Re: [PATCH] Smack: Fix memory leak in smack_inode_getsecctx
From: Casey Schaufler
Date: Mon Jun 04 2018 - 17:01:42 EST
On 6/1/2018 10:45 AM, Casey Schaufler wrote:
> 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@xxxxxxxxxxxxxxxx>
Tejun, does this pass your tests?
> ---
> 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;
> }
>
>
> --
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