Fix UTS corruption during clone(CLONE_NEWUTS)
struct utsname is copied from master one without any exclusion.
Here is sample output from one proggie doing
sethostname("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
sethostname("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb");
and another
clone(,, CLONE_NEWUTS, ...)
uname()
hostname = 'aaaaaaaaaaaaaaaaaaaaaaaaabbbbb'
hostname = 'bbbaaaaaaaaaaaaaaaaaaaaaaaaaaa'
hostname = 'aaaaaaaabbbbbbbbbbbbbbbbbbbbbb'
hostname = 'aaaaaaaaaaaaaaaaaaaaaaaaaabbbb'
hostname = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaabb'
hostname = 'aaabbbbbbbbbbbbbbbbbbbbbbbbbbb'
hostname = 'bbbbbbbbbbbbbbbbaaaaaaaaaaaaaa'
Hostname is sometimes corrupted.
Yes, even _the_ simplest namespace activity had bug in it. :-(
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/utsname.c b/kernel/utsname.c
index 9d8180a..816d7b2 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -28,7 +28,9 @@
if (!ns)
return ERR_PTR(-ENOMEM);
+ down_read(&uts_sem);
memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+ up_read(&uts_sem);
kref_init(&ns->kref);
return ns;
}