Re: [PATCH v25 17/25] LSM: Use lsmcontext in security_inode_getsecctx
From: Chuck Lever III <hidden>
Date: 2021-03-12 16:28:13
Also in:
linux-nfs, lkml, selinux
Hi Casey-
On Mar 9, 2021, at 9:42 AM, Casey Schaufler [off-list ref] wrote: 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 <redacted> Acked-by: Paul Moore <paul@paul-moore.com> Reviewed-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Cc: linux-nfs@vger.kernel.org
For the NFSD hunks in 15/25 and 17/25: Acked-by: Chuck Lever <redacted>
quoted hunk ↗ jump to hunk
--- 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 afccc4f257d0..a796268ec757 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c@@ -2727,11 +2727,11 @@ 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;@@ -2741,13 +2741,13 @@ 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@@ -2844,9 +2844,7 @@ 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;@@ -2904,7 +2902,7 @@ 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);@@ -3324,8 +3322,7 @@ 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; }@@ -3346,10 +3343,8 @@ 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 d0e1b6ba330d..9dcc910036f4 100644 --- a/include/linux/security.h +++ b/include/linux/security.h@@ -582,7 +582,7 @@ 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 */@@ -1442,7 +1442,8 @@ 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 73fb5c6c4cf8..b88f916e0698 100644 --- a/security/security.c +++ b/security/security.c@@ -2337,9 +2337,18 @@ 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); -- 2.29.2
-- Chuck Lever