From: Timo Sirainen <timo.sirainen@dovecot.fi>
Date: Wed, 16 Dec 2015 13:06:52 +0000 (+0200)
Subject: lib-compress: lz4 istream wasn't detected reliably in some situations.
X-Git-Tag: 2.2.22.rc1~401
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=879dfd4da1a9a379936b8d51c1e00c3bd77873b4;p=thirdparty%2Fdovecot%2Fcore.git

lib-compress: lz4 istream wasn't detected reliably in some situations.

We requested too few bytes from istream, so there wasn't any guarantee that
the istream actually had all the bytes. This caused a problem for example
with mdbox when the previous mail was already fetched and the stream happened
to end in the middle of the lz4 header.
---

diff --git a/src/lib-compression/compression.c b/src/lib-compression/compression.c
index c0c13a26db..e79a0f84fb 100644
--- a/src/lib-compression/compression.c
+++ b/src/lib-compression/compression.c
@@ -73,7 +73,8 @@ static bool is_compressed_lz4(struct istream *input)
 	const unsigned char *data;
 	size_t size;
 
-	if (i_stream_read_data(input, &data, &size, 6 - 1) <= 0)
+	if (i_stream_read_data(input, &data, &size,
+			       IOSTREAM_LZ4_MAGIC_LEN - 1) <= 0)
 		return FALSE;
 	/* there is no standard LZ4 header, so we've created our own */
 	return memcmp(data, IOSTREAM_LZ4_MAGIC, IOSTREAM_LZ4_MAGIC_LEN) == 0;