On Fri Aug 2, 2024 at 4:10 PM EEST, Jann Horn wrote: > cred_alloc_blank and cred_transfer were only necessary so that keyctl can > allocate creds in the child and then asynchronously have the parent fill > them in and apply them. > > Get rid of them by letting the child synchronously wait for the task work > executing in the parent's context. This way, any errors that happen in the > task work can be plumbed back into the syscall return value in the child. > > Note that this requires using TWA_SIGNAL instead of TWA_RESUME, so the > parent might observe some spurious -EGAIN syscall returns or such; but the > parent likely anyway has to be ready to deal with the side effects of > receiving signals (since it'll probably get SIGCHLD when the child dies), > so that probably isn't an issue. > > Signed-off-by: Jann Horn <jannh@xxxxxxxxxx> > --- > This is a quickly hacked up demo of the approach I proposed at > <https://lore.kernel.org/all/CAG48ez2bnvuX8i-D=5DxmfzEOKTWAf-DkgQq6aNC4WzSGoEGHg@xxxxxxxxxxxxxx/> > to get rid of the cred_transfer stuff. Diffstat looks like this: > > include/linux/cred.h | 1 - > include/linux/lsm_hook_defs.h | 3 --- > include/linux/security.h | 12 ------------ > kernel/cred.c | 23 ----------------------- > security/apparmor/lsm.c | 19 ------------------- > security/keys/internal.h | 8 ++++++++ > security/keys/keyctl.c | 100 ++++++++++++++++++++++++++-------------------------------------------------------------------------- > security/keys/process_keys.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++---------------------------------------- > security/landlock/cred.c | 11 ++--------- > security/security.c | 35 ----------------------------------- > security/selinux/hooks.c | 12 ------------ > security/smack/smack_lsm.c | 32 -------------------------------- > 12 files changed, 82 insertions(+), 260 deletions(-) > > What do you think? Synchronously waiting for task work is a bit ugly, > but at least this condenses the uglyness in the keys subsystem instead > of making the rest of the security subsystem deal with this stuff. Why does synchronously waiting is ugly? Not sarcasm, I genuineily interested of breaking that down in smaller pieces. E.g. what disadvantages would be there from your point of view? Only trying to form a common picture, that's all. > > Another approach to simplify things further would be to try to move > the session keyring out of the creds entirely and just let the child > update it directly with appropriate locking, but I don't know enough > about the keys subsystem to know if that would maybe break stuff > that relies on override_creds() also overriding the keyrings, or > something like that. > --- > include/linux/cred.h | 1 - > include/linux/lsm_hook_defs.h | 3 -- > include/linux/security.h | 12 ----- > kernel/cred.c | 23 ---------- > security/apparmor/lsm.c | 19 -------- > security/keys/internal.h | 8 ++++ > security/keys/keyctl.c | 100 +++++++++++------------------------------- > security/keys/process_keys.c | 86 +++++++++++++++++++----------------- > security/landlock/cred.c | 11 +---- > security/security.c | 35 --------------- > security/selinux/hooks.c | 12 ----- > security/smack/smack_lsm.c | 32 -------------- > 12 files changed, 82 insertions(+), 260 deletions(-) Given the large patch size: 1. If it is impossible to split some meaningful patches, i.e. patches that transform kernel tree from working state to another, I can cope with this. 2. Even for small chunks that can be split into their own logical pieces: please do that. Helps to review the main gist later on. > > diff --git a/include/linux/cred.h b/include/linux/cred.h > index 2976f534a7a3..54b5105d4cd5 100644 > --- a/include/linux/cred.h > +++ b/include/linux/cred.h > @@ -147,13 +147,12 @@ struct cred { > } __randomize_layout; > > extern