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From: Stefan Beller <stefanbeller@googlemail.com>
To: philipoakley@iee.org, peff@peff.net, j.sixt@viscovery.net,
	ramsay@ramsay1.demon.co.uk, gitster@pobox.com,
	git@vger.kernel.org
Cc: Stefan Beller <stefanbeller@googlemail.com>
Subject: [PATCH] parse_object_buffer: Correct freeing the buffer.
Date: Thu, 18 Jul 2013 00:09:42 +0200	[thread overview]
Message-ID: <1374098982-6962-1-git-send-email-stefanbeller@googlemail.com> (raw)
In-Reply-To: <51E715D8.9040307@googlemail.com>

If we exit early in the function parse_object_buffer, we did not
write to *eaten_p. Then the calling function parse_object, which looks
like the following with respect to the eaten variable, cannot rely on a
proper value set in eaten, hence the freeing of the buffer depends
on random values in memory.

	struct object *parse_object(const unsigned char *sha1)
	{
		int eaten;
		...
		obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
		if (!eaten)
			free(buffer);
	}

This change makes sure, the buffer freeing condition is deterministic.

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
---
 object.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/object.c b/object.c
index cbc7333..d8a4b1f 100644
--- a/object.c
+++ b/object.c
@@ -145,7 +145,7 @@ struct object *lookup_unknown_object(const unsigned char *sha1)
 struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
 {
 	struct object *obj;
-	int eaten = 0;
+	*eaten_p = 0;
 
 	obj = NULL;
 	if (type == OBJ_BLOB) {
@@ -164,7 +164,7 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t
 			if (!tree->object.parsed) {
 				if (parse_tree_buffer(tree, buffer, size))
 					return NULL;
-				eaten = 1;
+				*eaten_p = 1;
 			}
 		}
 	} else if (type == OBJ_COMMIT) {
@@ -174,7 +174,7 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t
 				return NULL;
 			if (!commit->buffer) {
 				commit->buffer = buffer;
-				eaten = 1;
+				*eaten_p = 1;
 			}
 			obj = &commit->object;
 		}
@@ -191,7 +191,6 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t
 	}
 	if (obj && obj->type == OBJ_NONE)
 		obj->type = type;
-	*eaten_p = eaten;
 	return obj;
 }
 
-- 
1.8.3.3.754.g9c3c367.dirty

  reply	other threads:[~2013-07-17 22:09 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-15 17:31 [PATCH] Fix some sparse warnings Ramsay Jones
2013-07-16  5:57 ` Johannes Sixt
2013-07-16  6:21   ` Jeff King
2013-07-16 20:53     ` Philip Oakley
2013-07-16 21:18       ` Stefan Beller
2013-07-16 22:18         ` Philip Oakley
2013-07-17  5:47         ` Johannes Sixt
2013-07-17 22:08       ` Stefan Beller
2013-07-17 22:09         ` Stefan Beller [this message]
2013-07-17 22:16         ` Stefan Beller
2013-07-17 23:22         ` Junio C Hamano
2013-07-18 17:58     ` Ramsay Jones

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