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This provides the information about which LSM created the context so that security_release_secctx() can use the correct hook. A lsmcontext is used within kernfs to store the security information as well. Signed-off-by: Casey Schaufler Reviewed-by: Kees Cook Reviewed-by: John Johansen --- fs/kernfs/dir.c | 8 ++------ fs/kernfs/inode.c | 34 ++++++++++++---------------------- fs/kernfs/kernfs-internal.h | 3 +-- fs/nfsd/nfs4xdr.c | 23 +++++++++-------------- include/linux/security.h | 5 +++-- security/security.c | 13 +++++++++++-- 6 files changed, 38 insertions(+), 48 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 92afad387237..1d000289d8b7 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -532,12 +532,8 @@ void kernfs_put(struct kernfs_node *kn) kfree_const(kn->name); if (kn->iattr) { - struct lsmcontext scaff; /* scaffolding */ - if (kn->iattr->ia_secdata) { - lsmcontext_init(&scaff, kn->iattr->ia_secdata, - kn->iattr->ia_secdata_len, 0); - security_release_secctx(&scaff); - } + if (kn->iattr->ia_context.context) + security_release_secctx(&kn->iattr->ia_context); simple_xattrs_free(&kn->iattr->xattrs); kmem_cache_free(kernfs_iattrs_cache, kn->iattr); } diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index 02cde9dac5ee..ffbf7863306d 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -135,21 +135,14 @@ int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr) return error; } -static int kernfs_node_setsecdata(struct kernfs_iattrs *attrs, void **secdata, - u32 *secdata_len) +static void kernfs_node_setsecdata(struct kernfs_iattrs *attrs, + struct lsmcontext *cp) { - void *old_secdata; - size_t old_secdata_len; + struct lsmcontext old_context; - old_secdata = attrs->ia_secdata; - old_secdata_len = attrs->ia_secdata_len; - - attrs->ia_secdata = *secdata; - attrs->ia_secdata_len = *secdata_len; - - *secdata = old_secdata; - *secdata_len = old_secdata_len; - return 0; + old_context = attrs->ia_context; + attrs->ia_context = *cp; + *cp = old_context; } ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size) @@ -192,8 +185,8 @@ static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode) * persistent copy in kernfs_node. */ set_inode_attr(inode, &attrs->ia_iattr); - security_inode_notifysecctx(inode, attrs->ia_secdata, - attrs->ia_secdata_len); + security_inode_notifysecctx(inode, attrs->ia_context.context, + attrs->ia_context.len); } if (kernfs_type(kn) == KERNFS_DIR) @@ -350,8 +343,6 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler, struct kernfs_node *kn = inode->i_private; struct kernfs_iattrs *attrs; struct lsmcontext context; - void *secdata; - u32 secdata_len = 0; int error; attrs = kernfs_iattrs(kn); @@ -361,18 +352,17 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler, error = security_inode_setsecurity(inode, suffix, value, size, flags); if (error) return error; - error = security_inode_getsecctx(inode, &secdata, &secdata_len); + error = security_inode_getsecctx(inode, &context); if (error) return error; mutex_lock(&kernfs_mutex); - error = kernfs_node_setsecdata(attrs, &secdata, &secdata_len); + kernfs_node_setsecdata(attrs, &context); mutex_unlock(&kernfs_mutex); - if (secdata) { - lsmcontext_init(&context, secdata, secdata_len, 0); + if (context.context) security_release_secctx(&context); - } + return error; } diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 0b7d197a904c..844a028d282f 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -21,8 +21,7 @@ struct kernfs_iattrs { struct iattr ia_iattr; - void *ia_secdata; - u32 ia_secdata_len; + struct lsmcontext ia_context; struct simple_xattrs xattrs; }; diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index bb3db033e144..1209083565dd 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -2304,11 +2304,11 @@ 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; @@ -2318,13 +2318,13 @@ 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 @@ -2420,9 +2420,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp, __be32 status; int err; struct nfs4_acl *acl = NULL; - struct lsmcontext scaff; /* scaffolding */ - void *context = NULL; - int contextlen; + struct lsmcontext context; bool contextsupport = false; struct nfsd4_compoundres *resp = rqstp->rq_resp; u32 minorversion = resp->cstate.minorversion; @@ -2479,7 +2477,7 @@ 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); @@ -2908,8 +2906,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp, } 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; } @@ -2920,10 +2917,8 @@ 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 2a2785a4e752..bfdb06bc5466 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -485,7 +485,7 @@ 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); #else /* CONFIG_SECURITY */ static inline int call_lsm_notifier(enum lsm_event event, void *data) @@ -1286,7 +1286,8 @@ 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 842ac65abc08..b2ffcd1f3057 100644 --- a/security/security.c +++ b/security/security.c @@ -2139,9 +2139,18 @@ 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); + int *display = current->security; + struct security_hook_list *hp; + + hlist_for_each_entry(hp, &security_hook_heads.inode_getsecctx, list) + if (*display == 0 || *display == hp->slot) { + cp->slot = hp->slot; + return hp->hook.inode_getsecctx(inode, + (void **)&cp->context, &cp->len); + } + return -EOPNOTSUPP; } EXPORT_SYMBOL(security_inode_getsecctx);