On 2/19/21 3:29 PM, Paul Moore wrote: > Of the three LSMs that implement the security_task_getsecid() LSM > hook, all three LSMs provide the task's objective security > credentials. This turns out to be unfortunate as most of the hook's > callers seem to expect the task's subjective credentials, although > a small handful of callers do correctly expect the objective > credentials. > > This patch is the first step towards fixing the problem: it splits > the existing security_task_getsecid() hook into two variants, one > for the subjective creds, one for the objective creds. > > void security_task_getsecid_subj(struct task_struct *p, > u32 *secid); > void security_task_getsecid_obj(struct task_struct *p, > u32 *secid); > > While this patch does fix all of the callers to use the correct > variant, in order to keep this patch focused on the callers and to > ease review, the LSMs continue to use the same implementation for > both hooks. The net effect is that this patch should not change > the behavior of the kernel in any way, it will be up to the latter > LSM specific patches in this series to change the hook > implementations and return the correct credentials. > > Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx> So far this looks good. I want to take another stab at it and give it some testing > --- > drivers/android/binder.c | 2 +- > include/linux/cred.h | 2 +- > include/linux/lsm_hook_defs.h | 5 ++++- > include/linux/lsm_hooks.h | 8 ++++++-- > include/linux/security.h | 10 ++++++++-- > kernel/audit.c | 4 ++-- > kernel/auditfilter.c | 3 ++- > kernel/auditsc.c | 8 ++++---- > net/netlabel/netlabel_unlabeled.c | 2 +- > net/netlabel/netlabel_user.h | 2 +- > security/apparmor/lsm.c | 3 ++- > security/integrity/ima/ima_appraise.c | 2 +- > security/integrity/ima/ima_main.c | 14 +++++++------- > security/security.c | 13 ++++++++++--- > security/selinux/hooks.c | 3 ++- > security/smack/smack_lsm.c | 3 ++- > 16 files changed, 54 insertions(+), 30 deletions(-) > > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > index c119736ca56ac..39d501261108d 100644 > --- a/drivers/android/binder.c > +++ b/drivers/android/binder.c > @@ -2700,7 +2700,7 @@ static void binder_transaction(struct binder_proc *proc, > u32 secid; > size_t added_size; > > - security_task_getsecid(proc->tsk, &secid); > + security_task_getsecid_subj(proc->tsk, &secid); > ret = security_secid_to_secctx(secid, &secctx, &secctx_sz); > if (ret) { > return_error = BR_FAILED_REPLY; > diff --git a/include/linux/cred.h b/include/linux/cred.h > index 18639c069263f..42b9d88d9a565 100644 > --- a/include/linux/cred.h > +++ b/include/linux/cred.h > @@ -140,7 +140,7 @@ struct cred { > struct key *request_key_auth; /* assumed request_key authority */ > #endif > #ifdef CONFIG_SECURITY > - void *security; /* subjective LSM security */ > + void *security; /* LSM security */ > #endif > struct user_struct *user; /* real user ID subscription */ > struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */ > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index dfd261dcbcb04..1490a185135a0 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -200,7 +200,10 @@ LSM_HOOK(int, 0, task_fix_setgid, struct cred *new, const struct cred * old, > LSM_HOOK(int, 0, task_setpgid, struct task_struct *p, pid_t pgid) > LSM_HOOK(int, 0, task_getpgid, struct task_struct *p) > LSM_HOOK(int, 0, task_getsid, struct task_struct *p) > -LSM_HOOK(void, LSM_RET_VOID, task_getsecid, struct task_struct *p, u32 *secid) > +LSM_HOOK(void, LSM_RET_VOID, task_getsecid_subj, > + struct task_struct *p, u32 *secid) > +LSM_HOOK(void, LSM_RET_VOID, task_getsecid_obj, > + struct task_struct *p, u32 *secid) > LSM_HOOK(int, 0, task_setnice, struct task_struct *p, int nice) > LSM_HOOK(int, 0, task_setioprio, struct task_struct *p, int ioprio) > LSM_HOOK(int, 0, task_getioprio, struct