void __put_cred(struct cred *); > extern void exit_creds(struct task_struct *); > extern int copy_creds(struct task_struct *, unsigned long); > extern const struct cred *get_task_cred(struct task_struct *); > -extern struct cred *cred_alloc_blank(void); > extern struct cred *prepare_creds(void); > extern struct cred *prepare_exec_creds(void); > extern int commit_creds(struct cred *); > extern void abort_creds(struct cred *); > extern const struct cred *override_creds(const struct cred *); > extern void revert_creds(const struct cred *); > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index 855db460e08b..1d75075cb607 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -204,18 +204,15 @@ LSM_HOOK(int, 0, file_receive, struct file *file) > LSM_HOOK(int, 0, file_open, struct file *file) > LSM_HOOK(int, 0, file_post_open, struct file *file, int mask) > LSM_HOOK(int, 0, file_truncate, struct file *file) > LSM_HOOK(int, 0, task_alloc, struct task_struct *task, > unsigned long clone_flags) > LSM_HOOK(void, LSM_RET_VOID, task_free, struct task_struct *task) > -LSM_HOOK(int, 0, cred_alloc_blank, struct cred *cred, gfp_t gfp) > LSM_HOOK(void, LSM_RET_VOID, cred_free, struct cred *cred) > LSM_HOOK(int, 0, cred_prepare, struct cred *new, const struct cred *old, > gfp_t gfp) > -LSM_HOOK(void, LSM_RET_VOID, cred_transfer, struct cred *new, > - const struct cred *old) > LSM_HOOK(void, LSM_RET_VOID, cred_getsecid, const struct cred *c, u32 *secid) > LSM_HOOK(int, 0, kernel_act_as, struct cred *new, u32 secid) > LSM_HOOK(int, 0, kernel_create_files_as, struct cred *new, struct inode *inode) > LSM_HOOK(int, 0, kernel_module_request, char *kmod_name) > LSM_HOOK(int, 0, kernel_load_data, enum kernel_load_data_id id, bool contents) > LSM_HOOK(int, 0, kernel_post_load_data, char *buf, loff_t size, > diff --git a/include/linux/security.h b/include/linux/security.h > index 1390f1efb4f0..a366c2a03f55 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -421,16 +421,14 @@ int security_file_send_sigiotask(struct task_struct *tsk, > int security_file_receive(struct file *file); > int security_file_open(struct file *file); > int security_file_post_open(struct file *file, int mask); > int security_file_truncate(struct file *file); > int security_task_alloc(struct task_struct *task, unsigned long clone_flags); > void security_task_free(struct task_struct *task); > -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); > int security_kernel_act_as(struct cred *new, u32 secid); > int security_kernel_create_files_as(struct cred *new, struct inode *inode); > int security_kernel_module_request(char *kmod_name); > int security_kernel_load_data(enum kernel_load_data_id id, bool contents); > int security_kernel_post_load_data(char *buf, loff_t size, > @@ -1117,32 +1115,22 @@ static inline int security_task_alloc(struct task_struct *task, > return 0; > } > > static inline void security_task_free(struct task_struct *task) > { } > > -static inline int security_cred_alloc_blank(struct cred *cred, gfp_t gfp) > -{ > - return 0; > -} > - > static inline void security_cred_free(struct cred *cred) > { } > > static inline int security_prepare_creds(struct cred *new, > const struct cred *old, > gfp_t gfp) > { > return 0; > } > > -static inline void security_transfer_creds(struct cred *new, > - const struct cred *old) > -{ > -} > - > static inline void security_cred_getsecid(const struct cred *c, u32 *secid) > { > *secid = 0; > } > > static inline int security_kernel_act_as(struct cred *cred, u32 secid) > diff --git a/kernel/cred.c b/kernel/cred.c > index 075cfa7c896f..b2f6130cd6b7 100644 > --- a/kernel/cred.c > +++ b/kernel/cred.c > @@ -163,35 +163,12 @@ const struct cred *get_task_cred(struct task_struct *task) > > rcu_read_unlock(); > return