[lxc-devel] [lxc/lxc] 94bef7: conf: fix read-only bind mounts

[Christian Brauner]

  Branch: refs/heads/master
  Home:   https://github.com/lxc/lxc
  Commit: 94bef7e4b4ee4b8b05bc4ba52b536fdc8d099c2c
      https://github.com/lxc/lxc/commit/94bef7e4b4ee4b8b05bc4ba52b536fdc8d099c2c
  Author: Tycho Andersen <tycho at tycho.ws>
  Date:   2020-03-24 (Tue, 24 Mar 2020)

  Changed paths:
    M src/lxc/conf.c

  Log Message:
  -----------
  conf: fix read-only bind mounts

Here we would always set MS_RDONLY in required_flags if it was set in
mountflags, so the expression:

!(required_flags & ~mountflags)

would always be true, and we would always skip the remount.

Instead, let's treat readonly as special: always do the remount if
MS_RDONLY is present. Unfortunately it doesn't seem to show up in
sb.f_flag, so we can't use the same path as everything else.

This only inadvertently worked before because of a bug fixed in
f75917858023 ("conf: don't accidently double-mount").

Signed-off-by: Tycho Andersen <tycho at tycho.ws>


  Commit: b492fc2a40013b181cdce686658f08b9d7d6a0d9
      https://github.com/lxc/lxc/commit/b492fc2a40013b181cdce686658f08b9d7d6a0d9
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2020-03-24 (Tue, 24 Mar 2020)

  Changed paths:
    M src/lxc/conf.c

  Log Message:
  -----------
  Merge pull request #3323 from tych0/fix-readonly-bind-mounts

conf: fix read-only bind mounts


Compare: https://github.com/lxc/lxc/compare/e4e80aa9e9d0...b492fc2a4001