[PATCH] Smack: Fix memory leak in smack_inode_getsecctx

[Casey Schaufler]

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 <ca...@schaufler-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;
 }