Re: [RFC][PATCH] setfiles: only call realpath if the path is relative

[Daniel J Walsh <dwalsh@redhat.com>]

On 07/30/2009 11:17 AM, Stephen Smalley wrote:
> Since we can now safely use restorecon -R / on kernels >= 2.6.30 without
> concern about restorecon descending into filesystems that do not support
> labeling, I wanted to compare it against running setfiles on the list of
> filesystems that support labeling.  I noticed a significant difference
> in performance that I traced to the use of realpath() when setfiles is
> called as restorecon.
> 
> When called as restorecon, setfiles calls realpath() so that sequences
> like:
> 	cd /etc
> 	restorecon shadow gshadow
> will work as expected.
> 
> This patch changes the logic to only apply realpath() if the pathname is
> relative, which covers the above case.  However, if a user runs
> restorecon /a/b/c and any of the components is a symlink, restorecon
> won't apply realpath after this patch and thus may not match the correct
> file contexts entry.  Thoughts?
> 
> diff --git a/policycoreutils/setfiles/setfiles.c b/policycoreutils/setfiles/setfiles.c
> index 5e5d957..996d230 100644
> --- a/policycoreutils/setfiles/setfiles.c
> +++ b/policycoreutils/setfiles/setfiles.c
> @@ -311,7 +311,7 @@ int match(const char *name, struct stat *sb, char **con)
>  {
>  	char path[PATH_MAX + 1];
>  
> -	if (expand_realpath) {
> +	if (expand_realpath && name[0] != '/') {
>  		if (S_ISLNK(sb->st_mode)) {
>  			if (verbose > 1)
>  				fprintf(stderr,
> 
> 
The place where this is a problem is

restorecon -Rv /etc/init.d
versus
restorecon -Rv /etc/rc.d/init.d

What happens to the labeling?


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