[PATCH -next 0/5] fs: fix possible null-ptr-deref when parsing param

[Hawkins Jiawei <yin31149@gmail.com>]

According to commit "vfs: parse: deal with zero length string value",
kernel will set the param->string to null pointer in vfs_parse_fs_string()
if fs string has zero length.

Yet the problem is that, when fs parses its mount parameters, it will
dereferences the param->string, without checking whether it is a
null pointer, which may trigger a null-ptr-deref bug.

So this patchset reviews all functions for fs to parse parameters,
by using `git grep -n "\.parse_param" fs/*`, and adds sanity check
on param->string if its function will dereference param->string
without check.

Hawkins Jiawei (5):
  smb3: fix possible null-ptr-deref when parsing param
  nfs: fix possible null-ptr-deref when parsing param
  ceph: fix possible null-ptr-deref when parsing param
  gfs2: fix possible null-ptr-deref when parsing param
  proc: fix possible null-ptr-deref when parsing param

 fs/ceph/super.c      |  3 +++
 fs/cifs/fs_context.c | 58 +++++++++++++++++++++++++++++++++++++++++++-
 fs/gfs2/ops_fstype.c | 10 ++++++++
 fs/nfs/fs_context.c  |  6 +++++
 fs/proc/root.c       |  3 +++
 5 files changed, 79 insertions(+), 1 deletion(-)

-- 
2.25.1