Re: [PATCH] LXC: make sure netns been enabled when trying to enable userns

[Martin Kletzander <mkletzan@xxxxxxxxxx>]

On Fri, Mar 20, 2015 at 05:58:22AM -0400, Chen Hanxiao wrote:
> This patch revert commit:
> 7dc5dbc879bd0779924b5132a48b731a0bc04a1e

I haven't found this commit in the log, also this is not how reverts
should be done, please use "git revert <commit_id>", it basically
cherry-picks inverted version of that patch, so resolutions may be
done for conflicts, and it will let you amend the commit messsage.

> Discussed at:
> http://www.redhat.com/archives/libvir-list/2015-March/msg01023.html
>
> Signed-off-by: Chen Hanxiao <chenhanxiao@xxxxxxxxxxxxxx>
> ---
> src/lxc/lxc_container.c | 45 ++++++++++++++++-----------------------------
> 1 file changed, 16 insertions(+), 29 deletions(-)
>
> diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c
> index cc20b6d..69a8f2f 100644
> --- a/src/lxc/lxc_container.c
> +++ b/src/lxc/lxc_container.c
> @@ -934,8 +934,6 @@ static int lxcContainerMountBasicFS(bool userns_enabled,
> {
>     size_t i;
>     int rc = -1;
> -    char* mnt_src = NULL;
> -    int mnt_mflags;
>
>     VIR_DEBUG("Mounting basic filesystems");
>
> @@ -944,22 +942,17 @@ static int lxcContainerMountBasicFS(bool userns_enabled,
>         virLXCBasicMountInfo const *mnt = &lxcBasicMounts[i];
>
>         /* When enable userns but disable netns, kernel will
> -         * forbid us doing a new fresh mount for sysfs.
> -         * So we had to do a bind mount for sysfs instead.
> +         * forbid us doing a new fresh mount for sysfs for security reason.
> +         * So we should not allow this.
>          */
> -        if (userns_enabled && netns_disabled &&
> -            STREQ(mnt->src, "sysfs")) {
> -            if (VIR_STRDUP(mnt_src, "/sys") < 0)
> -                goto cleanup;
> -            mnt_mflags = MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY|MS_BIND;
> -        } else {
> -            if (VIR_STRDUP(mnt_src, mnt->src) < 0)
> -                goto cleanup;
> -            mnt_mflags = mnt->mflags;
> +        if (userns_enabled && netns_disabled) {
> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                           _("Userns could not be enabled without netns"));
> +            goto cleanup;
>         }
>
>         VIR_DEBUG("Processing %s -> %s",
> -                  mnt_src, mnt->dst);
> +                  mnt->src, mnt->dst);
>
>         if (mnt->skipUnmounted) {
>             char *hostdir;
> @@ -976,28 +969,24 @@ static int lxcContainerMountBasicFS(bool userns_enabled,
>             if (ret == 0) {
>                 VIR_DEBUG("Skipping '%s' which isn't mounted in host",
>                           mnt->dst);
> -                VIR_FREE(mnt_src);
>                 continue;
>             }
>         }
>
>         if (mnt->skipUserNS && userns_enabled) {
>             VIR_DEBUG("Skipping due to user ns enablement");
> -            VIR_FREE(mnt_src);
>             continue;
>         }
>
>         /* Skip mounts with missing source without shouting: it may be a
>          * missing folder in /proc due to the absence of a kernel feature */
> -        if (STRPREFIX(mnt_src, "/") && !virFileExists(mnt_src)) {
> -            VIR_DEBUG("Skipping due to missing source: %s", mnt_src);
> -            VIR_FREE(mnt_src);
> +        if (STRPREFIX(mnt->src, "/") && !virFileExists(mnt->src)) {
> +            VIR_DEBUG("Skipping due to missing source: %s", mnt->src);
>             continue;
>         }
>
>         if (mnt->skipNoNetns && netns_disabled) {
>             VIR_DEBUG("Skipping due to absence of network namespace");
> -            VIR_FREE(mnt_src);
>             continue;
>         }
>
> @@ -1015,35 +1004,33 @@ static int lxcContainerMountBasicFS(bool userns_enabled,
>          * we mount the filesystem in read-write mode initially, and then do a
>          * separate read-only bind mount on top of that.
>          */
> -        bindOverReadonly = !!(mnt_mflags & MS_RDONLY);
> +        bindOverReadonly = !!(mnt->mflags & MS_RDONLY);
>
>         VIR_DEBUG("Mount %s on %s type=%s flags=%x",
> -                  mnt_src, mnt->dst, mnt->type, mnt_mflags & ~MS_RDONLY);
> -        if (mount(mnt_src, mnt->dst, mnt->type, mnt_mflags & ~MS_RDONLY, NULL) < 0) {
> +                  mnt->src, mnt->dst, mnt->type, mnt->mflags & ~MS_RDONLY);
> +        if (mount(mnt->src, mnt->dst, mnt->type, mnt->mflags & ~MS_RDONLY, NULL) < 0) {
>             virReportSystemError(errno,
>                                  _("Failed to mount %s on %s type %s flags=%x"),
> -                                 mnt_src, mnt->dst, NULLSTR(mnt->type),
> -                                 mnt_mflags & ~MS_RDONLY);
> +                                 mnt->src, mnt->dst, NULLSTR(mnt->type),
> +                                 mnt->mflags & ~MS_RDONLY);
>             goto cleanup;
>         }
>
>         if (bindOverReadonly &&
> -            mount(mnt_src, mnt->dst, NULL,
> +            mount(mnt->src, mnt->dst, NULL,
>                   MS_BIND|MS_REMOUNT|MS_RDONLY, NULL) < 0) {
>             virReportSystemError(errno,
>                                  _("Failed to re-mount %s on %s flags=%x"),
> -                                 mnt_src, mnt->dst,
> +                                 mnt->src, mnt->dst,
>                                  MS_BIND|MS_REMOUNT|MS_RDONLY);
>             goto cleanup;
>         }
>
> -        VIR_FREE(mnt_src);
>     }
>
>     rc = 0;
>
>  cleanup:
> -    VIR_FREE(mnt_src);
>     VIR_DEBUG("rc=%d", rc);
>     return rc;
> }
> --
> 2.1.0
>
> --
> libvir-list mailing list
> libvir-list@xxxxxxxxxx
> https://www.redhat.com/mailman/listinfo/libvir-list

Attachment: pgpEKR9GgVj0D.pgp
Description: PGP signature

--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list