[PATCH v34 13/29] LSM: Use lsmblob in security_cred_getsecid
From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2022-04-07 21:29:29
Also in:
linux-integrity, lkml, selinux
Subsystem:
android drivers, audit subsystem, extended verification module (evm), integrity measurement architecture (ima), security subsystem, the rest · Maintainers:
Greg Kroah-Hartman, Arve Hjønnevåg, Todd Kjos, Christian Brauner, Carlos Llamas, Alice Ryhl, Paul Moore, Eric Paris, Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, James Morris, "Serge E. Hallyn", Linus Torvalds
Possibly related (same subject, not in this thread)
- 2022-04-15 · [PATCH v34 13/29] LSM: Use lsmblob in security_cred_getsecid · Casey Schaufler <casey@schaufler-ca.com>
Change the security_cred_getsecid() interface to fill in a lsmblob instead of a u32 secid. The associated data elements in the audit sub-system are changed from a secid to a lsmblob to accommodate multiple possible LSM audit users. Reviewed-by: Kees Cook <redacted> Reviewed-by: John Johansen <john.johansen@canonical.com> Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Cc: linux-integrity@vger.kernel.org Cc: linux-audit@redhat.com --- drivers/android/binder.c | 12 +---------- include/linux/security.h | 2 +- kernel/audit.c | 25 +++++++---------------- kernel/audit.h | 3 ++- kernel/auditsc.c | 33 +++++++++++-------------------- security/integrity/ima/ima_main.c | 8 ++++---- security/security.c | 12 ++++++++--- 7 files changed, 36 insertions(+), 59 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index bae8440ffc73..26838061defb 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c@@ -2982,18 +2982,8 @@ static void binder_transaction(struct binder_proc *proc, if (target_node && target_node->txn_security_ctx) { struct lsmblob blob; size_t added_size; - u32 secid; - security_cred_getsecid(proc->cred, &secid); - /* - * Later in this patch set security_cred_getsecid() will - * provide a lsmblob instead of a secid. lsmblob_init - * is used to ensure that all the secids in the lsmblob - * get the value returned from security_cred_getsecid(), - * which means that the one expected by - * security_secid_to_secctx() will be set. - */ - lsmblob_init(&blob, secid); + security_cred_getsecid(proc->cred, &blob); ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz); if (ret) { return_error = BR_FAILED_REPLY;
diff --git a/include/linux/security.h b/include/linux/security.h
index 44c92e1aedf2..e36d7f35b228 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h@@ -483,7 +483,7 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t gfp); void security_cred_free(struct cred *cred); int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp); void security_transfer_creds(struct cred *new, const struct cred *old); -void security_cred_getsecid(const struct cred *c, u32 *secid); +void security_cred_getsecid(const struct cred *c, struct lsmblob *blob); int security_kernel_act_as(struct cred *new, struct lsmblob *blob); int security_kernel_create_files_as(struct cred *new, struct inode *inode); int security_kernel_module_request(char *kmod_name);
diff --git a/kernel/audit.c b/kernel/audit.c
index 0a7869c9c9ad..2b670ac129be 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c@@ -125,7 +125,7 @@ static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME; /* The identity of the user shutting down the audit system. */ static kuid_t audit_sig_uid = INVALID_UID; static pid_t audit_sig_pid = -1; -static u32 audit_sig_sid; +struct lsmblob audit_sig_lsm; /* Records can be lost in several ways: 0) [suppressed in audit_alloc]
