From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B48A53BBC1; Thu, 15 Aug 2024 18:12:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723745547; cv=none; b=FBoe0O56UxbjY5ncb/9ISPEuYIYVaLuRy5beRHV48MnicnOdrWlAEkxpAZEOoQR4GCUCdgxkfkIAJfpBd7eGjLNYcG8+URstpYQujt2Y6PLFY4PfNAIngflGthjpf7daZyp82WJf9l4pVn+bbW5k0epaiTKBNMQ36KsoNB7HaGc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723745547; c=relaxed/simple; bh=fMqj5NIFdJA5Vk5aEHchBIKt7Z0tV8H75qpAOsYUcV0=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=AAvWFpYoHdoLijXRySmf3fM2MMvjt/E1du951OmeVZb0aLoJhQ/kaivQo0mi5kH4/10Ys2sGxpSZvs/6DSjGb2UYBW0KuIqoyhdsX09oMnwCyyUvu9z/07Ts6ZBvECyOXFRlV4Q3lYYQIBGoom2IgP+yOb8Ng84mreaCOrInXy8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=X7r4+VAf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="X7r4+VAf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7AE5C4AF0D; Thu, 15 Aug 2024 18:12:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723745547; bh=fMqj5NIFdJA5Vk5aEHchBIKt7Z0tV8H75qpAOsYUcV0=; h=Date:Cc:Subject:From:To:References:In-Reply-To:From; b=X7r4+VAfOEl9dlglr36HV7AlPmQAqm6bMYTKqnPIvIL56vpalahuVRS1UqGZGGQUp oI1d/RWCcswo+HFtg4rLarHx5Cim1RzgaRX1ZLnA+VMD8uadyRTuI43dh4ajZEFkCW 1fzsvdeGgPV+Oto5hmts4jRwaVepzlBGsLl1uZLRV8BzKHHxfY0hDOII45bIGUmrcx Gm5gNLt0ijM0W9xE6TPHmQKP3lyhPHOiU2gq/zLqNlEXSF7W0gwutSsMCw66Xrlv6B etflFniO4NFdtGB6rQd+dx2JH2m9uRPwsVpOoL9gUu1whM38gC7xmy40JwbupiCyIG r940ohEohNJPQ== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 15 Aug 2024 21:12:23 +0300 Message-Id: Cc: , , , , Subject: Re: [PATCH v2 2/2] security: remove unused cred_alloc_blank/cred_transfer helpers From: "Jarkko Sakkinen" To: "Jann Horn" , "Paul Moore" , "James Morris" , "Serge E. Hallyn" , "John Johansen" , "David Howells" , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , =?utf-8?q?G=C3=BCnther_Noack?= , "Stephen Smalley" , "Ondrej Mosnacek" , "Casey Schaufler" X-Mailer: aerc 0.17.0 References: <20240805-remove-cred-transfer-v2-0-a2aa1d45e6b8@google.com> <20240805-remove-cred-transfer-v2-2-a2aa1d45e6b8@google.com> In-Reply-To: <20240805-remove-cred-transfer-v2-2-a2aa1d45e6b8@google.com> On Mon Aug 5, 2024 at 2:54 PM EEST, Jann Horn wrote: > Now that they're unused thanks to the preceding commit, remove > cred_alloc_blank(), security_transfer_creds(), and the corresponding LSM > hook implementations. > > Signed-off-by: Jann Horn > --- > 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/landlock/cred.c | 11 ++--------- > security/security.c | 35 ----------------------------------- > security/selinux/hooks.c | 12 ------------ > security/smack/smack_lsm.c | 32 -------------------------------- > 9 files changed, 2 insertions(+), 146 deletions(-) > > 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; > =20 > 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 *s= ecid) > 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 con= tents) > 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_fl= ags); > 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 *inod= e); > 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; > } > =20 > static inline void security_task_free(struct task_struct *task) > { } > =20 > -static inline int security_cred_alloc_blank(struct cred *cred, gfp_t gfp= ) > -{ > - return 0; > -} > - > static inline void security_cred_free(struct cred *cred) > { } > =20 > static inline int security_prepare_creds(struct cred *new, > const struct cred *old, > gfp_t gfp) > { > return 0; > } > =20 > -static inline void security_transfer_creds(struct cred *new, > - const struct cred *old) > -{ > -} > - > static inline void