Re: [PATCH v28 22/25] Audit: Add record for multiple process LSM attributes

Create a new audit record type to contain the subject information when there are multiple security modules that require such data. This record is linked with the same timestamp and serial number using the audit_alloc_local() mechanism. The record is produced only in cases where there is more than one security module with a process "context". In cases where this record is produced the subj= fields of other records in the audit event will be set to "subj=?". An example of the MAC_TASK_CONTEXTS (1420) record is: type=UNKNOWN[1420] msg=audit(1600880931.832:113) subj_apparmor="=unconfined" subj_smack="_" There will be a subj_$LSM= entry for each security module LSM that supports the secid_to_secctx and secctx_to_secid hooks. The BPF security module implements secid/secctx translation hooks, so it has to be considered to provide a secctx even though it may not actually do so. Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com&gt; To: paul(a)paul-moore.com To: linux-audit(a)redhat.com To: rgb(a)redhat.com Cc: netdev(a)vger.kernel.org --- drivers/android/binder.c | 2 +- include/linux/audit.h | 16 +++++ include/linux/security.h | 16 ++++- include/net/netlabel.h | 2 +- include/net/scm.h | 2 +- include/net/xfrm.h | 13 +++- include/uapi/linux/audit.h | 1 + kernel/audit.c | 90 +++++++++++++++++++------ kernel/auditfilter.c | 5 +- kernel/auditsc.c | 27 ++++++-- net/ipv4/ip_sockglue.c | 2 +- net/netfilter/nf_conntrack_netlink.c | 4 +- net/netfilter/nf_conntrack_standalone.c | 2 +- net/netfilter/nfnetlink_queue.c | 2 +- net/netlabel/netlabel_unlabeled.c | 21 +++--- net/netlabel/netlabel_user.c | 14 ++-- net/netlabel/netlabel_user.h | 6 +- net/xfrm/xfrm_policy.c | 8 ++- net/xfrm/xfrm_state.c | 18 +++-- security/integrity/ima/ima_api.c | 6 +- security/integrity/integrity_audit.c | 5 +- security/security.c | 46 ++++++++----- security/smack/smackfs.c | 3 +- 23 files changed, 221 insertions(+), 90 deletions(-) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 2c3a2348a144..3520caa0260c 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2722,7 +2722,7 @@ static void binder_transaction(struct binder_proc *proc, * case well anyway. */ security_task_getsecid_obj(proc->tsk, &blob); - ret = security_secid_to_secctx(&blob, &lsmctx); + ret = security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_DISPLAY); if (ret) { return_error = BR_FAILED_REPLY; return_error_param = ret; diff --git a/include/linux/audit.h b/include/linux/audit.h index 97cd7471e572..85eb87f6f92d 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -291,6 +291,7 @@ extern int audit_alloc(struct task_struct *task); extern void __audit_free(struct task_struct *task); extern struct audit_context *audit_alloc_local(gfp_t gfpflags); extern void audit_free_context(struct audit_context *context); +extern void audit_free_local(struct audit_context *context); extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1, unsigned long a2, unsigned long a3); extern void __audit_syscall_exit(int ret_success, long ret_value); @@ -386,6 +387,19 @@ static inline void audit_ptrace(struct task_struct *t) __audit_ptrace(t); } +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp) +{ + struct audit_context *context = audit_context(); + + if (context) + return context; + + if (lsm_multiple_contexts()) + return audit_alloc_local(gfp); + + return NULL; +}

/* Private API (for audit.c only) */ extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp); extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode); @@ -560,6 +574,8 @@ extern int audit_signals; } static inline void audit_free_context(struct audit_context *context) { } +static inline void audit_free_local(struct audit_context *context) +{ } static inline int audit_alloc(struct task_struct *task) { return 0; diff --git a/include/linux/security.h b/include/linux/security.h index 3e9743118fb9..b3cf68cf2bd6 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -182,6 +182,8 @@ struct lsmblob { #define LSMBLOB_INVALID -1 /* Not a valid LSM slot number */ #define LSMBLOB_NEEDED -2 /* Slot requested on initialization */ #define LSMBLOB_NOT_NEEDED -3 /* Slot not requested */ +#define LSMBLOB_DISPLAY -4 /* Use the "display" slot */ +#define LSMBLOB_FIRST -5 /* Use the default "display" slot */ /** * lsmblob_init - initialize an lsmblob structure @@ -248,6 +250,15 @@ static inline u32 lsmblob_value(const struct lsmblob *blob) return 0; } +static inline bool lsm_multiple_contexts(void) +{ +#ifdef CONFIG_SECURITY + return lsm_slot_to_name(1) != NULL; +#else + return false; +#endif +} + /* These functions are in security/commoncap.c */ extern int cap_capable(const struct cred *cred, struct user_namespace *ns, int cap, unsigned int opts); @@ -578,7 +589,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value, size_t size); int security_netlink_send(struct sock *sk, struct sk_buff *skb); int security_ismaclabel(const char *name); -int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp); +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp, + int display); int security_secctx_to_secid(const char *secdata, u32 seclen, struct lsmblob *blob); void security_release_secctx(struct lsmcontext *cp); @@ -1433,7 +1445,7 @@ static inline int security_ismaclabel(const char *name) } static inline int security_secid_to_secctx(struct lsmblob *blob, - struct lsmcontext *cp) + struct lsmcontext *cp, int display) { return -EOPNOTSUPP; } diff --git a/include/net/netlabel.h b/include/net/netlabel.h index 73fc25b4042b..216cb1ffc8f0 100644 --- a/include/net/netlabel.h +++ b/include/net/netlabel.h @@ -97,7 +97,7 @@ struct calipso_doi; /* NetLabel audit information */ struct netlbl_audit { - u32 secid; + struct lsmblob lsmdata; kuid_t loginuid; unsigned int sessionid; };

