Commit d33030e2 authored by Jeffrey Mitchell's avatar Jeffrey Mitchell Committed by Trond Myklebust

nfs: Fix security label length not being reset

nfs_readdir_page_filler() iterates over entries in a directory, reusing
the same security label buffer, but does not reset the buffer's length.
This causes decode_attr_security_label() to return -ERANGE if an entry's
security label is longer than the previous one's. This error, in
nfs4_decode_dirent(), only gets passed up as -EAGAIN, which causes another
failed attempt to copy into the buffer. The second error is ignored and
the remaining entries do not show up in ls, specifically the getdents64()
syscall.

Reproduce by creating multiple files in NFS and giving one of the later
files a longer security label. ls will not see that file nor any that are
added afterwards, though they will exist on the backend.

In nfs_readdir_page_filler(), reset security label buffer length before
every reuse
Signed-off-by: default avatarJeffrey Mitchell <jeffrey.mitchell@starlab.io>
Fixes: b4487b93 ("nfs: Fix getxattr kernel panic and memory overflow")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 856deb86
......@@ -579,6 +579,9 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
do {
if (entry->label)
entry->label->len = NFS4_MAXLABELLEN;
status = xdr_decode(desc, entry, &stream);
if (status != 0) {
if (status == -EAGAIN)
......
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