[PATCH v4 01/22] receive-pack: do not overallocate command structure

[Junio C Hamano <gitster@pobox.com>]

An "update" command in the protocol exchange consists of 40-hex old
object name, SP, 40-hex new object name, SP, and a refname, but the
first instance is further followed by a NUL with feature requests.

The command structure, which has a flex-array member that stores the
refname at the end, was allocated based on the whole length of the
update command, without excluding the trailing feature requests.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/receive-pack.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index f93ac45..1663beb 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -872,10 +872,11 @@ static struct command *read_head_info(struct sha1_array *shallow)
 			if (parse_feature_request(feature_list, "quiet"))
 				quiet = 1;
 		}
-		cmd = xcalloc(1, sizeof(struct command) + len - 80);
+		cmd = xcalloc(1, sizeof(struct command) + reflen + 1);
 		hashcpy(cmd->old_sha1, old_sha1);
 		hashcpy(cmd->new_sha1, new_sha1);
-		memcpy(cmd->ref_name, line + 82, len - 81);
+		memcpy(cmd->ref_name, refname, reflen);
+		cmd->ref_name[reflen] = '\0';
 		*p = cmd;
 		p = &cmd->next;
 	}
-- 
2.1.0-399-g2df620b