t *li, UNUSED void **packet_ctx, fr_time_t *re
 			break;
 		}
 
-		PDEBUG2("proto_radius_tcp got read error %zd", data_size);
+		PDEBUG2("proto_radius_tcp got read error (%zd) - %s", data_size, fr_syserror(errno));
 		return data_size;
 	}
 
@@ -148,6 +166,7 @@ static ssize_t mod_read(fr_listen_t *li, UNUSED void **packet_ctx, fr_time_t *re
 		return -1;
 	}
 
+have_packet:
 	/*
 	 *	We MUST always start with a known RADIUS packet.
 	 */
@@ -162,7 +181,7 @@ static ssize_t mod_read(fr_listen_t *li, UNUSED void **packet_ctx, fr_time_t *re
 	/*
 	 *	Not enough for one packet.  Tell the caller that we need to read more.
 	 */
-	if (in_buffer < 20) {
+	if (in_buffer < RADIUS_HEADER_LENGTH) {
 		*leftover = in_buffer;
 		return 0;
 	}
diff --git a/src/listen/tacacs/proto_tacacs_tcp.c b/src/listen/tacacs/proto_tacacs_tcp.c
index 19d58c3892d..71a327a5273 100644
--- a/src/listen/tacacs/proto_tacacs_tcp.c
+++ b/src/listen/tacacs/proto_tacacs_tcp.c
@@ -130,6 +130,25 @@ static ssize_t mod_read(fr_listen_t *li, UNUSED void **packet_ctx, fr_time_t *re
 	ssize_t				data_size, packet_len;
 	size_t				in_buffer;
 
+	/*
+	 *	We may hvae read multiple packets in the previous read.  In which case the buffer may already
+	 *	have packets remaining.  In that case, we can return packets directly from the buffer, and
+	 *	skip the read().
+	 */
+	if (*leftover >= FR_HEADER_LENGTH) {
+		packet_len = fr_tacacs_length(buffer, *leftover);
+		if (packet_len < 0) goto invalid;
+
+		if (packet_len <= *leftover) {
+			data_size = 0;
+			goto have_packet;
+		}
+
+		/*
+		 *	Else we don't have a full packet, try to read more data from the network.
+		 */
+	}
+
 	/*
 	 *      Read data into the buffer.
 	 */
@@ -170,6 +189,7 @@ static ssize_t mod_read(fr_listen_t *li, UNUSED void **packet_ctx, fr_time_t *re
 		return -1;
 	}
 
+have_packet:
 	/*
 	 *	Represents all the data we've read since we last
 	 *	decoded a complete packet.
@@ -183,6 +203,7 @@ static ssize_t mod_read(fr_listen_t *li, UNUSED void **packet_ctx, fr_time_t *re
 	 */
 	packet_len = fr_tacacs_length(buffer, in_buffer);
 	if (packet_len < 0) {
+	invalid:
 		PERROR("Invalid TACACS packet");
 		return -1;	/* Malformed, close the socket */
 	}