From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Tue, 30 May 2023 08:10:39 +0000 (+0300)
Subject: imap: Fix crash when trying to use COMPRESS multiple times
X-Git-Tag: 2.4.0~2725
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f9128b0757b2a73dd76aea8cde82a12f82c46cec;p=thirdparty%2Fdovecot%2Fcore.git

imap: Fix crash when trying to use COMPRESS multiple times

Broken by 5f27e25c64555dcaae6cb00c479cd05bc2638081

Fixes:
Panic: file cmd-compress.c: line 104 (cmd_compress): assertion failed: (client->input->v_offset == prev_in_offset)
---

diff --git a/src/imap/cmd-compress.c b/src/imap/cmd-compress.c
index 00fb36ff48..52c74b5a82 100644
--- a/src/imap/cmd-compress.c
+++ b/src/imap/cmd-compress.c
@@ -59,6 +59,12 @@ bool cmd_compress(struct client_command_context *cmd)
 		return TRUE;
 	}
 
+	if (client->compress_handler != NULL) {
+		client_send_tagline(cmd, t_strdup_printf(
+			"NO [COMPRESSIONACTIVE] COMPRESSION=%s already enabled.",
+			t_str_ucase(client->compress_handler->name)));
+		return TRUE;
+	}
 	int ret = compression_lookup_handler(t_str_lcase(mechanism), &handler);
 	if (ret <= 0) {
 		const char * tagline =
@@ -121,5 +127,6 @@ bool cmd_compress(struct client_command_context *cmd)
 	}
 
 	client_update_imap_parser_streams(client);
+	client->compress_handler = handler;
 	return TRUE;
 }
diff --git a/src/imap/imap-client.h b/src/imap/imap-client.h
index ad1e6f5c5d..194d7aa059 100644
--- a/src/imap/imap-client.h
+++ b/src/imap/imap-client.h
@@ -212,6 +212,8 @@ struct client {
 	/* NOTIFY extension */
 	struct imap_notify_context *notify_ctx;
 	uint32_t notify_uidnext;
+	/* COMPRESS extension */
+	const struct compression_handler *compress_handler;
 
 	/* client input/output is locked by this command */
 	struct client_command_context *input_lock;