[PATCH] parse_tag_buffer(): avoid out of bound access

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

There is a check (size < 64) at the beginning of the function, but
that only covers object+type lines. Code for parsing "tag" and
"tagger" may access outside buffer. Fix it.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 On Thu, Feb 17, 2011 at 7:43 PM, René Scharfe <rene.scharfe@lsrfire.ath.cx> wrote:
 > memchr() won't notice if a negative value has been passed as third parameter
 > because its type is size_t, which is unsigned.  Negative values are
 > converted to big positive ones..

 I did not notice that. Fixed commit message.

 tag.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/tag.c b/tag.c
index ecf7c1e..7d38cc0 100644
--- a/tag.c
+++ b/tag.c
@@ -97,7 +97,9 @@ int parse_tag_buffer(struct tag *item, const void *data, unsigned long size)
 		item->tagged = NULL;
 	}
 
-	if (prefixcmp(bufptr, "tag "))
+	if (bufptr + 4 < tail && !prefixcmp(bufptr, "tag "))
+		; 		/* good */
+	else
 		return -1;
 	bufptr += 4;
 	nl = memchr(bufptr, '\n', tail - bufptr);
@@ -106,7 +108,7 @@ int parse_tag_buffer(struct tag *item, const void *data, unsigned long size)
 	item->tag = xmemdupz(bufptr, nl - bufptr);
 	bufptr = nl + 1;
 
-	if (!prefixcmp(bufptr, "tagger "))
+	if (bufptr + 7 < tail && !prefixcmp(bufptr, "tagger "))
 		item->date = parse_tag_date(bufptr, tail);
 	else
 		item->date = 0;
-- 
1.7.4.74.g639db