Commit 33d589ed authored by Konstantin Andreev's avatar Konstantin Andreev Committed by Casey Schaufler
Browse files

smack: /smack/doi: accept previously used values 



Writing to /smack/doi a value that has ever been
written there in the past disables networking for
non-ambient labels.
E.g.

    # cat /smack/doi
    3
    # netlabelctl -p cipso list
    Configured CIPSO mappings (1)
     DOI value : 3
       mapping type : PASS_THROUGH
    # netlabelctl -p map list
    Configured NetLabel domain mappings (3)
     domain: "_" (IPv4)
       protocol: UNLABELED
     domain: DEFAULT (IPv4)
       protocol: CIPSO, DOI = 3
     domain: DEFAULT (IPv6)
       protocol: UNLABELED

    # cat /smack/ambient
    _
    # cat /proc/$$/attr/smack/current
    _
    # ping -c1 10.1.95.12
    64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.964 ms
    # echo foo >/proc/$$/attr/smack/current
    # ping -c1 10.1.95.12
    64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.956 ms
    unknown option 86

    # echo 4 >/smack/doi
    # echo 3 >/smack/doi
!>  [  214.050395] smk_cipso_doi:691 cipso add rc = -17
    # echo 3 >/smack/doi
!>  [  249.402261] smk_cipso_doi:678 remove rc = -2
!>  [  249.402261] smk_cipso_doi:691 cipso add rc = -17

    # ping -c1 10.1.95.12
!!> ping: 10.1.95.12: Address family for hostname not supported

    # echo _ >/proc/$$/attr/smack/current
    # ping -c1 10.1.95.12
    64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.617 ms

This happens because Smack keeps decommissioned DOIs,
fails to re-add them, and consequently refuses to add
the “default” domain map:

    # netlabelctl -p cipso list
    Configured CIPSO mappings (2)
     DOI value : 3
       mapping type : PASS_THROUGH
     DOI value : 4
       mapping type : PASS_THROUGH
    # netlabelctl -p map list
    Configured NetLabel domain mappings (2)
     domain: "_" (IPv4)
       protocol: UNLABELED
!>  (no ipv4 map for default domain here)
     domain: DEFAULT (IPv6)
       protocol: UNLABELED

Fix by clearing decommissioned DOI definitions and
serializing concurrent DOI updates with a new lock.

Also:
- allow /smack/doi to live unconfigured, since
  adding a map (netlbl_cfg_cipsov4_map_add) may fail.
  CIPSO_V4_DOI_UNKNOWN(0) indicates the unconfigured DOI
- add new DOI before removing the old default map,
  so the old map remains if the add fails

(2008-02-04, Casey Schaufler)
Fixes: e114e473 ("Smack: Simplified Mandatory Access Control Kernel")

Signed-off-by: default avatarKonstantin Andreev <andreev@swemel.ru>
Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
parent 19c013e1

security/smack/smackfs.c

+45 −26
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ enum smk_inos { 
static DEFINE_MUTEX(smack_cipso_lock);

static DEFINE_MUTEX(smack_ambient_lock);

static DEFINE_MUTEX(smk_net4addr_lock);

static DEFINE_MUTEX(smk_cipso_doi_lock);

#if IS_ENABLED(CONFIG_IPV6)

static DEFINE_MUTEX(smk_net6addr_lock);

#endif /* CONFIG_IPV6 */
@@ -141,7 +142,7 @@ struct smack_parsed_rule { 
	int			smk_access2;

};



static u32 smk_cipso_doi_value = SMACK_CIPSO_DOI_DEFAULT;

static u32 smk_cipso_doi_value = CIPSO_V4_DOI_UNKNOWN;



/*

 * Values for parsing cipso rules
@@ -663,43 +664,60 @@ static const struct file_operations smk_load_ops = { 
};



/**

 * smk_cipso_doi - initialize the CIPSO domain

 * smk_cipso_doi - set netlabel maps

 * @ndoi: new value for our CIPSO DOI

 * @gfp_flags: kmalloc allocation context

 */

static void smk_cipso_doi(void)

static int

smk_cipso_doi(u32 ndoi, gfp_t gfp_flags)