@@ -1463,29 +1463,21 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) } case AUDIT_SIGNAL_INFO: len = 0; - if (audit_sig_sid) { - struct lsmblob blob; - - /* - * lsmblob_init sets all values in the lsmblob - * to audit_sig_sid. This is temporary until - * audit_sig_sid is converted to a lsmblob, which - * happens later in this patch set. - */ - lsmblob_init(&blob, audit_sig_sid); - err = security_secid_to_secctx(&blob, &ctx, &len); + if (lsmblob_is_set(&audit_sig_lsm)) { + err = security_secid_to_secctx(&audit_sig_lsm, &ctx, + &len); if (err) return err; } sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL); if (!sig_data) { - if (audit_sig_sid) + if (lsmblob_is_set(&audit_sig_lsm)) security_release_secctx(ctx, len); return -ENOMEM; } sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid); sig_data->pid = audit_sig_pid; - if (audit_sig_sid) { + if (lsmblob_is_set(&audit_sig_lsm)) { memcpy(sig_data->ctx, ctx, len); security_release_secctx(ctx, len); }
@@ -2392,7 +2384,6 @@ int audit_set_loginuid(kuid_t loginuid) int audit_signal_info(int sig, struct task_struct *t) { kuid_t uid = current_uid(), auid; - struct lsmblob blob; if (auditd_test_task(t) && (sig == SIGTERM || sig == SIGHUP ||
@@ -2403,9 +2394,7 @@ int audit_signal_info(int sig, struct task_struct *t) audit_sig_uid = auid; else audit_sig_uid = uid; - security_current_getsecid_subj(&blob); - /* scaffolding until audit_sig_sid is converted */ - audit_sig_sid = blob.secid[0]; + security_current_getsecid_subj(&audit_sig_lsm); } return audit_signal_info_syscall(t);
diff --git a/kernel/audit.h b/kernel/audit.h
index 58b66543b4d5..316fac62d5f7 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h@@ -12,6 +12,7 @@ #include <linux/fs.h> #include <linux/audit.h> #include <linux/skbuff.h> +#include <linux/security.h> #include <uapi/linux/mqueue.h> #include <linux/tty.h> #include <uapi/linux/openat2.h> // struct open_how
@@ -143,7 +144,7 @@ struct audit_context { kuid_t target_auid; kuid_t target_uid; unsigned int target_sessionid; - u32 target_sid; + struct lsmblob target_lsm; char target_comm[TASK_COMM_LEN]; struct audit_tree_refs *trees, *first_trees;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index fbc0895a1a93..2b27ef99f0f6 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c@@ -99,7 +99,7 @@ struct audit_aux_data_pids { kuid_t target_auid[AUDIT_AUX_PIDS]; kuid_t target_uid[AUDIT_AUX_PIDS]; unsigned int target_sessionid[AUDIT_AUX_PIDS]; - u32 target_sid[AUDIT_AUX_PIDS]; + struct lsmblob target_lsm[AUDIT_AUX_PIDS]; char target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN]; int pid_count; };
@@ -1018,7 +1018,7 @@ static void audit_reset_context(struct audit_context *ctx) ctx->target_pid = 0; ctx->target_auid = ctx->target_uid = KUIDT_INIT(0); ctx->target_sessionid = 0; - ctx->target_sid = 0; + lsmblob_init(&ctx->target_lsm, 0); ctx->target_comm[0] = '\0'; unroll_tree_refs(ctx, NULL, 0); WARN_ON(!list_empty(&ctx->killed_trees));
@@ -1116,14 +1116,14 @@ static inline void audit_free_context(struct audit_context *context) } static int audit_log_pid_context(struct audit_context *context, pid_t pid, - kuid_t auid, kuid_t uid, unsigned int sessionid, - u32 sid, char *comm) + kuid_t auid, kuid_t uid, + unsigned int sessionid, + struct lsmblob *blob, char *comm) { struct audit_buffer *ab; char *ctx = NULL; u32 len; int rc = 0; - struct lsmblob blob; ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID); if (!ab)
@@ -1132,9 +1132,8 @@ 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 (sid) { - lsmblob_init(&blob, sid); - if (security_secid_to_secctx(&blob, &ctx, &len)) { + if (lsmblob_is_set(blob)) { + if (security_secid_to_secctx(blob, &ctx, &len)) { audit_log_format(ab, " obj=(none)"); rc = 1; } else {
@@ -1814,7 +1813,7 @@ static void audit_log_exit(void) axs->target_auid[i], axs->target_uid[i], axs->target_sessionid[i], - axs->target_sid[i], + &axs->target_lsm[i], axs->target_comm[i])) call_panic = 1; }
