From: Teemu Huovila <teemu.huovila@dovecot.fi>
Date: Tue, 4 Feb 2014 23:17:35 +0000 (-0500)
Subject: lib-compression: Add assert for LZ4_compress return value.
X-Git-Tag: 2.2.11~10
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=efd203f312659a7ce82644fb2a39d791ac198b77;p=thirdparty%2Fdovecot%2Fcore.git

lib-compression: Add assert for LZ4_compress return value.
Make certain we detect if compressed data overflows the allocated space.
---

diff --git a/src/lib-compression/ostream-lz4.c b/src/lib-compression/ostream-lz4.c
index 81ac0981f4..637245f7e0 100644
--- a/src/lib-compression/ostream-lz4.c
+++ b/src/lib-compression/ostream-lz4.c
@@ -18,7 +18,8 @@ struct lz4_ostream {
 	unsigned int compressbuf_offset;
 
 	/* chunk size, followed by compressed data */
-	unsigned char outbuf[IOSTREAM_LZ4_CHUNK_PREFIX_LEN + LZ4_COMPRESSBOUND(CHUNK_SIZE)];
+	unsigned char outbuf[IOSTREAM_LZ4_CHUNK_PREFIX_LEN +
+	                     LZ4_COMPRESSBOUND(CHUNK_SIZE)];
 	unsigned int outbuf_offset, outbuf_used;
 };
 
@@ -70,11 +71,13 @@ static int o_stream_lz4_compress(struct lz4_ostream *zstream)
 	i_assert(zstream->outbuf_offset == 0);
 	i_assert(zstream->outbuf_used == 0);
 
-	zstream->outbuf_used = IOSTREAM_LZ4_CHUNK_PREFIX_LEN +
-		LZ4_compress((void *)zstream->compressbuf,
-			     (void *)(zstream->outbuf + IOSTREAM_LZ4_CHUNK_PREFIX_LEN),
-			     zstream->compressbuf_offset);
-	i_assert(zstream->outbuf_used > IOSTREAM_LZ4_CHUNK_PREFIX_LEN);
+	ret = LZ4_compress((void *)zstream->compressbuf,
+			   (void *)(zstream->outbuf +
+			            IOSTREAM_LZ4_CHUNK_PREFIX_LEN),
+			   zstream->compressbuf_offset);
+	i_assert(ret > 0 && (unsigned int)ret <= sizeof(zstream->outbuf) -
+	         IOSTREAM_LZ4_CHUNK_PREFIX_LEN);
+	zstream->outbuf_used = IOSTREAM_LZ4_CHUNK_PREFIX_LEN + ret;
 	chunk_size = zstream->outbuf_used - IOSTREAM_LZ4_CHUNK_PREFIX_LEN;
 	zstream->outbuf[0] = (chunk_size & 0xff000000) >> 24;
 	zstream->outbuf[1] = (chunk_size & 0x00ff0000) >> 16;