diff --git a/include/net/scm.h b/include/net/scm.h index b77a52f93389..f4d567d4885e 100644 --- a/include/net/scm.h +++ b/include/net/scm.h @@ -101,7 +101,7 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc * and the infrastructure will know which it is. */ lsmblob_init(&lb, scm->secid); - err = security_secid_to_secctx(&lb, &context); + err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY);

if (!err) { put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len, diff --git a/include/net/xfrm.h b/include/net/xfrm.h index cbff7c2a9724..a10fa01f7bf4 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -660,13 +660,22 @@ struct xfrm_spi_skb_cb { #define XFRM_SPI_SKB_CB(__skb) ((struct xfrm_spi_skb_cb *)&((__skb)->cb[0])) #ifdef CONFIG_AUDITSYSCALL -static inline struct audit_buffer *xfrm_audit_start(const char *op) +static inline struct audit_buffer *xfrm_audit_start(const char *op, + struct audit_context **lac) { + struct audit_context *context; struct audit_buffer *audit_buf = NULL; if (audit_enabled == AUDIT_OFF) return NULL; - audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, + context = audit_context(); + if (lac != NULL) { + if (lsm_multiple_contexts() && context == NULL) + context = audit_alloc_local(GFP_ATOMIC); + *lac = context; + } + + audit_buf = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_IPSEC_EVENT); if (audit_buf == NULL) return NULL;

diff --git a/kernel/audit.c b/kernel/audit.c index 841123390d41..cba63789a164 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -386,10 +386,12 @@ void audit_log_lost(const char *message) static int audit_log_config_change(char *function_name, u32 new, u32 old, int allow_changes) { + struct audit_context *context; struct audit_buffer *ab; int rc = 0; - ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE); + context = audit_alloc_for_lsm(GFP_KERNEL); + ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);

@@ -399,6 +401,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old, allow_changes = 0; /* Something weird, deny request */ audit_log_format(ab, " res=%d", allow_changes); audit_log_end(ab); + audit_free_local(context);

@@ -2128,6 +2136,36 @@ void audit_log_key(struct audit_buffer *ab, char *key) audit_log_format(ab, "(null)"); } +static void audit_log_lsm(struct audit_context *context, struct lsmblob *blob)

+{ + struct audit_buffer *ab; + struct lsmcontext lsmdata; + bool sep = false; + int error; + int i; + + ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS); + if (!ab) + return; /* audit_panic or being filtered */ + + for (i = 0; i < LSMBLOB_ENTRIES; i++) { + if (blob->secid[i] == 0) + continue; + error = security_secid_to_secctx(blob, &lsmdata, i); + if (error && error != -EINVAL) { + audit_panic("error in audit_log_lsm"); + return; + } + + audit_log_format(ab, "%ssubj_%s=\"%s\"", sep ? " " : "", + lsm_slot_to_name(i), lsmdata.context); + sep = true;

+ security_release_secctx(&lsmdata); + } + audit_log_end(ab); +}

@@ -2138,7 +2176,18 @@ int audit_log_task_context(struct audit_buffer *ab) if (!lsmblob_is_set(&blob)) return 0; - error = security_secid_to_secctx(&blob, &context); + /* + * If there is more than one security module that has a + * subject "context" it's necessary to put the subject data + * into a separate record to maintain compatibility. + */ + if (lsm_multiple_contexts()) { + audit_log_format(ab, " subj=?"); + audit_log_lsm(ab->ctx, &blob); + return 0; + } + + error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST);

diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 0e58a3ab56f5..01fdcbf468c0 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -993,12 +993,11 @@ struct audit_context *audit_alloc_local(gfp_t gfpflags) context = audit_alloc_context(AUDIT_STATE_BUILD, gfpflags); if (!context) { audit_log_lost("out of memory in audit_alloc_local"); - goto out; + return NULL; } context->serial = audit_serial(); ktime_get_coarse_real_ts64(&context->ctime); context->local = true; -out: return context; }

@@ -1019,6 +1018,13 @@ void audit_free_context(struct audit_context *context) } EXPORT_SYMBOL(audit_free_context); +void audit_free_local(struct audit_context *context) +{ + if (context && context->local) + audit_free_context(context); +} +EXPORT_SYMBOL(audit_free_local);

@@ -1036,7 +1042,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, from_kuid(&init_user_ns, auid), from_kuid(&init_user_ns, uid), sessionid); if (lsmblob_is_set(blob)) { - if (security_secid_to_secctx(blob, &lsmctx)) { + if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) {

diff --git a/security/security.c b/security/security.c index cb359e185d1a..5d7fd982f84a 100644 --- a/security/security.c +++ b/security/security.c @@ -2309,7 +2309,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value, hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) { rc = hp->hook.setprocattr(name, value, size); - if (rc < 0) + if (rc < 0 && rc != -EINVAL) return rc; }