diff options
author | Ronnie Sahlberg <lsahlber@redhat.com> | 2018-12-13 08:06:16 +1000 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-02-20 10:13:13 +0100 |
commit | 7d1cfc10d42bbffa224ee7734f129834ad94abc8 (patch) | |
tree | 45ff88e9d55470334e7d47824bf41a4fc993ac20 /fs | |
parent | b49344a2dc4bc1acb58b27fc2a3286661ad4fa88 (diff) |
cifs: check ntwrk_buf_start for NULL before dereferencing it
[ Upstream commit 59a63e479ce36a3f24444c3a36efe82b78e4a8e0 ]
RHBZ: 1021460
There is an issue where when multiple threads open/close the same directory
ntwrk_buf_start might end up being NULL, causing the call to smbCalcSize
later to oops with a NULL deref.
The real bug is why this happens and why this can become NULL for an
open cfile, which should not be allowed.
This patch tries to avoid a oops until the time when we fix the underlying
issue.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/cifs/readdir.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c index 57b039ebfb1f..43fa471c88d7 100644 --- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -652,7 +652,14 @@ find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos, /* scan and find it */ int i; char *cur_ent; - char *end_of_smb = cfile->srch_inf.ntwrk_buf_start + + char *end_of_smb; + + if (cfile->srch_inf.ntwrk_buf_start == NULL) { + cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n"); + return -EIO; + } + + end_of_smb = cfile->srch_inf.ntwrk_buf_start + server->ops->calc_smb_size( cfile->srch_inf.ntwrk_buf_start); |