From ac6ad7a8c9f6f1fd43262b2273a45ec1fdd3a981 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Mon, 2 Sep 2019 16:10:59 +0100 Subject: [PATCH] cifs: fix dereference on ses before it is null checked The assignment of pointer server dereferences pointer ses, however, this dereference occurs before ses is null checked and hence we have a potential null pointer dereference. Fix this by only dereferencing ses after it has been null checked. Addresses-Coverity: ("Dereference before null check") Fixes: 2808c6639104 ("cifs: add new debugging macro cifs_server_dbg") Signed-off-by: Colin Ian King Signed-off-by: Steve French --- fs/cifs/smb2pdu.c | 11 ++++++++--- fs/cifs/transport.c | 3 ++- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index dbc6ef50dd45..0e92983de0b7 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -2759,8 +2759,10 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid, else return -EIO; + if (!ses) + return -EIO; server = ses->server; - if (!ses || !(server)) + if (!server) return -EIO; if (smb3_encryption_required(tcon)) @@ -3058,13 +3060,16 @@ query_info(const unsigned int xid, struct cifs_tcon *tcon, int rc = 0; int resp_buftype = CIFS_NO_BUFFER; struct cifs_ses *ses = tcon->ses; - struct TCP_Server_Info *server = ses->server; + struct TCP_Server_Info *server; int flags = 0; bool allocated = false; cifs_dbg(FYI, "Query Info\n"); - if (!ses || !(server)) + if (!ses) + return -EIO; + server = ses->server; + if (!server) return -EIO; if (smb3_encryption_required(tcon)) diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index 0d60bd2f4dca..a90bd4d75b4d 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -1242,12 +1242,13 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses, struct kvec iov = { .iov_base = in_buf, .iov_len = len }; struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 }; struct cifs_credits credits = { .value = 1, .instance = 0 }; - struct TCP_Server_Info *server = ses->server; + struct TCP_Server_Info *server; if (ses == NULL) { cifs_dbg(VFS, "Null smb session\n"); return -EIO; } + server = ses->server; if (server == NULL) { cifs_dbg(VFS, "Null tcp session\n"); return -EIO;