5.4-stable review patch. If anyone has any objections, please let me know.
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From: Paulo Alcantara pc@manguebit.com
[ Upstream commit 92414333eb375ed64f4ae92d34d579e826936480 ]
If server returned no data for FSCTL_DFS_GET_REFERRALS, @dfs_rsp will remain NULL and then parse_dfs_referrals() will dereference it.
Fix this by returning -EIO when no output data is returned.
Besides, we can't fix it in SMB2_ioctl() as some FSCTLs are allowed to return no data as per MS-SMB2 2.2.32.
Fixes: 9d49640a21bf ("CIFS: implement get_dfs_refer for SMB2+") Cc: stable@vger.kernel.org Reported-by: Robert Morris rtm@csail.mit.edu Signed-off-by: Paulo Alcantara (SUSE) pc@manguebit.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cifs/smb2ops.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index ad9b207432e10..5fea15a5f3419 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -2498,6 +2498,8 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses, (char **)&dfs_rsp, &dfs_rsp_size); } while (rc == -EAGAIN);
+ if (!rc && !dfs_rsp) + rc = -EIO; if (rc) { if ((rc != -ENOENT) && (rc != -EOPNOTSUPP)) cifs_tcon_dbg(VFS, "ioctl error in %s rc=%d\n", __func__, rc);