From: Konstantin Andreev Date: Tue, 30 Sep 2025 12:31:53 +0000 (+0300) Subject: smack: /smack/doi: accept previously used values X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=33d589ed60ae433b483761987b85e0d24e54584e;p=thirdparty%2Fkernel%2Flinux.git 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: e114e473771c ("Smack: Simplified Mandatory Access Control Kernel") Signed-off-by: Konstantin Andreev Signed-off-by: Casey Schaufler --- diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index e611e0fb5620..8919e330d2f6 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -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; + + smk_netlabel_audit_set(&nai); - 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);