Found while inspecting the code that handles the setgroups procfs file.
Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@xxxxxxxxx>
---
Tested locally setting up a new userns, and setting setgroups as deny and allow,
worked as before.
kernel/user_namespace.c | 20 +++++++-------------
1 file changed, 7 insertions(+), 13 deletions(-)
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 246d4d4ce5c7..64a01254ac6b 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -1142,22 +1142,18 @@ ssize_t proc_setgroups_write(struct file *file, const char __user *buf,
struct user_namespace *ns = seq->private;
char kbuf[8], *pos;
bool setgroups_allowed;
- ssize_t ret;
/* Only allow a very narrow range of strings to be written */
- ret = -EINVAL;
if ((*ppos != 0) || (count >= sizeof(kbuf)))
- goto out;
+ return -EINVAL;
/* What was written? */
- ret = -EFAULT;
if (copy_from_user(kbuf, buf, count))
- goto out;
+ return -EFAULT;
kbuf[count] = '\0';
pos = kbuf;
/* What is being requested? */
- ret = -EINVAL;
if (strncmp(pos, "allow", 5) == 0) {
pos += 5;
setgroups_allowed = true;
@@ -1167,14 +1163,13 @@ ssize_t proc_setgroups_write(struct file *file, const char __user *buf,
setgroups_allowed = false;
}
else
- goto out;
+ return -EINVAL;
/* Verify there is not trailing junk on the line */
pos = skip_spaces(pos);
if (*pos != '\0')
- goto out;
+ return -EINVAL;
- ret = -EPERM;
mutex_lock(&userns_state_mutex);
if (setgroups_allowed) {
/* Enabling setgroups after setgroups has been disabled
@@ -1194,12 +1189,11 @@ ssize_t proc_setgroups_write(struct file *file, const char __user *buf,
/* Report a successful write */
*ppos = count;
- ret = count;
-out:
- return ret;
+ return count;
+
out_unlock:
mutex_unlock(&userns_state_mutex);
- goto out;
+ return -EPERM;
}
bool userns_may_setgroups(const struct user_namespace *ns)
--
2.14.3
--
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