From: Arran Cudbard-Bell <a.cudbardb@freeradius.org>
Date: Sun, 11 Jan 2026 10:16:38 +0000 (+0000)
Subject: internal-decode: Allow decoding of empty groups (groups with no children)
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0fd420e195f42b2b67d7b69e1a7b3df490a94e43;p=thirdparty%2Ffreeradius-server.git

internal-decode: Allow decoding of empty groups (groups with no children)
---

diff --git a/src/protocols/internal/decode.c b/src/protocols/internal/decode.c
index c76edc7c63c..9d6324ea0a8 100644
--- a/src/protocols/internal/decode.c
+++ b/src/protocols/internal/decode.c
@@ -121,7 +121,7 @@ static ssize_t internal_decode_pair(TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dic
 	 *                           field (allows for future extensions).
 	 *
 	 * 0                   1                   2                   3
-	 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1kk
+	 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 	 * |tlen |llen |t|e|   Type (min)  |  Length (min) | value...
 	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -253,8 +253,13 @@ static ssize_t internal_decode_pair(TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dic
 				return fr_pair_decode_slen(slen, fr_dbuff_start(&work_dbuff), fr_dbuff_current(&work_dbuff));
 			}
 		}
+		/*
+		 *	It's ok for this function to return 0
+		 *	we can have empty groups (i.e. groups
+		 *	with no children)
+		 */
 		slen = internal_decode_structural(ctx, out, da, &work_dbuff, decode_ctx);
-		if (slen <= 0) goto error;
+		if (slen < 0) goto error;
 		break;
 
 	default:
diff --git a/src/tests/unit/protocols/internal/decode.txt b/src/tests/unit/protocols/internal/decode.txt
index 47cde44754d..0acf2827e31 100644
--- a/src/tests/unit/protocols/internal/decode.txt
+++ b/src/tests/unit/protocols/internal/decode.txt
@@ -37,6 +37,10 @@ match User-Name = "0123456789012345678901234567890123456789012345678901234567890
 returned
 match 304
 
+# Decode an empty grouping attribute (this is a regression test)
+decode-pair 00 1a 04 20 2c 50 00
+match Vendor-Specific = { FreeRADIUS = { } }
+
 #
 #  Edge cases
 #
@@ -77,4 +81,4 @@ match -2
 #
 
 count
-match 40
+match 42