From: Stephan Bosch <stephan.bosch@open-xchange.com>
Date: Sun, 13 Oct 2019 16:49:28 +0000 (+0200)
Subject: lib-compression: istream-lz4 - Fix calling i_stream_read*() with a full buffer.
X-Git-Tag: 2.3.11.2~567
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3e7bc69d7945906c9d40eb23c6b4d85782f3ebd8;p=thirdparty%2Fdovecot%2Fcore.git

lib-compression: istream-lz4 - Fix calling i_stream_read*() with a full buffer.

Before, this read and discarded one chunk of the compressed parent stream data,
causing data corruption. Fixed by checking whether the buffer is full first.
---

diff --git a/src/lib-compression/istream-lz4.c b/src/lib-compression/istream-lz4.c
index cb5ca5cc74..b7100ec6e6 100644
--- a/src/lib-compression/istream-lz4.c
+++ b/src/lib-compression/istream-lz4.c
@@ -92,6 +92,10 @@ static ssize_t i_stream_lz4_read(struct istream_private *stream)
 	size_t size;
 	int ret;
 
+	/* if we already have max_buffer_size amount of data, fail here */
+	if (stream->pos - stream->skip >= i_stream_get_max_buffer_size(&stream->istream))
+		return -2;
+
 	if (!zstream->header_read) {
 		if ((ret = i_stream_lz4_read_header(zstream)) <= 0) {
 			stream->istream.eof = TRUE;
diff --git a/src/lib-compression/test-compression.c b/src/lib-compression/test-compression.c
index f62d7d6094..14db3b2586 100644
--- a/src/lib-compression/test-compression.c
+++ b/src/lib-compression/test-compression.c
@@ -94,6 +94,8 @@ static void test_compression_handler(const struct compression_handler *handler)
 		if (seeked)
 			break;
 		seeked = TRUE;
+		i_stream_seek(input, 1);
+		(void)i_stream_read(input);
 		i_stream_seek(input, 0);
 	}
 	i_stream_destroy(&input);