cred; > } > EXPORT_SYMBOL(get_task_cred); > > -/* > - * Allocate blank credentials, such that the credentials can be filled in at a > - * later date without risk of ENOMEM. > - */ > -struct cred *cred_alloc_blank(void) > -{ > - struct cred *new; > - > - new = kmem_cache_zalloc(cred_jar, GFP_KERNEL); > - if (!new) > - return NULL; > - > - atomic_long_set(&new->usage, 1); > - if (security_cred_alloc_blank(new, GFP_KERNEL_ACCOUNT) < 0) > - goto error; > - > - return new; > - > -error: > - abort_creds(new); > - return NULL; > -} > - > /** > * prepare_creds - Prepare a new set of credentials for modification > * > * Prepare a new set of task credentials for modification. A task's creds > * shouldn't generally be modified directly, therefore this function is used to > * prepare a new copy, which the caller then modifies and then commits by > diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c > index 808060f9effb..089d53978d9e 100644 > --- a/security/apparmor/lsm.c > +++ b/security/apparmor/lsm.c > @@ -74,39 +74,22 @@ static DEFINE_PER_CPU(struct aa_local_cache, aa_local_buffers); > static void apparmor_cred_free(struct cred *cred) > { > aa_put_label(cred_label(cred)); > set_cred_label(cred, NULL); > } > > -/* > - * allocate the apparmor part of blank credentials > - */ > -static int apparmor_cred_alloc_blank(struct cred *cred, gfp_t gfp) > -{ > - set_cred_label(cred, NULL); > - return 0; > -} > - > /* > * prepare new cred label for modification by prepare_cred block > */ > static int apparmor_cred_prepare(struct cred *new, const struct cred *old, > gfp_t gfp) > { > set_cred_label(new, aa_get_newest_label(cred_label(old))); > return 0; > } > > -/* > - * transfer the apparmor data to a blank set of creds > - */ > -static void apparmor_cred_transfer(struct cred *new, const struct cred *old) > -{ > - set_cred_label(new, aa_get_newest_label(cred_label(old))); > -} > - > static void apparmor_task_free(struct task_struct *task) > { > > aa_free_task_ctx(task_ctx(task)); > } > > @@ -1504,16 +1487,14 @@ static struct security_hook_list apparmor_hooks[] __ro_after_init = { > apparmor_socket_getpeersec_dgram), > LSM_HOOK_INIT(sock_graft, apparmor_sock_graft), > #ifdef CONFIG_NETWORK_SECMARK > LSM_HOOK_INIT(inet_conn_request, apparmor_inet_conn_request), > #endif > > - LSM_HOOK_INIT(cred_alloc_blank, apparmor_cred_alloc_blank), > LSM_HOOK_INIT(cred_free, apparmor_cred_free), > LSM_HOOK_INIT(cred_prepare, apparmor_cred_prepare), > - LSM_HOOK_INIT(cred_transfer, apparmor_cred_transfer), > > LSM_HOOK_INIT(bprm_creds_for_exec, apparmor_bprm_creds_for_exec), > LSM_HOOK_INIT(bprm_committing_creds, apparmor_bprm_committing_creds), > LSM_HOOK_INIT(bprm_committed_creds, apparmor_bprm_committed_creds), > > LSM_HOOK_INIT(task_free, apparmor_task_free), > diff --git a/security/keys/internal.h b/security/keys/internal.h > index 2cffa6dc8255..2c5eadc04cf2 100644 > --- a/security/keys/internal.h > +++ b/security/keys/internal.h > @@ -157,12 +157,20 @@ extern struct key *request_key_and_link(struct key_type *type, > unsigned long flags); > > extern bool lookup_user_key_possessed(const struct key *key, > const struct key_match_data *match_data); > > extern long join_session_keyring(const char *name); > + > +struct keyctl_session_to_parent_context { > + struct callback_head work; > + struct completion done; > + struct key *new_session_keyring; > + const struct cred *child_cred; > + int result; > +}; > extern void key_change_session_keyring(struct callback_head *twork); > > extern struct work_struct key_gc_work; > extern unsigned key_gc_delay; > extern void keyring_gc(struct key *keyring, time64_t limit); > extern void keyring_restriction_gc(struct key *keyring, > diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c > index ab927a142f51..116ef2dfa5a1 100644 > --- a/security/keys/keyctl.c > +++ b/security/keys/keyctl.c > @@ -1616,104 +1616,56 @@ long keyctl_get_security(key_serial_t keyid, > * parent process. > * > * The keyring must exist and must grant the caller LINK permission, and the > * parent process must be single-threaded and must have the same effective > * ownership as this process and mustn't be SUID/SGID. > * > - * The keyring will be emplaced on the parent when it next resumes userspace. > + * The keyring will be emplaced on the parent via a pseudo-signal. > * > * If successful, 0 will be returned. > */ > long keyctl_session_to_parent(void) > { > - struct task_struct *me, *parent; > - const struct cred *mycred, *pcred; > - struct callback_head *newwork, *oldwork; > + struct keyctl_session_to_parent_context ctx; > + struct task_struct *parent; > key_ref_t keyring_r; > - struct cred *cred; > int ret; > > keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK); > if (IS_ERR(keyring_r)) > return PTR_ERR(keyring_r); > > - ret = -ENOMEM; > - > - /* our parent is going to need a new cred struct, a new tgcred struct > - * and new security data, so we allocate them here to prevent ENOMEM in > - * our parent */ > - cred = cred_alloc_blank(); > - if (!cred) > - goto error_keyring; > - newwork = &cred->rcu; > + write_lock_irq(&tasklist_lock); > + parent = get_task_struct(rcu_dereference_protected(current->real_parent, > + lockdep_is_held(&tasklist_lock))); > + write_unlock_irq(&tasklist_lock); > > - cred->session_keyring = key_ref_to_ptr(keyring_r); > - keyring_r = NULL; > - init_task_work(newwork, key_change_session_keyring); > + /* the parent mustn't be init and mustn't be a kernel thread */ > + if (is_global_init(parent) || (READ_ONCE(parent->flags) & PF_KTHREAD) != 0) > + goto put_task; > > - me = current; > - rcu_read_lock(); > - write_lock_irq(&tasklist_lock); > + ctx.new_session_keyring = key_ref_to_ptr(keyring_r); > + ctx.child_cred = current_cred(); > + init_completion(&ctx.done); > + init_task_work(&ctx.work, key_change_session_keyring); > + ret = task_work_add(parent, &ctx.work, TWA_SIGNAL); > + if (ret) > + goto put_task; > > - ret = -EPERM; > - oldwork = NULL; > - parent = rcu_dereference_protected(me->real_parent, > - lockdep_is_held(&tasklist_lock)); > + ret = wait_for_completion_killable(&ctx.done); > > - /* the parent mustn't be init and mustn't be a kernel thread */ > - if (parent->pid <= 1 || !parent->mm) > - goto unlock; > - > - /* the parent must be single threaded */ > - if (!thread_group_empty(parent)) > - goto unlock; > - > - /* the parent and the child must have different session keyrings or > - * there's no point */ > - mycred = current_cred(); > - pcred = __task_cred(parent); > - if (mycred == pcred || > - mycred->session_keyring == pcred->session_keyring) { > - ret = 0; > - goto unlock; > + if (task_work_cancel(parent, &ctx.work)) { > + /* we got killed, task work has been cancelled */ > + } else { > + /* task work is running or has been executed */ > + wait_for_completion(&ctx.done); > + ret = ctx.result; > } > > - /* the parent must have the same effective ownership and mustn't be > - * SUID/SGID */ > - if (!uid_eq(pcred->uid, mycred->euid) || > - !uid_eq(pcred->euid, mycred->euid) || > - !uid_eq(pcred->suid, mycred->euid) || > - !gid_eq(pcred->gid, mycred->egid) || > - !gid_eq(pcred->egid, mycred->egid) || > - !gid_eq(pcred->sgid, mycred->egid)) > - goto unlock; > - > - /* the keyrings must have the same UID */ > - if ((pcred->session_keyring && > - !uid_eq(pcred->session_keyring->uid, mycred->euid)) || > - !uid_eq(mycred->session_keyring->uid, mycred->euid)) > - goto unlock; > - > - /* cancel an already pending keyring replacement */ > - oldwork = task_work_cancel_func(parent, key_change_session_keyring); > - > - /* the replacement session keyring is applied just prior to userspace > - * restarting */ > - ret = task_work_add(parent, newwork, TWA_RESUME); > - if (!ret) > - newwork = NULL; > -unlock: > - write_unlock_irq(&tasklist_lock); > - rcu_read_unlock(); > - if (oldwork) > - put_cred(container_of(oldwork, struct cred, rcu)); > - if (newwork) > - put_cred(cred); > - return ret; > - > -error_keyring: > +put_task: > + put_task_struct(parent); > key_ref_put(keyring_r); > return ret; > } > > /* > * Apply a restriction to a given keyring. > diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c > index b5d5333ab330..199c5dd34792 100644 > --- a/security/keys/process_keys.c > +++ b/security/keys/process_keys.c > @@ -902,59 +902,65 @@ long join_session_keyring(const char *name) > error: > abort_creds(new); > return ret; > } > > /* > - * Replace a process's session keyring on behalf of one of its children when > - * the target process is about to resume userspace execution. > + * Replace a process's session keyring on behalf of one of its children. > + * This function runs in task context, while the child is blocked in > + * keyctl_session_to_parent(). > */ > -void key_change_session_keyring(struct callback_head *twork) > +void key_change_session_keyring(struct callback_head *work) > { > - const struct cred *old = current_cred(); > - struct cred *new = container_of(twork, struct cred, rcu); > + struct keyctl_session_to_parent_context *ctx = > + container_of(work, struct keyctl_session_to_parent_context, work); > + const struct cred *pcred = current_cred(); > + const struct cred *ccred = ctx->child_cred; > + struct cred *new; > > - if (unlikely(current->flags & PF_EXITING)) { > - put_cred(new); > - return; > - } > + /* do checks */ > + ctx->result = -EPERM; > + if (unlikely(current->flags & PF_EXITING)) > + goto out; > > - /* If get_ucounts fails more bits are needed in the refcount */ > - if (unlikely(!get_ucounts(old->ucounts))) { > - WARN_ONCE(1, "In %s get_ucounts failed\n", __func__); > - put_cred(new); > - return; > - } > + /* we must be single threaded */ > + if (!thread_group_empty(current)) > + goto out; > + > + /* > + * the parent must have the same effective ownership and mustn't be > + * SUID/SGID > + */ > + if (!uid_eq(pcred->uid, ccred->euid) || > + !uid_eq(pcred->euid, ccred->euid) || > + !uid_eq(pcred->suid, ccred->euid) || > + !gid_eq(pcred->gid, ccred->egid) || > + !gid_eq(pcred->egid, ccred->egid) || > + !gid_eq(pcred->sgid, ccred->egid)) > + goto out; > + > + /* the keyrings must have the same UID */ > + if ((pcred->session_keyring && > + !uid_eq(pcred->session_keyring->uid, ccred->euid)) || > + !uid_eq(ctx->new_session_keyring->uid, ccred->euid)) > + goto out; > + > + > + /* okay, try to update creds */ > + ctx->result = -ENOMEM; > + new = prepare_creds(); > + if (!new) > + goto out; > > - new-> uid = old-> uid; > - new-> euid = old-> euid; > - new-> suid = old-> suid; > - new->fsuid = old->fsuid; > - new-> gid = old-> gid; > - new-> egid = old-> egid; > - new-> sgid = old-> sgid; > - new->fsgid = old->fsgid; > - new->user = get_uid(old->user); > - new->ucounts = old->ucounts; > - new->user_ns = get_user_ns(old->user_ns); > - new->group_info = get_group_info(old->group_info); > - > - new->securebits = old->securebits; > - new->cap_inheritable = old->cap_inheritable; > - new->cap_permitted = old->cap_permitted; > - new->cap_effective = old->cap_effective; > - new->cap_ambient = old->cap_ambient; > - new->cap_bset = old->cap_bset; > - > - new->jit_keyring = old->jit_keyring; > - new->thread_keyring = key_get(old->thread_keyring); > - new->process_keyring = key_get(old->process_keyring); > - > - security_transfer_creds(new, old); > + key_put(new->session_keyring); > + new->session_keyring = key_get(ctx->new_session_keyring); > > commit_creds(new); > + ctx->result = 0; > +out: > + complete_all(&ctx->done); > } > > /* > * Make