From: David Disseldorp ddiss@suse.de
[ Upstream commit 2b2abcac8c251d1c77a4cc9d9f248daefae0fb4e ]
ceph_listxattr() incorrectly returns a length based on the static ceph_vxattrs_name_size() value, which only takes into account whether vxattrs are hidden, ignoring vxattr.exists_cb().
When filling the xattr buffer ceph_listxattr() checks VXATTR_FLAG_HIDDEN and vxattr.exists_cb(). If both are false, we return an incorrect (oversize) length.
Fix this behaviour by always calculating the vxattrs length at runtime, taking both vxattr.hidden and vxattr.exists_cb() into account.
This bug is only exposed with the new "ceph.snap.btime" vxattr, as all other vxattrs with a non-null exists_cb also carry VXATTR_FLAG_HIDDEN.
Signed-off-by: David Disseldorp ddiss@suse.de Reviewed-by: "Yan, Zheng" zyan@redhat.com Signed-off-by: Ilya Dryomov idryomov@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ceph/xattr.c | 54 +++++++++++++++++++++++++++---------------------- 1 file changed, 30 insertions(+), 24 deletions(-)
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c index 5cc8b94f8206..996ee87b1eaf 100644 --- a/fs/ceph/xattr.c +++ b/fs/ceph/xattr.c @@ -879,10 +879,9 @@ ssize_t ceph_listxattr(struct dentry *dentry, char *names, size_t size) struct inode *inode = d_inode(dentry); struct ceph_inode_info *ci = ceph_inode(inode); struct ceph_vxattr *vxattrs = ceph_inode_vxattrs(inode); - u32 vir_namelen = 0; + bool len_only = (size == 0); u32 namelen; int err; - u32 len; int i;
spin_lock(&ci->i_ceph_lock); @@ -901,38 +900,45 @@ ssize_t ceph_listxattr(struct dentry *dentry, char *names, size_t size) err = __build_xattrs(inode); if (err < 0) goto out; - /* - * Start with virtual dir xattr names (if any) (including - * terminating '\0' characters for each). - */ - vir_namelen = ceph_vxattrs_name_size(vxattrs);
- /* adding 1 byte per each variable due to the null termination */ + /* add 1 byte for each xattr due to the null termination */ namelen = ci->i_xattrs.names_size + ci->i_xattrs.count; - err = -ERANGE; - if (size && vir_namelen + namelen > size) - goto out; - - err = namelen + vir_namelen; - if (size == 0) - goto out; + if (!len_only) { + if (namelen > size) { + err = -ERANGE; + goto out; + } + names = __copy_xattr_names(ci, names); + size -= namelen; + }
- names = __copy_xattr_names(ci, names);
/* virtual xattr names, too */ - err = namelen; if (vxattrs) { for (i = 0; vxattrs[i].name; i++) { - if (!(vxattrs[i].flags & VXATTR_FLAG_HIDDEN) && - !(vxattrs[i].exists_cb && - !vxattrs[i].exists_cb(ci))) { - len = sprintf(names, "%s", vxattrs[i].name); - names += len + 1; - err += len + 1; + size_t this_len; + + if (vxattrs[i].flags & VXATTR_FLAG_HIDDEN) + continue; + if (vxattrs[i].exists_cb && !vxattrs[i].exists_cb(ci)) + continue; + + this_len = strlen(vxattrs[i].name) + 1; + namelen += this_len; + if (len_only) + continue; + + if (this_len > size) { + err = -ERANGE; + goto out; } + + memcpy(names, vxattrs[i].name, this_len); + names += this_len; + size -= this_len; } } - + err = namelen; out: spin_unlock(&ci->i_ceph_lock); return err;