task_struct *p) > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index bdfc8a76a4f79..13d2a9a6f2014 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -706,8 +706,12 @@ > * @p. > * @p contains the task_struct for the process. > * Return 0 if permission is granted. > - * @task_getsecid: > - * Retrieve the security identifier of the process @p. > + * @task_getsecid_subj: > + * Retrieve the subjective security identifier of the process @p. > + * @p contains the task_struct for the process and place is into @secid. > + * In case of failure, @secid will be set to zero. > + * @task_getsecid_obj: > + * Retrieve the objective security identifier of the process @p. > * @p contains the task_struct for the process and place is into @secid. > * In case of failure, @secid will be set to zero. > * > diff --git a/include/linux/security.h b/include/linux/security.h > index b0d14f04b16de..1826bb0cea825 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -406,7 +406,8 @@ int security_task_fix_setgid(struct cred *new, const struct cred *old, > int security_task_setpgid(struct task_struct *p, pid_t pgid); > int security_task_getpgid(struct task_struct *p); > int security_task_getsid(struct task_struct *p); > -void security_task_getsecid(struct task_struct *p, u32 *secid); > +void security_task_getsecid_subj(struct task_struct *p, u32 *secid); > +void security_task_getsecid_obj(struct task_struct *p, u32 *secid); > int security_task_setnice(struct task_struct *p, int nice); > int security_task_setioprio(struct task_struct *p, int ioprio); > int security_task_getioprio(struct task_struct *p); > @@ -1084,7 +1085,12 @@ static inline int security_task_getsid(struct task_struct *p) > return 0; > } > > -static inline void security_task_getsecid(struct task_struct *p, u32 *secid) > +static inline void security_task_getsecid_subj(struct task_struct *p, u32 *secid) > +{ > + *secid = 0; > +} > + > +static inline void security_task_getsecid_obj(struct task_struct *p, u32 *secid) > { > *secid = 0; > } > diff --git a/kernel/audit.c b/kernel/audit.c > index 1ffc2e059027d..8e725db6ecb02 100644 > --- a/kernel/audit.c > +++ b/kernel/audit.c > @@ -2132,7 +2132,7 @@ int audit_log_task_context(struct audit_buffer *ab) > int error; > u32 sid; > > - security_task_getsecid(current, &sid); > + security_task_getsecid_subj(current, &sid); > if (!sid) > return 0; > > @@ -2353,7 +2353,7 @@ int audit_signal_info(int sig, struct task_struct *t) > audit_sig_uid = auid; > else > audit_sig_uid = uid; > - security_task_getsecid(current, &audit_sig_sid); > + security_task_getsecid_subj(current, &audit_sig_sid); > } > > return audit_signal_info_syscall(t); > diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c > index 333b3bcfc5458..db2c6b59dfc33 100644 > --- a/kernel/auditfilter.c > +++ b/kernel/auditfilter.c > @@ -1359,7 +1359,8 @@ int audit_filter(int msgtype, unsigned int listtype) > case AUDIT_SUBJ_SEN: > case AUDIT_SUBJ_CLR: > if (f->lsm_rule) { > - security_task_getsecid(current, &sid); > + security_task_getsecid_subj(current, > + &sid); > result = security_audit_rule_match(sid, > f->type, f->op, f->lsm_rule); > } > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index ce8c9e2279ba9..3bfbecca4664a 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -667,7 +667,7 @@ static int audit_filter_rules(struct task_struct *tsk, > logged upon error */ > if (f->lsm_rule) { > if (need_sid) { > - security_task_getsecid(tsk, &sid); > + security_task_getsecid_subj(tsk, &sid); > need_sid = 0; > } > result = security_audit_rule_match(sid, f->type, > @@ -2400,7 +2400,7 @@ void __audit_ptrace(struct task_struct *t) > context->target_auid = audit_get_loginuid(t); > context->target_uid = task_uid(t); > context->target_sessionid = audit_get_sessionid(t); > - security_task_getsecid(t, &context->target_sid); > + security_task_getsecid_obj(t, &context->target_sid); > memcpy(context->target_comm, t->comm, TASK_COMM_LEN); > } > > @@ -2427,7 +2427,7 @@ 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(t, &ctx->target_sid); > + security_task_getsecid_obj(t, &ctx->target_sid); > memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN); > return 0; > } > @@ -2448,7 +2448,7 @@ 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(t, &axp->target_sid[axp->pid_count]); > + security_task_getsecid_obj(t, &axp->target_sid[axp->pid_count]); > memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN); > axp->pid_count++; > > diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c > index ccb4916428116..3e6ac9b790b15 100644 > --- a/net/netlabel/netlabel_unlabeled.c > +++ b/net/netlabel/netlabel_unlabeled.c > @@ -1539,7 +1539,7 @@ int __init netlbl_unlabel_defconf(void) > /* Only the kernel is allowed to call this function and the only time > * it is called is at bootup before the audit subsystem is reporting > * messages so don't worry to much about these values. */ > - security_task_getsecid(current, &audit_info.secid); > + security_task_getsecid_subj(current, &audit_info.secid); > audit_info.loginuid = GLOBAL_ROOT_UID; > audit_info.sessionid = 0; > > diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h > index 3c67afce64f12..b9ba8112b3c52 100644 > --- a/net/netlabel/netlabel_user.h > +++ b/net/netlabel/netlabel_user.h > @@ -34,7 +34,7 @@ > static inline void netlbl_netlink_auditinfo(struct sk_buff *skb, > struct netlbl_audit *audit_info) > { > - security_task_getsecid(current, &audit_info->secid); > + security_task_getsecid_subj(current, &audit_info->secid); > audit_info->loginuid = audit_get_loginuid(current); > audit_info->sessionid = audit_get_sessionid(current); > } > diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c > index 1b0aba8eb7235..15e37b9132679 100644 > --- a/security/apparmor/lsm.c > +++ b/security/apparmor/lsm.c > @@ -1243,7 +1243,8 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = { > > LSM_HOOK_INIT(task_free, apparmor_task_free), > LSM_HOOK_INIT(task_alloc, apparmor_task_alloc), > - LSM_HOOK_INIT(task_getsecid, apparmor_task_getsecid), > + LSM_HOOK_INIT(task_getsecid_subj, apparmor_task_getsecid), > + LSM_HOOK_INIT(task_getsecid_obj, apparmor_task_getsecid), > LSM_HOOK_INIT(task_setrlimit, apparmor_task_setrlimit), > LSM_HOOK_INIT(task_kill, apparmor_task_kill), > > diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c > index 8361941ee0a12..afa4923dbd33d 100644 > --- a/security/integrity/ima/ima_appraise.c > +++ b/security/integrity/ima/ima_appraise.c > @@ -75,7 +75,7 @@ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func) > if (!ima_appraise) > return 0; > > - security_task_getsecid(current, &secid); > + security_task_getsecid_subj(current, &secid); > return ima_match_policy(inode, current_cred(), secid, func, mask, > IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL); > } > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > index f87cb29329e91..97a6913bb3d86 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -391,7 +391,7 @@ int ima_file_mmap(struct file *file, unsigned long prot) > u32 secid; > > if (file && (prot & PROT_EXEC)) { > - security_task_getsecid(current, &secid); > + security_task_getsecid_subj(current, &secid); > return process_measurement(file, current_cred(), secid, NULL, > 0, MAY_EXEC, MMAP_CHECK); > } > @@ -429,7 +429,7 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot) > !