From: Keith Mannthey <keith.mannthey@intel.com>
Date: Tue, 18 Jun 2013 16:36:31 +0000 (-0700)
Subject: LU-3403 llite: error of listxattr when buffer is small
X-Git-Tag: 2.4.52~31
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=refs%2Fchanges%2F63%2F6463%2F8;p=fs%2Flustre-release.git

LU-3403 llite: error of listxattr when buffer is small

According to the standard, listxattr(2) should return -1
and errno should be set to ERANGE if the size of the list
buffer is too small to hold the result. However ll_listxattr()
will return a value bigger than the size of buffer in some cases.

Let's assume listxattr(2) returns SIZE when it is called with a
large enough list buffer. If it's called again with a list buffer
whose size is smaller than SIZE but bigger than (SIZE - 12), then
listxattr(2) will return SIZE too. This patch fixes the problem.
Original patch by Li Xi <pkuelelixi@gmail.com>

Signed-off-by: Keith Mannthey <keith.mannthey@intel.com>
Change-Id: Ifb29ae900a5ee57dfde8781f7a008b6129c7bf91
Reviewed-on: http://review.whamcloud.com/6463
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Li Xi <pkuelelixi@gmail.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/llite/xattr.c b/lustre/llite/xattr.c
index a08c58a..0f2e189 100644
--- a/lustre/llite/xattr.c
+++ b/lustre/llite/xattr.c
@@ -564,7 +564,12 @@ ssize_t ll_listxattr(struct dentry *dentry, char *buffer, size_t size)
                 const size_t name_len   = sizeof("lov") - 1;
                 const size_t total_len  = prefix_len + name_len + 1;
 
-		if (buffer && (rc + total_len) <= size) {
+		if (((rc + total_len) > size) && (buffer != NULL)) {
+			ptlrpc_req_finished(request);
+			return -ERANGE;
+		}
+
+		if (buffer != NULL) {
 			buffer += rc;
 			memcpy(buffer, XATTR_LUSTRE_PREFIX, prefix_len);
 			memcpy(buffer + prefix_len, "lov", name_len);