Messages in this thread | | | Date | Tue, 14 Apr 2009 21:25:44 -0700 | From | Casey Schaufler <> | Subject | Re: [PATCH] Smack: check for SMACK xattr max size in smack_inode_setxattr |
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Etienne Basset wrote: > the following patch move the check for SMACK xattr size >= SMK_LABELLEN > from smack_inode_post_setxattr (which cannot return an error to the user) > to smack_inode_setxattr (which can return an error). > > without patch a SMACK setxattr with size >= SMK_LABELLEN returns success although it doesn't >
How about an early call to smk_import() to determine if the label if legitimate, rather than checking the length? That could save grief for other "invalid label" issues.
> Signed-off-by: Etienne Basset <etienne.basset@numericable.fr> > --- > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index 9215149..da6954d 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -610,7 +610,8 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name, > if (!capable(CAP_MAC_ADMIN)) > rc = -EPERM; > /* a label cannot be void and cannot begin with '-' */ > - if (size == 0 || (size > 0 && ((char *)value)[0] == '-')) > + if (size == 0 || size >= SMK_LABELLEN || > + (size > 0 && ((char *)value)[0] == '-')) > rc = -EINVAL; > } else > rc = cap_inode_setxattr(dentry, name, value, size, flags); > @@ -644,9 +645,6 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name, > if (strcmp(name, XATTR_NAME_SMACK)) > return; > > - if (size >= SMK_LABELLEN) > - return; > - > isp = dentry->d_inode->i_security; > > /* > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > >
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