Commit 3eb9a3bb authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Stefan Bader

ovl: filter trusted xattr for non-admin

BugLink: http://bugs.launchpad.net/bugs/1765010

[ Upstream commit a082c6f6 ]

Filesystems filter out extended attributes in the "trusted." domain for
unprivlieged callers.

Overlay calls underlying filesystem's method with elevated privs, so need
to do the filtering in overlayfs too.
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJuerg Haefliger <juergh@canonical.com>
Signed-off-by: default avatarStefan Bader <stefan.bader@canonical.com>
parent 6af0f44f
......@@ -272,6 +272,16 @@ ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
return vfs_getxattr(realpath.dentry, name, value, size);
}
static bool ovl_can_list(const char *s)
{
/* List all non-trusted xatts */
if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0)
return true;
/* Never list trusted.overlay, list other trusted for superuser only */
return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN);
}
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
{
struct path realpath;
......@@ -296,7 +306,7 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
return -EIO;
len -= slen;
if (ovl_is_private_xattr(s)) {
if (!ovl_can_list(s)) {
res -= slen;
memmove(s, s + slen, len);
} else {
......
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