linux-kernel - [PATCH] Smack: Fix memory leak in smack_inode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <fa278910-5c99-11dc-c9cb-b88a97592e53@schaufler-ca.com>
Date:   Fri, 1 Jun 2018 10:45:12 -0700
From:   Casey Schaufler <casey@...aufler-ca.com>
To:     chandan.vn@...sung.com,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>
Cc:     Tejun Heo <tj@...nel.org>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "bfields@...ldses.org" <bfields@...ldses.org>,
        "jlayton@...nel.org" <jlayton@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
        CPGS <cpgs@...sung.com>,
        Sireesha Talluri <sireesha.t@...sung.com>,
        Chris Wright <chrisw@...s-sol.org>,
        Casey Schaufler <casey@...aufler-ca.com>
Subject: [PATCH] Smack: Fix memory leak in smack_inode_getsecctx

Fix memory leak in smack_inode_getsecctx

The implementation of smack_inode_getsecctx() made
incorrect assumptions about how Smack presents a security
context. Smack does not need to allocate memory to support
security contexts, so "releasing" a Smack context is a no-op.
The code made an unnecessary copy and returned that as a
context, which was never freed. The revised implementation
returns the context correctly.

Signed-off-by: Casey Schaufler <casey@...aufler-ca.com>
---
 security/smack/smack_lsm.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 0b414836bebd..5e3beae334a8 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1545,9 +1545,9 @@ static int smack_inode_listsecurity(struct inode *inode, char *buffer,
  */
 static void smack_inode_getsecid(struct inode *inode, u32 *secid)
 {
-	struct inode_smack *isp = inode->i_security;
+	struct smack_known *skp = smk_of_inode(inode);
 
-	*secid = isp->smk_inode->smk_secid;
+	*secid = skp->smk_secid;
 }
 
 /*
@@ -4538,12 +4538,10 @@ static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
 
 static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
 {
-	int len = 0;
-	len = smack_inode_getsecurity(inode, XATTR_SMACK_SUFFIX, ctx, true);
+	struct smack_known *skp = smk_of_inode(inode);
 
-	if (len < 0)
-		return len;
-	*ctxlen = len;
+	*ctx = skp->smk_known;
+	*ctxlen = strlen(skp->smk_known);
 	return 0;
 }