From: Petko Manolov <petkan@mip-labs.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
James Morris <jmorris@namei.org>,
linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
Mimi Zohar <zohar@linux.vnet.ibm.com>
Subject: Re: linux-next: manual merge of the security tree with the vfs tree
Date: Fri, 1 Jan 2016 19:29:37 +0200 [thread overview]
Message-ID: <20160101172937.GD13634@localhost> (raw)
In-Reply-To: <20160101043416.GE9938@ZenIV.linux.org.uk>
On 16-01-01 04:34:16, Al Viro wrote:
> On Thu, Dec 31, 2015 at 12:45:35PM +0200, Petko Manolov wrote:
>
> > I introduced the write mutex when ima_write_policy() stopped being serialized by
> > other means. Come to think about it the semaphore could be taken right before
> > copy_from_user() so it is my fault, not Stephen's.
>
> s/before/after/, surely?
Right. This is a quick patch which i hope solves most issues...
Petko
>From 6c9058009c59fda5b8e98a3fc09497ce3efdb3e9 Mon Sep 17 00:00:00 2001
From: Petko Manolov <petkan@mip-labs.com>
Date: Fri, 1 Jan 2016 19:10:43 +0200
Subject: [PATCH] ima_write_policy() optimizations;
There is no need to hold the write semaphore for so long. We only need it
around ima_parse_add_rule();
The return path now takes into account failed kmalloc() call.
Signed-off-by: Petko Manolov <petkan@mip-labs.com>
---
security/integrity/ima/ima_fs.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 3caed6d..d2c0d55 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -261,13 +261,7 @@ static const struct file_operations ima_ascii_measurements_ops = {
static ssize_t ima_write_policy(struct file *file, const char __user *buf,
size_t datalen, loff_t *ppos)
{
- char *data = NULL;
ssize_t result;
- int res;
-
- res = mutex_lock_interruptible(&ima_write_mutex);
- if (res)
- return res;
if (datalen >= PAGE_SIZE)
datalen = PAGE_SIZE - 1;
@@ -286,15 +280,21 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
result = -EFAULT;
if (copy_from_user(data, buf, datalen))
- goto out;
+ goto out_free;
+
+ result = mutex_lock_interruptible(&ima_write_mutex);
+ if (result)
+ goto out_free;
result = ima_parse_add_rule(data);
-out:
+
+ mutex_unlock(&ima_write_mutex);
+
if (result < 0)
valid_policy = 0;
+out_free:
kfree(data);
- mutex_unlock(&ima_write_mutex);
-
+out:
return result;
}
--
2.6.4
next prev parent reply other threads:[~2016-01-01 17:29 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-31 4:24 linux-next: manual merge of the security tree with the vfs tree Stephen Rothwell
2015-12-31 4:30 ` Al Viro
2015-12-31 10:45 ` Petko Manolov
2016-01-01 4:34 ` Al Viro
2016-01-01 17:29 ` Petko Manolov [this message]
2016-01-01 17:41 ` [PATCH] ima_write_policy() optimizations; kbuild test robot
2016-01-04 1:37 ` linux-next: manual merge of the security tree with the vfs tree Mimi Zohar
2016-01-04 1:55 ` Stephen Rothwell
-- strict thread matches above, loose matches on Subject: below --
2019-08-12 4:44 Stephen Rothwell
2015-05-13 4:39 Stephen Rothwell
2015-05-13 4:26 Stephen Rothwell
2014-12-10 2:47 Stephen Rothwell
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