From 5a7d3caf9cc4edace0176661102656adbf22f7be Mon Sep 17 00:00:00 2001
From: Robby Zambito <contact@robbyzambito.me>
Date: Fri, 2 Jan 2026 23:51:49 +0000
Subject: Subject validation

---
 src/server/message_parser.zig | 59 +++++++++++++++++++++++++++++++------------
 1 file changed, 43 insertions(+), 16 deletions(-)

(limited to 'src/server/message_parser.zig')

diff --git a/src/server/message_parser.zig b/src/server/message_parser.zig
index 381dc2c..0d60df5 100644
--- a/src/server/message_parser.zig
+++ b/src/server/message_parser.zig
@@ -294,7 +294,7 @@ pub const Message = union(enum) {
                     @branchHint(.unlikely);
                     return error.InvalidStream;
                 }
-                const subject = try readSubject(alloc, in);
+                const subject = try readSubject(alloc, in, .sub);
                 errdefer alloc.free(subject);
                 const second = blk: {
                     // Drop whitespace
@@ -392,7 +392,7 @@ fn parsePub(alloc: std.mem.Allocator, in: *std.Io.Reader) !Message {
     try in.discardAll(1); // throw away space
 
     // Parse subject
-    const subject: []const u8 = try readSubject(alloc, in);
+    const subject: []const u8 = try readSubject(alloc, in, .@"pub");
     errdefer alloc.free(subject);
 
     const States = enum {
@@ -526,7 +526,7 @@ fn parseHPub(alloc: std.mem.Allocator, in: *std.Io.Reader) !Message {
     try in.discardAll(1); // throw away space
 
     // Parse subject
-    const subject: []const u8 = try readSubject(alloc, in);
+    const subject: []const u8 = try readSubject(alloc, in, .@"pub");
     errdefer alloc.free(subject);
 
     const States = enum {
@@ -699,30 +699,57 @@ test parseHPub {
     }
 }
 
-fn readSubject(alloc: std.mem.Allocator, in: *std.Io.Reader) ![]const u8 {
+fn readSubject(alloc: std.mem.Allocator, in: *std.Io.Reader, comptime pub_or_sub: enum { @"pub", sub }) ![]const u8 {
     var subject_list: std.ArrayList(u8) = .empty;
     errdefer subject_list.deinit(alloc);
 
     // Handle the first character
     {
         const byte = try in.takeByte();
-        if (std.ascii.isWhitespace(byte) or byte == '.')
+        if (std.ascii.isWhitespace(byte) or byte == '.' or (pub_or_sub == .@"pub" and (byte == '*' or byte == '>')))
             return error.InvalidStream;
 
         try subject_list.append(alloc, byte);
     }
 
-    while (in.takeByte()) |byte| {
-        if (std.ascii.isWhitespace(byte)) break;
-        if (std.ascii.isAscii(byte)) {
-            if (byte == '.') {
-                const next_byte = try in.peekByte();
-                if (next_byte == '.' or std.ascii.isWhitespace(next_byte))
-                    return error.InvalidSubject;
-            }
-            try subject_list.append(alloc, byte);
-        }
-    } else |err| return err;
+    switch (pub_or_sub) {
+        .sub => {
+            while (in.takeByte()) |byte| {
+                if (std.ascii.isWhitespace(byte)) break;
+                if (std.ascii.isAscii(byte)) {
+                    if (byte == '.') {
+                        const next_byte = try in.peekByte();
+                        if (next_byte == '.' or std.ascii.isWhitespace(next_byte))
+                            return error.InvalidStream;
+                    } else if (byte == '>') {
+                        const next_byte = try in.takeByte();
+                        if (!std.ascii.isWhitespace(next_byte))
+                            return error.InvalidStream;
+                    } else if (byte == '*') {
+                        const next_byte = try in.peekByte();
+                        if (next_byte != '.' and !std.ascii.isWhitespace(next_byte))
+                            return error.InvalidStream;
+                    }
+                    try subject_list.append(alloc, byte);
+                }
+            } else |err| return err;
+        },
+        .@"pub" => {
+            while (in.takeByte()) |byte| {
+                if (std.ascii.isWhitespace(byte)) break;
+                if (std.ascii.isAscii(byte)) {
+                    if (byte == '*' or byte == '>') return error.InvalidStream;
+                    if (byte == '.') {
+                        const next_byte = try in.peekByte();
+                        if (next_byte == '.' or std.ascii.isWhitespace(next_byte))
+                            return error.InvalidStream;
+                    }
+                    try subject_list.append(alloc, byte);
+                }
+            } else |err| return err;
+        },
+    }
+
     return subject_list.toOwnedSlice(alloc);
 }
 
-- 
cgit