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authorAndrew Vagin <avagin@openvz.org>2012-09-17 14:09:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-09-17 15:00:38 -0700
commit579035dc5ddd6d48fd8529e7358b03d911ab9d8a (patch)
treebd54e0a33715547454b241124258c0c3c0d2be5e /kernel/pid_namespace.c
parent35c448a8a3471b95ebc0ebcf91eb1183401b4274 (diff)
downloadvexpress-lsk-579035dc5ddd6d48fd8529e7358b03d911ab9d8a.tar.gz
pid-namespace: limit value of ns_last_pid to (0, max_pid)
The kernel doesn't check the pid for negative values, so if you try to write -2 to /proc/sys/kernel/ns_last_pid, you will get a kernel panic. The crash happens because the next pid is -1, and alloc_pidmap() will try to access to a nonexistent pidmap. map = &pid_ns->pidmap[pid/BITS_PER_PAGE]; Signed-off-by: Andrew Vagin <avagin@openvz.org> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/pid_namespace.c')
-rw-r--r--kernel/pid_namespace.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index b3c7fd55425..6144bab8fd8 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -232,15 +232,19 @@ static int pid_ns_ctl_handler(struct ctl_table *table, int write,
*/
tmp.data = &current->nsproxy->pid_ns->last_pid;
- return proc_dointvec(&tmp, write, buffer, lenp, ppos);
+ return proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
}
+extern int pid_max;
+static int zero = 0;
static struct ctl_table pid_ns_ctl_table[] = {
{
.procname = "ns_last_pid",
.maxlen = sizeof(int),
.mode = 0666, /* permissions are checked in the handler */
.proc_handler = pid_ns_ctl_handler,
+ .extra1 = &zero,
+ .extra2 = &pid_max,
},
{ }
};