Messages in this thread | | | Date | Tue, 01 Jun 2010 17:26:06 -0700 | From | Casey Schaufler <> | Subject | Re: [patch] smack: opt_dentry is never null in in smack_d_instantiate() |
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Dan Carpenter wrote: > This patch removes some unneeded code for if opt_dentry is null because > that can never happen. > > The function dereferences "opt_dentry" earlier when it checks > "if (opt_dentry->d_parent == opt_dentry) {". That code was added in > 2008. > > This function called from security_d_instantiate(). I checked all the > places which call security_d_instantiate() and dentry is always non-null. > I also checked the selinux version of this hook and there is a comment > which says that dentry should be non-null if called from > d_instantiate(). > > Signed-off-by: Dan Carpenter <error27@gmail.com> >
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
I have tested the change and not had any issues. I recall struggling with this particular bit of code, but that was long enough ago that the circumstances evade my memory. Thank you.
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index 0f2fc48..07abc9c 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -2191,7 +2191,7 @@ static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid) > > /** > * smack_d_instantiate - Make sure the blob is correct on an inode > - * @opt_dentry: unused > + * @opt_dentry: dentry where inode will be attached > * @inode: the object > * > * Set the inode's security blob if it hasn't been done already. > @@ -2310,20 +2310,10 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) > /* > * Get the dentry for xattr. > */ > - if (opt_dentry == NULL) { > - dp = d_find_alias(inode); > - if (dp == NULL) > - break; > - } else { > - dp = dget(opt_dentry); > - if (dp == NULL) > - break; > - } > - > + dp = dget(opt_dentry); > fetched = smk_fetch(inode, dp); > if (fetched != NULL) > final = fetched; > - > dput(dp); > break; > } > > >
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