Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Casey Schaufler <> | Subject | [PATCH v39 24/42] Audit: Add record for multiple task security contexts | Date | Fri, 15 Dec 2023 14:16:18 -0800 |
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Create a new audit record AUDIT_MAC_TASK_CONTEXTS. An example of the MAC_TASK_CONTEXTS (1420) record is:
type=MAC_TASK_CONTEXTS[1420] msg=audit(1600880931.832:113) subj_apparmor=unconfined subj_smack=_
When an audit event includes a AUDIT_MAC_TASK_CONTEXTS record the "subj=" field in other records in the event will be "subj=?". An AUDIT_MAC_TASK_CONTEXTS record is supplied when the system has multiple security modules that may make access decisions based on a subject security context.
Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> --- include/linux/lsm_hooks.h | 2 ++ include/linux/security.h | 1 + include/uapi/linux/audit.h | 1 + kernel/audit.c | 45 ++++++++++++++++++++++++++++++++------ security/apparmor/lsm.c | 1 + security/bpf/hooks.c | 1 + security/security.c | 3 +++ security/selinux/hooks.c | 1 + security/smack/smack_lsm.c | 1 + 9 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index efd4a0655159..605aaf38c3f5 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -47,12 +47,14 @@ struct security_hook_heads { * struct lsm_id - Identify a Linux Security Module. * @lsm: name of the LSM, must be approved by the LSM maintainers * @id: LSM ID number from uapi/linux/lsm.h + * @lsmblob: indicates the LSM has an entry in struct lsmblob * * Contains the information that identifies the LSM. */ struct lsm_id { const char *name; u64 id; + bool lsmblob; }; /* diff --git a/include/linux/security.h b/include/linux/security.h index 360a454d5f8e..947cb3a35db4 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -192,6 +192,7 @@ struct lsmblob { extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1]; extern u32 lsm_active_cnt; +extern u32 lsm_blob_cnt; extern const struct lsm_id *lsm_idlist[]; /* These functions are in security/commoncap.c */ diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index d676ed2b246e..dc045164b86b 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -143,6 +143,7 @@ #define AUDIT_MAC_UNLBL_STCDEL 1417 /* NetLabel: del a static label */ #define AUDIT_MAC_CALIPSO_ADD 1418 /* NetLabel: add CALIPSO DOI entry */ #define AUDIT_MAC_CALIPSO_DEL 1419 /* NetLabel: del CALIPSO DOI entry */ +#define AUDIT_MAC_TASK_CONTEXTS 1420 /* Multiple LSM task contexts */ #define AUDIT_FIRST_KERN_ANOM_MSG 1700 #define AUDIT_LAST_KERN_ANOM_MSG 1799 diff --git a/kernel/audit.c b/kernel/audit.c index b194494c4dc4..9d971fa96c0e 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -54,6 +54,7 @@ #include <net/netlink.h> #include <linux/skbuff.h> #include <linux/security.h> +#include <linux/lsm_hooks.h> #include <linux/freezer.h> #include <linux/pid_namespace.h> #include <net/netns/generic.h> @@ -2228,21 +2229,51 @@ int audit_log_task_context(struct audit_buffer *ab) { struct lsmcontext ctx; struct lsmblob blob; + bool space = false; int error; + int i; security_current_getlsmblob_subj(&blob); if (!lsmblob_is_set(&blob)) return 0; - error = security_lsmblob_to_secctx(&blob, &ctx, LSM_ID_UNDEF); - if (error < 0) { - if (error != -EINVAL) - goto error_path; + if (lsm_blob_cnt < 2) { + error = security_lsmblob_to_secctx(&blob, &ctx, LSM_ID_UNDEF); + if (error < 0) { + if (error != -EINVAL) + goto error_path; + return 0; + } + audit_log_format(ab, " subj=%s", ctx.context); + security_release_secctx(&ctx); return 0; } - - audit_log_format(ab, " subj=%s", ctx.context); - security_release_secctx(&ctx); + /* Multiple LSMs provide contexts. Include an aux record. */ + audit_log_format(ab, " subj=?"); + error = audit_buffer_aux_new(ab, AUDIT_MAC_TASK_CONTEXTS); + if (error) + goto error_path; + + for (i = 0; i < lsm_active_cnt; i++) { + if (!lsm_idlist[i]->lsmblob) + continue; + error = security_lsmblob_to_secctx(&blob, &ctx, + lsm_idlist[i]->id); + if (error < 0) { + if (error == -EOPNOTSUPP) + continue; + audit_log_format(ab, "%ssubj_%s=?", space ? " " : "", + lsm_idlist[i]->name); + if (error != -EINVAL) + audit_panic("error in audit_log_task_context"); + } else { + audit_log_format(ab, "%ssubj_%s=%s", space ? " " : "", + lsm_idlist[i]->name, ctx.context); + security_release_secctx(&ctx); + } + space = true; + } + audit_buffer_aux_end(ab); return 0; error_path: diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index b5f3beb26d5a..075942b253ae 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -1447,6 +1447,7 @@ struct lsm_blob_sizes apparmor_blob_sizes __ro_after_init = { static const struct lsm_id apparmor_lsmid = { .name = "apparmor", .id = LSM_ID_APPARMOR, + .lsmblob = true, }; static struct security_hook_list apparmor_hooks[] __ro_after_init = { diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c index 57b9ffd53c98..2da40774dd20 100644 --- a/security/bpf/hooks.c +++ b/security/bpf/hooks.c @@ -19,6 +19,7 @@ static struct security_hook_list bpf_lsm_hooks[] __ro_after_init = { static const struct lsm_id bpf_lsmid = { .name = "bpf", .id = LSM_ID_BPF, + .lsmblob = true, }; static int __init bpf_lsm_init(void) diff --git a/security/security.c b/security/security.c index 444051575793..8ff6cef26e6c 100644 --- a/security/security.c +++ b/security/security.c @@ -269,6 +269,7 @@ static void __init initialize_lsm(struct lsm_info *lsm) * Current index to use while initializing the lsm id list. */ u32 lsm_active_cnt __ro_after_init; +u32 lsm_blob_cnt __ro_after_init; const struct lsm_id *lsm_idlist[LSM_CONFIG_COUNT]; /** @@ -599,6 +600,8 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count, if (lsm_active_cnt >= LSM_CONFIG_COUNT) panic("%s Too many LSMs registered.\n", __func__); lsm_idlist[lsm_active_cnt++] = lsmid; + if (lsmid->lsmblob) + lsm_blob_cnt++; } for (i = 0; i < count; i++) { diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index ed4237223959..656f25337334 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -7092,6 +7092,7 @@ static int selinux_uring_cmd(struct io_uring_cmd *ioucmd) static const struct lsm_id selinux_lsmid = { .name = "selinux", .id = LSM_ID_SELINUX, + .lsmblob = true, }; /* diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index a58e2c14f120..a9ab31a40e36 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -5069,6 +5069,7 @@ struct lsm_blob_sizes smack_blob_sizes __ro_after_init = { static const struct lsm_id smack_lsmid = { .name = "smack", .id = LSM_ID_SMACK, + .lsmblob = true, }; static struct security_hook_list smack_hooks[] __ro_after_init = { -- 2.41.0
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