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Message-Id: <1380140085-29712-9-git-send-email-tixxdz@opendz.org>
Date: Wed, 25 Sep 2013 21:14:41 +0100
From: Djalal Harouni <tixxdz@...ndz.org>
To: "Eric W. Biederman" <ebiederm@...ssion.com>,
Kees Cook <keescook@...omium.org>,
Al Viro <viro@...iv.linux.org.uk>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Ingo Molnar <mingo@...nel.org>,
"Serge E. Hallyn" <serge.hallyn@...ntu.com>,
Cyrill Gorcunov <gorcunov@...nvz.org>,
LKML <linux-kernel@...r.kernel.org>,
linux-fsdevel@...r.kernel.org,
<kernel-hardening@...ts.openwall.com>
Cc: tixxdz@...il.com,
Djalal Harouni <tixxdz@...ndz.org>
Subject: [PATCH 08/12] procfs: add permission checks on the file's opener of /proc/*/personality
If current's cred have changed between ->open() and ->read(), then call
proc_allow_access() to check if the original file's opener had enough
permissions to access the /proc/*/personality entry during ->read().
Cc: Kees Cook <keescook@...omium.org>
Cc: Eric W. Biederman <ebiederm@...ssion.com>
Signed-off-by: Djalal Harouni <tixxdz@...ndz.org>
---
fs/proc/base.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index d6a17b3..ed8e3f7 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2656,11 +2656,21 @@ static const struct file_operations proc_projid_map_operations = {
static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
+ const struct cred *fcred = seq_f_cred(m);
+ int same_cred = proc_same_open_cred(fcred);
int err = lock_trace(task);
- if (!err) {
- seq_printf(m, "%08x\n", task->personality);
- unlock_trace(task);
+ if (err)
+ return err;
+
+ if (!same_cred &&
+ !proc_allow_access(fcred, task, PTRACE_MODE_ATTACH)) {
+ err = -EPERM;
+ goto out;
}
+
+ seq_printf(m, "%08x\n", task->personality);
+out:
+ unlock_trace(task);
return err;
}
--
1.7.11.7
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