{

	int rc;

	int rc = 0;

	struct cipso_v4_doi *doip;

	struct netlbl_audit nai;



	smk_netlabel_audit_set(&nai);

	mutex_lock(&smk_cipso_doi_lock);



	rc = netlbl_cfg_map_del(NULL, PF_INET, NULL, NULL, &nai);

	if (rc != 0)

		printk(KERN_WARNING "%s:%d remove rc = %d\n",

		       __func__, __LINE__, rc);

	if (smk_cipso_doi_value == ndoi)

		goto clr_doi_lock;



	doip = kmalloc(sizeof(struct cipso_v4_doi), GFP_KERNEL | __GFP_NOFAIL);

	smk_netlabel_audit_set(&nai);



	doip = kmalloc(sizeof(struct cipso_v4_doi), gfp_flags);

	if (!doip) {

		rc = -ENOMEM;

		goto clr_doi_lock;

	}

	doip->map.std = NULL;

	doip->doi = smk_cipso_doi_value;

	doip->doi = ndoi;

	doip->type = CIPSO_V4_MAP_PASS;

	doip->tags[0] = CIPSO_V4_TAG_RBITMAP;

	for (rc = 1; rc < CIPSO_V4_TAG_MAXCNT; rc++)

		doip->tags[rc] = CIPSO_V4_TAG_INVALID;



	rc = netlbl_cfg_cipsov4_add(doip, &nai);

	if (rc != 0) {

		printk(KERN_WARNING "%s:%d cipso add rc = %d\n",

		       __func__, __LINE__, rc);

	if (rc) {

		kfree(doip);

		return;

		goto clr_doi_lock;

	}

	rc = netlbl_cfg_cipsov4_map_add(doip->doi, NULL, NULL, NULL, &nai);

	if (rc != 0) {

		printk(KERN_WARNING "%s:%d map add rc = %d\n",

		       __func__, __LINE__, rc);

		netlbl_cfg_cipsov4_del(doip->doi, &nai);

		return;



	if (smk_cipso_doi_value != CIPSO_V4_DOI_UNKNOWN) {

		rc = netlbl_cfg_map_del(NULL, PF_INET, NULL, NULL, &nai);

		if (rc && rc != -ENOENT)

			goto clr_ndoi_def;



		netlbl_cfg_cipsov4_del(smk_cipso_doi_value, &nai);

	}



	rc = netlbl_cfg_cipsov4_map_add(ndoi, NULL, NULL, NULL, &nai);

	if (rc) {

		smk_cipso_doi_value = CIPSO_V4_DOI_UNKNOWN; // no default map

clr_ndoi_def:	netlbl_cfg_cipsov4_del(ndoi, &nai);

	} else

		smk_cipso_doi_value = ndoi;



clr_doi_lock:

	mutex_unlock(&smk_cipso_doi_lock);

	return rc;

}



/**
@@ -1599,11 +1617,8 @@ static ssize_t smk_write_doi(struct file *file, const char __user *buf, 


	if (u == CIPSO_V4_DOI_UNKNOWN || u > U32_MAX)

		return -EINVAL;

	smk_cipso_doi_value = u;



	smk_cipso_doi();



	return count;

	return smk_cipso_doi(u, GFP_KERNEL) ? : count;

}



static const struct file_operations smk_doi_ops = {
@@ -2984,6 +2999,7 @@ int __init init_smk_fs(void) 
{

	int err;

	int rc;

	struct netlbl_audit nai;



	if (smack_enabled == 0)

		return 0;
@@ -3002,7 +3018,10 @@ int __init init_smk_fs(void) 
		}

	}



	smk_cipso_doi();

	smk_netlabel_audit_set(&nai);

	(void) netlbl_cfg_map_del(NULL, PF_INET, NULL, NULL, &nai);

	(void) smk_cipso_doi(SMACK_CIPSO_DOI_DEFAULT,

			     GFP_KERNEL | __GFP_NOFAIL);

	smk_unlbl_ambient(NULL);



	rc = smack_populate_secattr(&smack_known_floor);