8:59 a.m.
See comment in code for justification.
Thanks: Yongkui Guo for finding the bug.
---
daemon/xattr.c | 43 ++++++++++++++++++++++++++++++++++++++++---
1 file changed, 40 insertions(+), 3 deletions(-)
diff --git a/daemon/xattr.c b/daemon/xattr.c
index 761f6074b..3257f241e 100644
--- a/daemon/xattr.c
+++ b/daemon/xattr.c
@@ -19,6 +19,8 @@
#include <config.h>
#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
#include <limits.h>
#include <unistd.h>
@@ -115,6 +117,29 @@ split_attr_names (char *buf, size_t len)
return take_stringsbuf (&ret);
}
+/* We hide one extended attribute automatically. This is used by NTFS
+ * to store the compressed contents of a file when using "CompactOS"
+ * (per-file compression). I justify this by:
+ *
+ * (1) The attribute is only used internally by NTFS. The actual file
+ * contents are still available.
+ *
+ * (2) It's probably not valid to copy this attribute when copying the
+ * other attributes of a file. ntfs-3g-system-compression doesn't
+ * support writing compressed files.
+ *
+ * (3) This file isn't readable by the Linux kernel. Reading it will
+ * always return -E2BIG (RHBZ#1811539). So we can't read it even if
+ * we wanted to.
+ *
+ * (4) The Linux kernel itself hides other attributes.
+ */
+static bool
+not_hidden_xattr (const char *attrname)
+{
+ return STRNEQ (attrname, "user.WofCompressedData");
+}
+
static int
compare_xattrs (const void *vxa1, const void *vxa2)
{
@@ -132,6 +157,7 @@ getxattrs (const char *path,
{
ssize_t len, vlen;
CLEANUP_FREE char *buf = NULL;
+ CLEANUP_FREE /* not string list */ char **names_unfiltered = NULL;
CLEANUP_FREE /* not string list */ char **names = NULL;
size_t i;
guestfs_int_xattr_list *r = NULL;
@@ -141,7 +167,10 @@ getxattrs (const char *path,
/* _listxattrs issues reply_with_perror already. */
goto error;
- names = split_attr_names (buf, len);
+ names_unfiltered = split_attr_names (buf, len);
+ if (names_unfiltered == NULL)
+ goto error;
+ names = filter_list (not_hidden_xattr, names_unfiltered);
if (names == NULL)
goto error;
@@ -319,6 +348,7 @@ do_internal_lxattrlist (const char *path, char *const *names)
void *newptr;
CLEANUP_FREE char *pathname = NULL;
CLEANUP_FREE char *buf = NULL;
+ CLEANUP_FREE /* not string list */ char **attrnames_unfiltered = NULL;
CLEANUP_FREE /* not string list */ char **attrnames = NULL;
/* Be careful in this loop about which errors cause the whole call
@@ -377,7 +407,10 @@ do_internal_lxattrlist (const char *path, char *const *names)
if (len == -1)
continue; /* not fatal */
- attrnames = split_attr_names (buf, len);
+ attrnames_unfiltered = split_attr_names (buf, len);
+ if (attrnames_unfiltered == NULL)
+ goto error;
+ attrnames = filter_list (not_hidden_xattr, attrnames_unfiltered);
if (attrnames == NULL)
goto error;
nr_attrs = guestfs_int_count_strings (attrnames);
@@ -535,6 +568,7 @@ copy_xattrs (const char *src, const char *dest)
{
ssize_t len, vlen, ret, attrval_len = 0;
CLEANUP_FREE char *buf = NULL, *attrval = NULL;
+ CLEANUP_FREE /* not string list */ char **names_unfiltered = NULL;
CLEANUP_FREE /* not string list */ char **names = NULL;
size_t i;
@@ -543,7 +577,10 @@ copy_xattrs (const char *src, const char *dest)
/* _listxattrs issues reply_with_perror already. */
goto error;
- names = split_attr_names (buf, len);
+ names_unfiltered = split_attr_names (buf, len);
+ if (names_unfiltered == NULL)
+ goto error;
+ names = filter_list (not_hidden_xattr, names_unfiltered);
if (names == NULL)
goto error;
--
2.25.0