Thread (11 messages) 11 messages, 3 authors, 2023-01-23

Re: [PATCH v2] security: Restore passing final prot to ima_file_mmap()

From: Paul Moore <paul@paul-moore.com>
Date: 2023-01-23 21:04:05
Also in: linux-integrity, lkml, stable

On Mon, Jan 23, 2023 at 3:30 AM Roberto Sassu
[off-list ref] wrote:
On Fri, 2023-01-20 at 16:04 -0500, Paul Moore wrote:
quoted
On Fri, Jan 13, 2023 at 5:53 AM Roberto Sassu
[off-list ref] wrote:
quoted
On Thu, 2023-01-12 at 12:45 -0500, Mimi Zohar wrote:
quoted
On Thu, 2023-01-12 at 13:36 +0100, Roberto Sassu wrote:
quoted
On Wed, 2023-01-11 at 09:25 -0500, Paul Moore wrote:
quoted
On Wed, Jan 11, 2023 at 4:31 AM Roberto Sassu
[off-list ref] wrote:
quoted
On Fri, 2023-01-06 at 16:14 -0500, Paul Moore wrote:
quoted
On Wed, Dec 21, 2022 at 9:10 AM Roberto Sassu
[off-list ref] wrote:
quoted
From: Roberto Sassu <roberto.sassu@huawei.com>

Commit 98de59bfe4b2f ("take calculation of final prot in
security_mmap_file() into a helper") moved the code to update prot with the
actual protection flags to be granted to the requestor by the kernel to a
helper called mmap_prot(). However, the patch didn't update the argument
passed to ima_file_mmap(), making it receive the requested prot instead of
the final computed prot.

A possible consequence is that files mmapped as executable might not be
measured/appraised if PROT_EXEC is not requested but subsequently added in
the final prot.

Replace prot with mmap_prot(file, prot) as the second argument of
ima_file_mmap() to restore the original behavior.

Cc: stable@vger.kernel.org
Fixes: 98de59bfe4b2 ("take calculation of final prot in security_mmap_file() into a helper")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 security/security.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/security/security.c b/security/security.c
index d1571900a8c7..0d2359d588a1 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1666,7 +1666,7 @@ int security_mmap_file(struct file *file, unsigned long prot,
                                        mmap_prot(file, prot), flags);
        if (ret)
                return ret;
-       return ima_file_mmap(file, prot);
+       return ima_file_mmap(file, mmap_prot(file, prot));
 }
This seems like a reasonable fix, although as the original commit is
~10 years old at this point I am a little concerned about the impact
this might have on IMA.  Mimi, what do you think?
So ... where do we stand on this patch, Mimi, Roberto?  I stand by my
original comment, but I would want to see an ACK from Mimi at the very
least before merging this upstream.  If this isn't ACK-able, do we
have a plan to resolve this soon?
Sorry, I had business trips last week. Will send the patches this week.
No worries, I just wasn't sure of the status and wanted to check in on this.

-- 
paul-moore.com
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