From: Christopher J. Morrone Date: Thu, 26 Mar 2015 01:53:18 +0000 (-0400) Subject: staging/lustre/mdc: Handle empty but non-zero acl xattr X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=f42894004727ffdfb3b0826b0047eaf44cbdece6;p=openwrt%2Fstaging%2Fblogic.git staging/lustre/mdc: Handle empty but non-zero acl xattr We have found that posix_acl_access can have a value of \002\000\000\000. In that case body->aclsize is non-zero, but the there are no actuall acls stored in the xattr. In mdc_unpack_acl(), it only checks IS_ERR() on the pointer returned by posix_acl_from_xattr(), it does not check for NULL. Because of the above situation, the xattr aclsize can be non-zero, but posic_acl_from_xattr() still returns NULL. Passing NULL to posix_acl_valid() crashes the kernel. We add a check to properly handle the NULL return value. Signed-off-by: Christopher J. Morrone Reviewed-on: http://review.whamcloud.com/11989 Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5150 Reviewed-by: Fan Yong Reviewed-by: Bob Glossman Signed-off-by: Oleg Drokin Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/lustre/lustre/mdc/mdc_request.c b/drivers/staging/lustre/lustre/mdc/mdc_request.c index c04eec5c603e..f8ef5fe5e771 100644 --- a/drivers/staging/lustre/lustre/mdc/mdc_request.c +++ b/drivers/staging/lustre/lustre/mdc/mdc_request.c @@ -481,6 +481,9 @@ static int mdc_unpack_acl(struct ptlrpc_request *req, struct lustre_md *md) return -EPROTO; acl = posix_acl_from_xattr(&init_user_ns, buf, body->aclsize); + if (acl == NULL) + return 0; + if (IS_ERR(acl)) { rc = PTR_ERR(acl); CERROR("convert xattr to acl: %d\n", rc);