[pve-devel] [PATCH] implement chown and chmod for user root group www-data and perm 0640

[Thomas Lamprecht]

small comment inline,

On 03/09/2017 08:17 PM, Stefan Priebe wrote:
> This allows us to use management software for files inside of /etc/pve.
> f.e. saltstack which rely on being able to set uid,gid and chmod
>
> Signed-off-by: Stefan Priebe <s.priebe at profihost.ag>
> ---
>   data/src/pmxcfs.c | 33 ++++++++++++++++++++++++++++++++-
>   1 file changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/data/src/pmxcfs.c b/data/src/pmxcfs.c
> index 1b6cbcc..1204331 100644
> --- a/data/src/pmxcfs.c
> +++ b/data/src/pmxcfs.c
> @@ -186,6 +186,35 @@ ret:
>   	return ret;
>   }
>   
> +static int cfs_fuse_chmod(const char *path, mode_t mode)
> +{
> +	int ret = -EACCES;
> +
> +	cfs_debug("enter cfs_fuse_chmod %s", path);
> +
> +	// asserts 0640, but allows setting UID and GID - some programs need that
> +	if ((mode & ACCESSPERMS) == (S_IRUSR | S_IWUSR | S_IRGRP))
> +		ret = 0;
> +
> +	cfs_debug("leave cfs_fuse_chmod %s (%d) mode: %o", path, ret, (int)mode);
> +
> +	return ret;
> +}
> +
> +static int cfs_fuse_chown(const char *path, uid_t user, gid_t group)
> +{
> +	int ret = -EACCES;
> +
> +	cfs_debug("enter cfs_fuse_chown %s", path);

Can we add the uid and gid to the debug message, I already needed them 
to review the patch:

cfs_debug("enter cfs_fuse_chown %s (uid: %d; gid: %d)", path, user, group);

> +
> +	if (user == 0 && group == cfs.gid)

If we do not change either group or user chmod uses `-1` for that parameter.
So something like this:

         // we get -1 if no change should be made
         if ((user == 0 || user == -1) && (group == cfs.gid || group == -1))

should be done here, this allows also:

chmod root /etc/pve/...
chmod :www-data /etc/pve/...

else only
chmod root:www-data /etc/pve/...

was allowed (all three are valid for us).

The rest looks good for me as is!

With the above changes made you may pickup my reviewed tag - if wanted:
Reviewed-by Thomas Lamprecht <t.lamprecht at proxmox.com>

> +		ret = 0;
> +
> +	cfs_debug("leave cfs_fuse_chown %s (%d)", path, ret);
> +
> +	return ret;
> +}
> +
>   static int cfs_fuse_mkdir(const char *path, mode_t mode)
>   {
>   	cfs_debug("enter cfs_fuse_mkdir %s", path);
> @@ -488,7 +517,9 @@ static struct fuse_operations fuse_ops = {
>   	.readlink = cfs_fuse_readlink,
>   	.utimens = cfs_fuse_utimens,
>   	.statfs = cfs_fuse_statfs,
> -	.init = cfs_fuse_init
> +	.init = cfs_fuse_init,
> +	.chown = cfs_fuse_chown,
> +	.chmod = cfs_fuse_chmod
>   };
>   
>   static char *