[Devel] [PATCH RHEL7 COMMIT] ve/fs/devmnt: allow more than one mount option inside a CT

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-514.16.1.vz7.32.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.16.1.vz7.32.11
------>
commit 1414d860283af9004ac5b9f80a802fa75f14ffe3
Author: Konstantin Khorenko <khorenko at virtuozzo.com>
Date:   Tue Jun 27 13:42:45 2017 +0400

    ve/fs/devmnt: allow more than one mount option inside a CT
    
    strsep() changes provided string: puts '\0' instead of separators,
    thus after successful call to ve_devmnt_check() we insert
    only first provided mount options, ignoring others.
    
    Fixes: bc4143b ("ve/fs/devmnt: process mount options")
    
    Found during implementation of
    https://jira.sw.ru/browse/PSBM-40075
    
    Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
    Reviewed-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 fs/namespace.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 7aed8f5..f2d1f84 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1899,6 +1899,7 @@ static char *strstr_separated(char *haystack, char *needle, char sep)
 static int ve_devmnt_check(char *options, char *allowed)
 {
 	char *p;
+	char *tmp_options;
 
 	if (!options || !*options)
 		return 0;
@@ -1906,14 +1907,22 @@ static int ve_devmnt_check(char *options, char *allowed)
 	if (!allowed)
 		return -EPERM;
 
-	while ((p = strsep(&options, ",")) != NULL) {
+	/* strsep() changes provided string: puts '\0' instead of separators */
+	tmp_options = kstrdup(options, GFP_KERNEL);
+	if (!tmp_options)
+		return -ENOMEM;
+
+	while ((p = strsep(&tmp_options, ",")) != NULL) {
 		if (!*p)
 			continue;
 
-		if (!strstr_separated(allowed, p, ','))
+		if (!strstr_separated(allowed, p, ',')) {
+			kfree(tmp_options);
 			return -EPERM;
+		}
 	}
 
+	kfree(tmp_options);
 	return 0;
 }