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smack: /smack/doi: accept previously used values

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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: e114e47377 ("Smack: Simplified Mandatory Access Control Kernel")

Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
This commit is contained in:
Konstantin Andreev 2025-09-30 15:31:53 +03:00 • committed by Casey Schaufler
parent 19c013e155
commit 33d589ed60
1 changed files with 45 additions and 26 deletions
Download patch file Download diff file Expand all files Collapse all files

71
security/smack/smackfs.c
View file

@ -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;
mutex_lock(&smk_cipso_doi_lock);
if (smk_cipso_doi_value == ndoi)
goto clr_doi_lock;
smk_netlabel_audit_set(&nai);
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);
doip = kmalloc(sizeof(struct cipso_v4_doi), GFP_KERNEL | __GFP_NOFAIL);
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);