[PATCH v3 5/5] Audit: Add record for multiple object contexts
From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2025-03-19 22:38:08
Also in:
lkml, selinux
Subsystem:
audit subsystem, the rest · Maintainers:
Paul Moore, Eric Paris, Linus Torvalds
Create a new audit record AUDIT_MAC_OBJ_CONTEXTS.
An example of the MAC_OBJ_CONTEXTS (1424) record is:
type=MAC_OBJ_CONTEXTS[1424]
msg=audit(1601152467.009:1050):
obj_selinux=unconfined_u:object_r:user_home_t:s0
When an audit event includes a AUDIT_MAC_OBJ_CONTEXTS record
the "obj=" field in other records in the event will be "obj=?".
An AUDIT_MAC_OBJ_CONTEXTS record is supplied when the system has
multiple security modules that may make access decisions based
on an object security context.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
include/linux/audit.h | 6 +++++
include/uapi/linux/audit.h | 1 +
kernel/audit.c | 51 +++++++++++++++++++++++++++++++++++++-
kernel/auditsc.c | 45 ++++++++-------------------------
4 files changed, 68 insertions(+), 35 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 3402e3ca43c6..8fdfa2721273 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h@@ -188,6 +188,7 @@ extern void audit_log_path_denied(int type, extern void audit_log_lost(const char *message); extern int audit_log_subj_ctx(struct audit_buffer *ab, struct lsm_prop *prop); +extern int audit_log_obj_ctx(struct audit_buffer *ab, struct lsm_prop *prop); extern int audit_log_task_context(struct audit_buffer *ab); extern void audit_log_task_info(struct audit_buffer *ab);
@@ -255,6 +256,11 @@ static inline int audit_log_subj_ctx(struct audit_buffer *ab, { return 0; } +static inline int audit_log_obj_ctx(struct audit_buffer *ab, + struct lsm_prop *prop) +{ + return 0; +} static inline int audit_log_task_context(struct audit_buffer *ab) { return 0;
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 5ebb5d80363d..8ca58144bcc6 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h@@ -147,6 +147,7 @@ #define AUDIT_IPE_CONFIG_CHANGE 1421 /* IPE config change */ #define AUDIT_IPE_POLICY_LOAD 1422 /* IPE policy load */ #define AUDIT_MAC_TASK_CONTEXTS 1423 /* Multiple LSM task contexts */ +#define AUDIT_MAC_OBJ_CONTEXTS 1424 /* Multiple LSM objext 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 8ce453f6dc7d..69db0ee09a3f 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c@@ -1133,7 +1133,6 @@ static int is_audit_feature_set(int i) return af.features & AUDIT_FEATURE_TO_MASK(i); } - static int audit_get_feature(struct sk_buff *skb) { u32 seq;
@@ -2324,6 +2323,56 @@ int audit_log_task_context(struct audit_buffer *ab) } EXPORT_SYMBOL(audit_log_task_context); +int audit_log_obj_ctx(struct audit_buffer *ab, struct lsm_prop *prop) +{ + int i; + int rc; + int error = 0; + char *space = ""; + struct lsm_context context; + + if (audit_secctx_cnt < 2) { + error = security_lsmprop_to_secctx(prop, &context, + LSM_ID_UNDEF); + if (error < 0) { + if (error != -EINVAL) + goto error_path; + return error; + } + audit_log_format(ab, " obj=%s", context.context); + security_release_secctx(&context); + return 0; + } + audit_log_format(ab, " obj=?"); + error = audit_buffer_aux_new(ab, AUDIT_MAC_OBJ_CONTEXTS); + if (error) + goto error_path; + + for (i = 0; i < audit_secctx_cnt; i++) { + rc = security_lsmprop_to_secctx(prop, &context, + audit_lsms[i]->id); + if (rc < 0) { + audit_log_format(ab, "%sobj_%s=?", space, + audit_lsms[i]->name); + if (rc != -EINVAL) + audit_panic("error in audit_log_obj_ctx"); + error = rc; + } else { + audit_log_format(ab, "%sobj_%s=%s", space, + audit_lsms[i]->name, context.context); + security_release_secctx(&context); + } + space = " "; + } + + audit_buffer_aux_end(ab); + return error; + +error_path: + audit_panic("error in audit_log_obj_ctx"); + return error; +} + void audit_log_d_path_exe(struct audit_buffer *ab, struct mm_struct *mm) {
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index dc3f7e9666f2..e39d7be20c29 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c@@ -1098,7 +1098,6 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, char *comm) { struct audit_buffer *ab; - struct lsm_context ctx; int rc = 0; ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
@@ -1108,15 +1107,9 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid, from_kuid(&init_user_ns, auid), from_kuid(&init_user_ns, uid), sessionid); - if (lsmprop_is_set(prop)) { - if (security_lsmprop_to_secctx(prop, &ctx, LSM_ID_UNDEF) < 0) { - audit_log_format(ab, " obj=(none)"); - rc = 1; - } else { - audit_log_format(ab, " obj=%s", ctx.context); - security_release_secctx(&ctx); - } - } + if (lsmprop_is_set(prop) && audit_log_obj_ctx(ab, prop)) + rc = 1; + audit_log_format(ab, " ocomm="); audit_log_untrustedstring(ab, comm); audit_log_end(ab);
@@ -1392,16 +1385,8 @@ static void show_special(struct audit_context *context, int *call_panic) from_kgid(&init_user_ns, context->ipc.gid), context->ipc.mode); if (lsmprop_is_set(&context->ipc.oprop)) { - struct lsm_context lsmctx; - - if (security_lsmprop_to_secctx(&context->ipc.oprop, - &lsmctx, - LSM_ID_UNDEF) < 0) { + if (audit_log_obj_ctx(ab, &context->ipc.oprop)) *call_panic = 1; - } else { - audit_log_format(ab, " obj=%s", lsmctx.context); - security_release_secctx(&lsmctx); - } } if (context->ipc.has_perm) { audit_log_end(ab);
@@ -1558,18 +1543,9 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n, from_kgid(&init_user_ns, n->gid), MAJOR(n->rdev), MINOR(n->rdev)); - if (lsmprop_is_set(&n->oprop)) { - struct lsm_context ctx; - - if (security_lsmprop_to_secctx(&n->oprop, &ctx, - LSM_ID_UNDEF) < 0) { - if (call_panic) - *call_panic = 2; - } else { - audit_log_format(ab, " obj=%s", ctx.context); - security_release_secctx(&ctx); - } - } + if (lsmprop_is_set(&n->oprop) && + audit_log_obj_ctx(ab, &n->oprop)) + *call_panic = 2; /* log the audit_names record type */ switch (n->type) {
@@ -1780,15 +1756,16 @@ static void audit_log_exit(void) axs->target_sessionid[i], &axs->target_ref[i], axs->target_comm[i])) - call_panic = 1; + call_panic = 1; } if (context->target_pid && audit_log_pid_context(context, context->target_pid, context->target_auid, context->target_uid, context->target_sessionid, - &context->target_ref, context->target_comm)) - call_panic = 1; + &context->target_ref, + context->target_comm)) + call_panic = 1; if (context->pwd.dentry && context->pwd.mnt) { ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD);
--
2.47.0