Linux-Security-Module Archive on lore.kernel.org
 help / color / Atom feed
From: David Howells <dhowells@redhat.com>
To: Paul Moore <paul@paul-moore.com>
Cc: dhowells@redhat.com, keyrings@vger.kernel.org,
	selinux@vger.kernel.org, linux-security-module@vger.kernel.org
Subject: [PATCH] selinux: Fix use of KEY_NEED_* instead of KEY__* perms
Date: Mon, 27 Apr 2020 15:12:14 +0100
Message-ID: <355576.1587996734@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAHC9VhQbhG8-ZABtkZr1FXo9cuH4_nsbB=HP_fGvW+FNQ7iAXg@mail.gmail.com>

Paul Moore <paul@paul-moore.com> wrote:

> Okay, can you send the next version of the patch to the SELinux list for
> review?

Here you go.  Note that I did this a few days ago and I actually used EACCES
rather than EPERM.  Which one is one preferred for this?

David
---
selinux: Fix use of KEY_NEED_* instead of KEY__* perms

selinux_key_getsecurity() is passing the KEY_NEED_* permissions to
security_sid_to_context() instead of the KEY__* values.  It happens to work
because the values are all coincident.

Fixes: d720024e94de ("[PATCH] selinux: add hooks for key subsystem")
Reported-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
 security/selinux/hooks.c |   22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 0b4e32161b77..6087955b49d8 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6539,20 +6539,38 @@ static void selinux_key_free(struct key *k)
 	kfree(ksec);
 }
 
+static unsigned int selinux_keyperm_to_av(unsigned int need_perm)
+{
+	switch (need_perm) {
+	case KEY_NEED_VIEW:	return KEY__VIEW;
+	case KEY_NEED_READ:	return KEY__READ;
+	case KEY_NEED_WRITE:	return KEY__WRITE;
+	case KEY_NEED_SEARCH:	return KEY__SEARCH;
+	case KEY_NEED_LINK:	return KEY__LINK;
+	case KEY_NEED_SETATTR:	return KEY__SETATTR;
+	default:
+		return 0;
+	}
+}
+
 static int selinux_key_permission(key_ref_t key_ref,
 				  const struct cred *cred,
-				  unsigned perm)
+				  unsigned need_perm)
 {
 	struct key *key;
 	struct key_security_struct *ksec;
+	unsigned int perm;
 	u32 sid;
 
 	/* if no specific permissions are requested, we skip the
 	   permission check. No serious, additional covert channels
 	   appear to be created. */
-	if (perm == 0)
+	if (need_perm == 0)
 		return 0;
 
+	perm = selinux_keyperm_to_av(need_perm);
+	if (perm == 0)
+		return -EACCES;
 	sid = cred_sid(cred);
 
 	key = key_ref_to_ptr(key_ref);


  parent reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-17 15:48 Problem with 9ba09998baa9 ("selinux: Implement the watch_key security hook") in linux-next Paul Moore
2020-04-17 16:32 ` Richard Haines
2020-04-17 16:59   ` Paul Moore
2020-04-21 12:29 ` David Howells
2020-04-22 19:20   ` Paul Moore
2020-04-22 21:09     ` Paul Moore
2020-04-24 23:43   ` David Howells
2020-04-26 20:53     ` Paul Moore
2020-04-27 14:12     ` David Howells [this message]
2020-04-27 14:36       ` [PATCH] selinux: Fix use of KEY_NEED_* instead of KEY__* perms Stephen Smalley
2020-04-27 15:24         ` Paul Moore
2020-04-27 17:02       ` Stephen Smalley
2020-04-27 22:17         ` Paul Moore
2020-04-28 12:54 ` [PATCH] selinux: Fix use of KEY_NEED_* instead of KEY__* perms [v2] David Howells
2020-04-28 14:32   ` Stephen Smalley
2020-04-28 15:57   ` David Howells
2020-04-28 16:19     ` Stephen Smalley
2020-05-01 16:37       ` Paul Moore
2020-05-12 22:33       ` [PATCH] keys: Make the KEY_NEED_* perms an enum rather than a mask David Howells
2020-05-13  1:04         ` Paul Moore
2020-05-13 12:58         ` Stephen Smalley
2020-05-13 15:25         ` Casey Schaufler
2020-05-13 23:13         ` David Howells
2020-05-14 12:08           ` Stephen Smalley
2020-05-14 14:45             ` Stephen Smalley
2020-05-13 23:16         ` David Howells
2020-05-13 23:25         ` David Howells
2020-05-14 11:00         ` Jarkko Sakkinen
2020-05-14 16:58         ` [PATCH] keys: Move permissions checking decisions into the checking code David Howells
2020-05-14 17:06           ` Casey Schaufler
2020-05-15 15:06           ` Stephen Smalley
2020-05-15 16:45           ` David Howells
2020-05-15 18:55             ` Stephen Smalley
2020-05-15 19:10               ` Casey Schaufler
2020-05-15 22:27             ` David Howells

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=355576.1587996734@warthog.procyon.org.uk \
    --to=dhowells@redhat.com \
    --cc=keyrings@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=paul@paul-moore.com \
    --cc=selinux@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Security-Module Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-security-module/0 linux-security-module/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-security-module linux-security-module/ https://lore.kernel.org/linux-security-module \
		linux-security-module@vger.kernel.org
	public-inbox-index linux-security-module

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-security-module


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git