[PATCH v23 10/22] posix_acl: Improve xattr fixup code

Andreas Gruenbacher
2016-06-30T13:59:07Z

Both XATTR_NAME_POSIX_ACL_ACCESS and XATTR_NAME_POSIX_ACL_DEFAULT have
the same XATTR_SYSTEM_PREFIX prefix; don't check for the same prefix
repeatedly.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Steve French <steve.french@primarydata.com>
---
fs/xattr.c | 29 +++++++++++++++++++++++------
1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 4beafc4..61ac218 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -295,6 +295,16 @@ out:
}
EXPORT_SYMBOL_GPL(vfs_removexattr);

+static void
+fix_xattr_from_user(const char *kname, void *kvalue, size_t size)
+{
+ if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return;
+ kname += XATTR_SYSTEM_PREFIX_LEN;
+ if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
+ !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
+ posix_acl_fix_xattr_from_user(kvalue, size);
+}

/*
* Extended attribute SET operations
@@ -329,9 +339,7 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
error = -EFAULT;
goto out;
}
- if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
- (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
- posix_acl_fix_xattr_from_user(kvalue, size);
+ fix_xattr_from_user(kname, kvalue, size);
}

error = vfs_setxattr(d, kname, kvalue, size, flags);
@@ -396,6 +404,17 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
return error;
}

+static void
+fix_xattr_to_user(const char *kname, void *kvalue, size_t size)
+{
+ if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return;
+ kname += XATTR_SYSTEM_PREFIX_LEN;
+ if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
+ !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
+ posix_acl_fix_xattr_to_user(kvalue, size);
+}
+
/*
* Extended attribute GET operations
*/
@@ -426,9 +445,7 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,

error = vfs_getxattr(d, kname, kvalue, size);
if (error > 0) {
- if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
- (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
- posix_acl_fix_xattr_to_user(kvalue, size);
+ fix_xattr_to_user(kname, kvalue, size);
if (size && copy_to_user(value, kvalue, error))
error = -EFAULT;
} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
--
2.5.5