sure that root's user and user-session keyrings exist. > */ > static int __init init_root_keyring(void) > diff --git a/security/landlock/cred.c b/security/landlock/cred.c > index db9fe7d906ba..786af18c4a1c 100644 > --- a/security/landlock/cred.c > +++ b/security/landlock/cred.c > @@ -11,41 +11,34 @@ > > #include "common.h" > #include "cred.h" > #include "ruleset.h" > #include "setup.h" > > -static void hook_cred_transfer(struct cred *const new, > - const struct cred *const old) > +static int hook_cred_prepare(struct cred *const new, > + const struct cred *const old, const gfp_t gfp) > { > struct landlock_ruleset *const old_dom = landlock_cred(old)->domain; > > if (old_dom) { > landlock_get_ruleset(old_dom); > landlock_cred(new)->domain = old_dom; > } > -} > - > -static int hook_cred_prepare(struct cred *const new, > - const struct cred *const old, const gfp_t gfp) > -{ > - hook_cred_transfer(new, old); > return 0; > } > > static void hook_cred_free(struct cred *const cred) > { > struct landlock_ruleset *const dom = landlock_cred(cred)->domain; > > if (dom) > landlock_put_ruleset_deferred(dom); > } > > static struct security_hook_list landlock_hooks[] __ro_after_init = { > LSM_HOOK_INIT(cred_prepare, hook_cred_prepare), > - LSM_HOOK_INIT(cred_transfer, hook_cred_transfer), > LSM_HOOK_INIT(cred_free, hook_cred_free), > }; > > __init void landlock_add_cred_hooks(void) > { > security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks), > diff --git a/security/security.c b/security/security.c > index 8cee5b6c6e6d..4fb81de5cf80 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -3057,35 +3057,12 @@ void security_task_free(struct task_struct *task) > call_void_hook(task_free, task); > > kfree(task->security); > task->security = NULL; > } > > -/** > - * security_cred_alloc_blank() - Allocate the min memory to allow cred_transfer > - * @cred: credentials > - * @gfp: gfp flags > - * > - * Only allocate sufficient memory and attach to @cred such that > - * cred_transfer() will not get ENOMEM. > - * > - * Return: Returns 0 on success, negative values on failure. > - */ > -int security_cred_alloc_blank(struct cred *cred, gfp_t gfp) > -{ > - int rc = lsm_cred_alloc(cred, gfp); > - > - if (rc) > - return rc; > - > - rc = call_int_hook(cred_alloc_blank, cred, gfp); > - if (unlikely(rc)) > - security_cred_free(cred); > - return rc; > -} > - > /** > * security_cred_free() - Free the cred's LSM blob and associated resources > * @cred: credentials > * > * Deallocate and clear the cred->security field in a set of credentials. > */ > @@ -3124,24 +3101,12 @@ int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp) > rc = call_int_hook(cred_prepare, new, old, gfp); > if (unlikely(rc)) > security_cred_free(new); > return rc; > } > > -/** > - * security_transfer_creds() - Transfer creds > - * @new: target credentials > - * @old: original credentials > - * > - * Transfer data from original creds to new creds. > - */ > -void security_transfer_creds(struct cred *new, const struct cred *old) > -{ > - call_void_hook(cred_transfer, new, old); > -} > - > /** > * security_cred_getsecid() - Get the secid from a set of credentials > * @c: credentials > * @secid: secid value > * > * Retrieve the security identifier of the cred structure @c. In case of > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 55c78c318ccd..8a659475cc12 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -4007,23 +4007,12 @@ static int selinux_cred_prepare(struct cred *new, const struct cred *old, > struct task_security_struct *tsec = selinux_cred(new); > > *tsec = *old_tsec; > return 0; > } > > -/* > - * transfer the SELinux data to a blank set of creds > - */ > -static void selinux_cred_transfer(struct cred *new, const struct cred *old) > -{ > - const struct task_security_struct *old_tsec = selinux_cred(old); > - struct task_security_struct *tsec = selinux_cred(new); > - > - *tsec = *old_tsec; > -} > - > static void selinux_cred_getsecid(const struct cred *c, u32 *secid) > { > *secid = cred_sid(c); > } > > /* > @@ -7213,13 +7202,12 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = { > LSM_HOOK_INIT(file_receive, selinux_file_receive), > > LSM_HOOK_INIT(file_open, selinux_file_open), > > LSM_HOOK_INIT(task_alloc, selinux_task_alloc), > LSM_HOOK_INIT(cred_prepare, selinux_cred_prepare), > - LSM_HOOK_INIT(cred_transfer, selinux_cred_transfer), > LSM_HOOK_INIT(cred_getsecid, selinux_cred_getsecid), > LSM_HOOK_INIT(kernel_act_as, selinux_kernel_act_as), > LSM_HOOK_INIT(kernel_create_files_as, selinux_kernel_create_files_as), > LSM_HOOK_INIT(kernel_module_request, selinux_kernel_module_request), > LSM_HOOK_INIT(kernel_load_data, selinux_kernel_load_data), > LSM_HOOK_INIT(kernel_read_file, selinux_kernel_read_file), > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index 4164699cd4f6..4cc658deb08b 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -2050,27 +2050,12 @@ static int smack_file_open(struct file *file) > } > > /* > * Task hooks > */ > > -/** > - * smack_cred_alloc_blank - "allocate" blank task-level security credentials > - * @cred: the new credentials > - * @gfp: the atomicity of any memory allocations > - * > - * Prepare a blank set of credentials for modification. This must allocate all > - * the memory the LSM module might require such that cred_transfer() can > - * complete without error. > - */ > -static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp) > -{ > - init_task_smack(smack_cred(cred), NULL, NULL); > - return 0; > -} > - > > /** > * smack_cred_free - "free" task-level security credentials > * @cred: the credentials in question > * > */ > @@ -2113,27 +2098,12 @@ static int smack_cred_prepare(struct cred *new, const struct cred *old, > > rc = smk_copy_relabel(&new_tsp->smk_relabel, &old_tsp->smk_relabel, > gfp); > return rc; > } > > -/** > - * smack_cred_transfer - Transfer the old credentials to the new credentials > - * @new: the new credentials > - * @old: the original credentials > - * > - * Fill in a set of blank credentials from another set of credentials. > - */ > -static void smack_cred_transfer(struct cred *new, const struct cred *old) > -{ > - struct task_smack *old_tsp = smack_cred(old); > - struct task_smack *new_tsp = smack_cred(new); > - > - init_task_smack(new_tsp, old_tsp->smk_task, old_tsp->smk_task); > -} > - > /** > * smack_cred_getsecid - get the secid corresponding to a creds structure > * @cred: the object creds > * @secid: where to put the result > * > * Sets the secid to contain a u32 version of the smack label. > @@ -5107,16 +5077,14 @@ static struct security_hook_list smack_hooks[] __ro_after_init = { > LSM_HOOK_INIT(file_set_fowner, smack_file_set_fowner), > LSM_HOOK_INIT(file_send_sigiotask, smack_file_send_sigiotask), > LSM_HOOK_INIT(file_receive, smack_file_receive), > > LSM_HOOK_INIT(file_open, smack_file_open), > > - LSM_HOOK_INIT(cred_alloc_blank, smack_cred_alloc_blank), Not going through everything but can we e.g. make a separe SMACK patch prepending? > LSM_HOOK_INIT(cred_free, smack_cred_free), > LSM_HOOK_INIT(cred_prepare, smack_cred_prepare), > - LSM_HOOK_INIT(cred_transfer, smack_cred_transfer), > LSM_HOOK_INIT(cred_getsecid, smack_cred_getsecid), > LSM_HOOK_INIT(kernel_act_as, smack_kernel_act_as), > LSM_HOOK_INIT(kernel_create_files_as, smack_kernel_create_files_as), > LSM_HOOK_INIT(task_setpgid, smack_task_setpgid), > LSM_HOOK_INIT(task_getpgid, smack_task_getpgid), > LSM_HOOK_INIT(task_getsid, smack_task_getsid), > > --- > base-commit: c0ecd6388360d930440cc5554026818895199923 > change-id: 20240802-remove-cred-transfer-493a3b696da2 BR, Jarkko
