dovecot-2.2: dbox: Added asserts to dbox file fixing to make sur...

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.2/rev/03520d887a4f
changeset: 17483:03520d887a4f
user:      Timo Sirainen <tss at iki.fi>
date:      Fri Jun 13 03:09:26 2014 +0300
description:
dbox: Added asserts to dbox file fixing to make sure it doesn't go to infinite loop.
There apparently is a bug in here that will trigger this assert.

diffstat:

 src/lib-storage/index/dbox-common/dbox-file-fix.c |  13 +++++++++----
 1 files changed, 9 insertions(+), 4 deletions(-)

diffs (32 lines):

diff -r 53742463a9fe -r 03520d887a4f src/lib-storage/index/dbox-common/dbox-file-fix.c
--- a/src/lib-storage/index/dbox-common/dbox-file-fix.c	Fri Jun 13 02:54:21 2014 +0300
+++ b/src/lib-storage/index/dbox-common/dbox-file-fix.c	Fri Jun 13 03:09:26 2014 +0300
@@ -140,19 +140,24 @@
 	   magic markers. */
 
 	struct istream *input = file->input;
-	uoff_t orig_offset, pre_offset, post_offset;
+	uoff_t orig_offset, pre_offset, post_offset, prev_offset;
 	const unsigned char *data, *magic;
-	size_t size, need_bytes;
+	size_t size, need_bytes, prev_need_bytes;
 	int ret, match;
 
 	*pre_r = FALSE;
 
-	orig_offset = input->v_offset;
-	need_bytes = strlen(DBOX_MAGIC_POST);
+	orig_offset = prev_offset = input->v_offset;
+	need_bytes = strlen(DBOX_MAGIC_POST); prev_need_bytes = 0;
 	while ((ret = i_stream_read_data(input, &data, &size, need_bytes-1)) > 0 ||
 	       ret == -2) {
 		/* search for the beginning of a potential pre/post magic */
 		i_assert(size > 1);
+		i_assert(prev_offset != input->v_offset ||
+			 need_bytes > prev_need_bytes);
+		prev_offset = input->v_offset;
+		prev_need_bytes = need_bytes;
+
 		magic = memchr(data, DBOX_MAGIC_PRE[0], size);
 		if (magic == NULL) {
 			i_stream_skip(input, size-1);