[PATCH v11 06/25] LSM: Use lsmblob in security_secctx_to_secid
John Johansen
john.johansen at canonical.com
Thu Nov 21 18:42:20 UTC 2019
On 11/13/19 10:19 AM, Casey Schaufler wrote:
> Change security_secctx_to_secid() to fill in a lsmblob instead
> of a u32 secid. Multiple LSMs may be able to interpret the
> string, and this allows for setting whichever secid is
> appropriate. In some cases there is scaffolding where other
> interfaces have yet to be converted.
>
> Reviewed-by: Kees Cook <keescook at chromium.org>
> Reviewed-by: John Johansen <john.johansen at canonical.com>
> Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
Acked-by: John Johansen <john.johansen at canonical.com>
> ---
> include/linux/security.h | 5 +++--
> kernel/cred.c | 4 +---
> net/netfilter/nft_meta.c | 13 ++++++-------
> net/netfilter/xt_SECMARK.c | 5 ++++-
> net/netlabel/netlabel_unlabeled.c | 14 ++++++++------
> security/security.c | 18 +++++++++++++++---
> 6 files changed, 37 insertions(+), 22 deletions(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index d57f400a307e..b69877a13efa 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -494,7 +494,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
> int security_netlink_send(struct sock *sk, struct sk_buff *skb);
> int security_ismaclabel(const char *name);
> int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
> -int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
> +int security_secctx_to_secid(const char *secdata, u32 seclen,
> + struct lsmblob *blob);
> void security_release_secctx(char *secdata, u32 seclen);
> void security_inode_invalidate_secctx(struct inode *inode);
> int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
> @@ -1300,7 +1301,7 @@ static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *secle
>
> static inline int security_secctx_to_secid(const char *secdata,
> u32 seclen,
> - u32 *secid)
> + struct lsmblob *blob)
> {
> return -EOPNOTSUPP;
> }
> diff --git a/kernel/cred.c b/kernel/cred.c
> index 846ac4b23c16..7fef90f3f10b 100644
> --- a/kernel/cred.c
> +++ b/kernel/cred.c
> @@ -756,14 +756,12 @@ EXPORT_SYMBOL(set_security_override);
> int set_security_override_from_ctx(struct cred *new, const char *secctx)
> {
> struct lsmblob blob;
> - u32 secid;
> int ret;
>
> - ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
> + ret = security_secctx_to_secid(secctx, strlen(secctx), &blob);
> if (ret < 0)
> return ret;
>
> - lsmblob_init(&blob, secid);
> return set_security_override(new, &blob);
> }
> EXPORT_SYMBOL(set_security_override_from_ctx);
> diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
> index 317e3a9e8c5b..7c49397c33fd 100644
> --- a/net/netfilter/nft_meta.c
> +++ b/net/netfilter/nft_meta.c
> @@ -617,21 +617,20 @@ static const struct nla_policy nft_secmark_policy[NFTA_SECMARK_MAX + 1] = {
>
> static int nft_secmark_compute_secid(struct nft_secmark *priv)
> {
> - u32 tmp_secid = 0;
> + struct lsmblob blob;
> int err;
>
> - err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &tmp_secid);
> + err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &blob);
> if (err)
> return err;
>
> - if (!tmp_secid)
> - return -ENOENT;
> -
> - err = security_secmark_relabel_packet(tmp_secid);
> + /* Using le[0] is scaffolding */
> + err = security_secmark_relabel_packet(blob.secid[0]);
> if (err)
> return err;
>
> - priv->secid = tmp_secid;
> + /* Using le[0] is scaffolding */
> + priv->secid = blob.secid[0];
> return 0;
> }
>
> diff --git a/net/netfilter/xt_SECMARK.c b/net/netfilter/xt_SECMARK.c
> index 2317721f3ecb..2d68416b4552 100644
> --- a/net/netfilter/xt_SECMARK.c
> +++ b/net/netfilter/xt_SECMARK.c
> @@ -45,13 +45,14 @@ secmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
>
> static int checkentry_lsm(struct xt_secmark_target_info *info)
> {
> + struct lsmblob blob;
> int err;
>
> info->secctx[SECMARK_SECCTX_MAX - 1] = '\0';
> info->secid = 0;
>
> err = security_secctx_to_secid(info->secctx, strlen(info->secctx),
> - &info->secid);
> + &blob);
> if (err) {
> if (err == -EINVAL)
> pr_info_ratelimited("invalid security context \'%s\'\n",
> @@ -59,6 +60,8 @@ static int checkentry_lsm(struct xt_secmark_target_info *info)
> return err;
> }
>
> + /* scaffolding during the transition */
> + info->secid = blob.secid[0];
> if (!info->secid) {
> pr_info_ratelimited("unable to map security context \'%s\'\n",
> info->secctx);
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index d2e4ab8d1cb1..7a5a87f15736 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -881,7 +881,7 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
> void *addr;
> void *mask;
> u32 addr_len;
> - u32 secid;
> + struct lsmblob blob;
> struct netlbl_audit audit_info;
>
> /* Don't allow users to add both IPv4 and IPv6 addresses for a
> @@ -905,12 +905,13 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
> ret_val = security_secctx_to_secid(
> nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
> nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
> - &secid);
> + &blob);
> if (ret_val != 0)
> return ret_val;
>
> + /* scaffolding with the [0] */
> return netlbl_unlhsh_add(&init_net,
> - dev_name, addr, mask, addr_len, secid,
> + dev_name, addr, mask, addr_len, blob.secid[0],
> &audit_info);
> }
>
> @@ -932,7 +933,7 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
> void *addr;
> void *mask;
> u32 addr_len;
> - u32 secid;
> + struct lsmblob blob;
> struct netlbl_audit audit_info;
>
> /* Don't allow users to add both IPv4 and IPv6 addresses for a
> @@ -954,12 +955,13 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
> ret_val = security_secctx_to_secid(
> nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
> nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
> - &secid);
> + &blob);
> if (ret_val != 0)
> return ret_val;
>
> + /* scaffolding with the [0] */
> return netlbl_unlhsh_add(&init_net,
> - NULL, addr, mask, addr_len, secid,
> + NULL, addr, mask, addr_len, blob.secid[0],
> &audit_info);
> }
>
> diff --git a/security/security.c b/security/security.c
> index 55837706e3ef..32bb5383de9b 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1970,10 +1970,22 @@ int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
> }
> EXPORT_SYMBOL(security_secid_to_secctx);
>
> -int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
> +int security_secctx_to_secid(const char *secdata, u32 seclen,
> + struct lsmblob *blob)
> {
> - *secid = 0;
> - return call_int_hook(secctx_to_secid, 0, secdata, seclen, secid);
> + struct security_hook_list *hp;
> + int rc;
> +
> + lsmblob_init(blob, 0);
> + hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
> + if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
> + continue;
> + rc = hp->hook.secctx_to_secid(secdata, seclen,
> + &blob->secid[hp->lsmid->slot]);
> + if (rc != 0)
> + return rc;
> + }
> + return 0;
> }
> EXPORT_SYMBOL(security_secctx_to_secid);
>
>
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