Re: [PATCH v19 16/23] LSM: Use lsmcontext in security_inode_getsecctx

Change the security_inode_getsecctx() interface to fill a lsmcontext structure instead of data and length pointers. This provides the information about which LSM created the context so that security_release_secctx() can use the correct hook.

Acked-by: Stephen Smalley <sds(a)tycho.nsa.gov&gt; Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com&gt; --- fs/nfsd/nfs4xdr.c | 23 +++++++++-------------- include/linux/security.h | 5 +++-- security/security.c | 13 +++++++++++-- 3 files changed, 23 insertions(+), 18 deletions(-) diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 61d6b8a0e8f0..6673221d5606 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -2379,11 +2379,11 @@ nfsd4_encode_layout_types(struct xdr_stream *xdr, u32 layout_types) #ifdef CONFIG_NFSD_V4_SECURITY_LABEL static inline __be32 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp, - void *context, int len) + struct lsmcontext *context) { __be32 *p; - p = xdr_reserve_space(xdr, len + 4 + 4 + 4); + p = xdr_reserve_space(xdr, context->len + 4 + 4 + 4); if (!p) return nfserr_resource; @@ -2393,13 +2393,13 @@ nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp, */ *p++ = cpu_to_be32(0); /* lfs */ *p++ = cpu_to_be32(0); /* pi */ - p = xdr_encode_opaque(p, context, len); + p = xdr_encode_opaque(p, context->context, context->len); return 0; } #else static inline __be32 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp, - void *context, int len) + struct lsmcontext *context) { return 0; } #endif @@ -2496,9 +2496,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp, int err; struct nfs4_acl *acl = NULL; #ifdef CONFIG_NFSD_V4_SECURITY_LABEL - struct lsmcontext scaff; /* scaffolding */ - void *context = NULL; - int contextlen; + struct lsmcontext context = { }; #endif bool contextsupport = false; struct nfsd4_compoundres *resp = rqstp->rq_resp; @@ -2556,7 +2554,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp, bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) { if (exp->ex_flags & NFSEXP_SECURITY_LABEL) err = security_inode_getsecctx(d_inode(dentry), - &context, &contextlen); + &context); else err = -EOPNOTSUPP; contextsupport = (err == 0); @@ -2986,8 +2984,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp, #ifdef CONFIG_NFSD_V4_SECURITY_LABEL if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) { - status = nfsd4_encode_security_label(xdr, rqstp, context, - contextlen); + status = nfsd4_encode_security_label(xdr, rqstp, &context); if (status) goto out; } @@ -2999,10 +2996,8 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp, out: #ifdef CONFIG_NFSD_V4_SECURITY_LABEL - if (context) { - lsmcontext_init(&scaff, context, contextlen, 0); /*scaffolding*/ - security_release_secctx(&scaff); - } + if (context.context) + security_release_secctx(&context); #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */ kfree(acl); if (tempfh) { diff --git a/include/linux/security.h b/include/linux/security.h index 43f8a2660d37..02dc3b5ef57b 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -560,7 +560,7 @@ void security_release_secctx(struct lsmcontext *cp); void security_inode_invalidate_secctx(struct inode *inode); int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen); int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen); -int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen); +int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp); int security_locked_down(enum lockdown_reason what); #else /* CONFIG_SECURITY */ @@ -1399,7 +1399,8 @@ static inline int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 { return -EOPNOTSUPP; } -static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen) +static inline int security_inode_getsecctx(struct inode *inode, + struct lsmcontext *cp) { return -EOPNOTSUPP; } diff --git a/security/security.c b/security/security.c index 862f0bc2f114..ddbaf2073b02 100644 --- a/security/security.c +++ b/security/security.c @@ -2263,9 +2263,18 @@ int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen) } EXPORT_SYMBOL(security_inode_setsecctx); -int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen) +int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp) { - return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, ctx, ctxlen); + struct security_hook_list *hp; + + memset(cp, 0, sizeof(*cp)); + + hlist_for_each_entry(hp, &security_hook_heads.inode_getsecctx, list) { + cp->slot = hp->lsmid->slot; + return hp->hook.inode_getsecctx(inode, (void **)&cp->context, + &cp->len); + } + return -EOPNOTSUPP; } EXPORT_SYMBOL(security_inode_getsecctx);