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC)) > return 0; > > - security_task_getsecid(current, &secid); > + security_task_getsecid_subj(current, &secid); > inode = file_inode(vma->vm_file); > action = ima_get_action(inode, current_cred(), secid, MAY_EXEC, > MMAP_CHECK, &pcr, &template, 0); > @@ -469,7 +469,7 @@ int ima_bprm_check(struct linux_binprm *bprm) > int ret; > u32 secid; > > - security_task_getsecid(current, &secid); > + security_task_getsecid_subj(current, &secid); > ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0, > MAY_EXEC, BPRM_CHECK); > if (ret) > @@ -494,7 +494,7 @@ int ima_file_check(struct file *file, int mask) > { > u32 secid; > > - security_task_getsecid(current, &secid); > + security_task_getsecid_subj(current, &secid); > return process_measurement(file, current_cred(), secid, NULL, 0, > mask & (MAY_READ | MAY_WRITE | MAY_EXEC | > MAY_APPEND), FILE_CHECK); > @@ -679,7 +679,7 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id, > > /* Read entire file for all partial reads. */ > func = read_idmap[read_id] ?: FILE_CHECK; > - security_task_getsecid(current, &secid); > + security_task_getsecid_subj(current, &secid); > return process_measurement(file, current_cred(), secid, NULL, > 0, MAY_READ, func); > } > @@ -722,7 +722,7 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, > } > > func = read_idmap[read_id] ?: FILE_CHECK; > - security_task_getsecid(current, &secid); > + security_task_getsecid_subj(current, &secid); > return process_measurement(file, current_cred(), secid, buf, size, > MAY_READ, func); > } > @@ -859,7 +859,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, > * buffer measurements. > */ > if (func) { > - security_task_getsecid(current, &secid); > + security_task_getsecid_subj(current, &secid); > action = ima_get_action(inode, current_cred(), secid, 0, func, > &pcr, &template, keyring); > if (!(action & IMA_MEASURE)) > diff --git a/security/security.c b/security/security.c > index 401663b5b70ea..85e504df051b3 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -1757,12 +1757,19 @@ int security_task_getsid(struct task_struct *p) > return call_int_hook(task_getsid, 0, p); > } > > -void security_task_getsecid(struct task_struct *p, u32 *secid) > +void security_task_getsecid_subj(struct task_struct *p, u32 *secid) > { > *secid = 0; > - call_void_hook(task_getsecid, p, secid); > + call_void_hook(task_getsecid_subj, p, secid); > } > -EXPORT_SYMBOL(security_task_getsecid); > +EXPORT_SYMBOL(security_task_getsecid_subj); > + > +void security_task_getsecid_obj(struct task_struct *p, u32 *secid) > +{ > + *secid = 0; > + call_void_hook(task_getsecid_obj, p, secid); > +} > +EXPORT_SYMBOL(security_task_getsecid_obj); > > int security_task_setnice(struct task_struct *p, int nice) > { > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index af2994adf9dd1..f311541c4972e 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -7143,7 +7143,8 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { > LSM_HOOK_INIT(task_setpgid, selinux_task_setpgid), > LSM_HOOK_INIT(task_getpgid, selinux_task_getpgid), > LSM_HOOK_INIT(task_getsid, selinux_task_getsid), > - LSM_HOOK_INIT(task_getsecid, selinux_task_getsecid), > + LSM_HOOK_INIT(task_getsecid_subj, selinux_task_getsecid), > + LSM_HOOK_INIT(task_getsecid_obj, selinux_task_getsecid), > LSM_HOOK_INIT(task_setnice, selinux_task_setnice), > LSM_HOOK_INIT(task_setioprio, selinux_task_setioprio), > LSM_HOOK_INIT(task_getioprio, selinux_task_getioprio), > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index f69c3dd9a0c67..2bb354ef2c4a9 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -4755,7 +4755,8 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { > LSM_HOOK_INIT(task_setpgid, smack_task_setpgid), > LSM_HOOK_INIT(task_getpgid, smack_task_getpgid), > LSM_HOOK_INIT(task_getsid, smack_task_getsid), > - LSM_HOOK_INIT(task_getsecid, smack_task_getsecid), > + LSM_HOOK_INIT(task_getsecid_subj, smack_task_getsecid), > + LSM_HOOK_INIT(task_getsecid_obj, smack_task_getsecid), > LSM_HOOK_INIT(task_setnice, smack_task_setnice), > LSM_HOOK_INIT(task_setioprio, smack_task_setioprio), > LSM_HOOK_INIT(task_getioprio, smack_task_getioprio), >