@@ -1823,7 +1822,7 @@ static void audit_log_exit(void) audit_log_pid_context(context, context->target_pid, context->target_auid, context->target_uid, context->target_sessionid, - context->target_sid, context->target_comm)) + &context->target_lsm, context->target_comm)) call_panic = 1; if (context->pwd.dentry && context->pwd.mnt) {
@@ -2759,15 +2758,12 @@ int __audit_sockaddr(int len, void *a) void __audit_ptrace(struct task_struct *t) { struct audit_context *context = audit_context(); - struct lsmblob blob; context->target_pid = task_tgid_nr(t); context->target_auid = audit_get_loginuid(t); context->target_uid = task_uid(t); context->target_sessionid = audit_get_sessionid(t); - security_task_getsecid_obj(t, &blob); - /* scaffolding - until target_sid is converted */ - context->target_sid = blob.secid[0]; + security_task_getsecid_obj(t, &context->target_lsm); memcpy(context->target_comm, t->comm, TASK_COMM_LEN); }
@@ -2783,7 +2779,6 @@ int audit_signal_info_syscall(struct task_struct *t) struct audit_aux_data_pids *axp; struct audit_context *ctx = audit_context(); kuid_t t_uid = task_uid(t); - struct lsmblob blob; if (!audit_signals || audit_dummy_context()) return 0;
@@ -2795,9 +2790,7 @@ int audit_signal_info_syscall(struct task_struct *t) ctx->target_auid = audit_get_loginuid(t); ctx->target_uid = t_uid; ctx->target_sessionid = audit_get_sessionid(t); - security_task_getsecid_obj(t, &blob); - /* scaffolding until target_sid is converted */ - ctx->target_sid = blob.secid[0]; + security_task_getsecid_obj(t, &ctx->target_lsm); memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN); return 0; }
@@ -2818,9 +2811,7 @@ int audit_signal_info_syscall(struct task_struct *t) axp->target_auid[axp->pid_count] = audit_get_loginuid(t); axp->target_uid[axp->pid_count] = t_uid; axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t); - security_task_getsecid_obj(t, &blob); - /* scaffolding until target_sid is converted */ - axp->target_sid[axp->pid_count] = blob.secid[0]; + security_task_getsecid_obj(t, &axp->target_lsm[axp->pid_count]); memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN); axp->pid_count++;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 2d99cb996d5f..33cf3432a796 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c@@ -487,7 +487,6 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot) int ima_bprm_check(struct linux_binprm *bprm) { int ret; - u32 secid; struct lsmblob blob; security_current_getsecid_subj(&blob);
@@ -497,9 +496,10 @@ int ima_bprm_check(struct linux_binprm *bprm) if (ret) return ret; - security_cred_getsecid(bprm->cred, &secid); - return process_measurement(bprm->file, bprm->cred, secid, NULL, 0, - MAY_EXEC, CREDS_CHECK); + security_cred_getsecid(bprm->cred, &blob); + /* scaffolding until process_measurement changes */ + return process_measurement(bprm->file, bprm->cred, blob.secid[0], + NULL, 0, MAY_EXEC, CREDS_CHECK); } /**
diff --git a/security/security.c b/security/security.c
index 297a6be2e23a..2ad0d4eb24b3 100644
--- a/security/security.c
+++ b/security/security.c@@ -1816,10 +1816,16 @@ void security_transfer_creds(struct cred *new, const struct cred *old) call_void_hook(cred_transfer, new, old); } -void security_cred_getsecid(const struct cred *c, u32 *secid) +void security_cred_getsecid(const struct cred *c, struct lsmblob *blob) { - *secid = 0; - call_void_hook(cred_getsecid, c, secid); + struct security_hook_list *hp; + + lsmblob_init(blob, 0); + hlist_for_each_entry(hp, &security_hook_heads.cred_getsecid, list) { + if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot)) + continue; + hp->hook.cred_getsecid(c, &blob->secid[hp->lsmid->slot]); + } } EXPORT_SYMBOL(security_cred_getsecid);
--
2.35.1