security_cred_getsecid(const struct cred *c, u32 *sec= id) > { > *secid =3D 0; > } > =20 > 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) > =20 > rcu_read_unlock(); > return cred; > } > EXPORT_SYMBOL(get_task_cred); > =20 > -/* > - * Allocate blank credentials, such that the credentials can be filled i= n at a > - * later date without risk of ENOMEM. > - */ > -struct cred *cred_alloc_blank(void) > -{ > - struct cred *new; > - > - new =3D 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 cre= ds > * shouldn't generally be modified directly, therefore this function is = used to > * prepare a new copy, which the caller then modifies and then commits b= y > 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); > } > =20 > -/* > - * 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 *ol= d, > gfp_t gfp) > { > set_cred_label(new, aa_get_newest_label(cred_label(old))); > return 0; > } > =20 > -/* > - * 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) > { > =20 > aa_free_task_ctx(task_ctx(task)); > } > =20 > @@ -1504,16 +1487,14 @@ static struct security_hook_list apparmor_hooks[]= __ro_after_init =3D { > 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 > =20 > - 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), > =20 > 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), > =20 > LSM_HOOK_INIT(task_free, apparmor_task_free), > 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 @@ > =20 > #include "common.h" > #include "cred.h" > #include "ruleset.h" > #include "setup.h" > =20 > -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 =3D landlock_cred(old)->domain; > =20 > if (old_dom) { > landlock_get_ruleset(old_dom); > landlock_cred(new)->domain =3D 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; > } > =20 > static void hook_cred_free(struct cred *const cred) > { > struct landlock_ruleset *const dom =3D landlock_cred(cred)->domain; > =20 > if (dom) > landlock_put_ruleset_deferred(dom); > } > =20 > static struct security_hook_list landlock_hooks[] __ro_after_init =3D { > LSM_HOOK_INIT(cred_prepare, hook_cred_prepare), > - LSM_HOOK_INIT(cred_transfer, hook_cred_transfer), > LSM_HOOK_INIT(cred_free, hook_cred_free), > }; > =20 > __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); > =20 > kfree(task->security); > task->security =3D NULL; > } > =20 > -/** > - * security_cred_alloc_blank() - Allocate the min memory to allow cred_t= ransfer > - * @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 =3D lsm_cred_alloc(cred, gfp); > - > - if (rc) > - return rc; > - > - rc =3D 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 resour= ces > * @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, cons= t struct cred *old, gfp_t gfp) > rc =3D call_int_hook(cred_prepare, new, old, gfp); > if (unlikely(rc)) > security_cred_free(new); > return rc; > } > =20 > -/** > - * 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 o= f > 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 =3D selinux_cred(new); > =20 > *tsec =3D *old_tsec; > return 0; > } > =20 > -/* > - * transfer the SELinux data to a blank set of creds > - */ > -static void selinux_cred_transfer(struct cred *new, const struct cred *o= ld) > -{ > - const struct task_security_struct *old_tsec =3D selinux_cred(old); > - struct task_security_struct *tsec =3D selinux_cred(new); > - > - *tsec =3D *old_tsec; > -} > - > static void selinux_cred_getsecid(const struct cred *c, u32 *secid) > { > *secid =3D cred_sid(c); > } > =20 > /* > @@ -7213,13 +7202,12 @@ static struct security_hook_list selinux_hooks[] = __ro_after_init =3D { > LSM_HOOK_INIT(file_receive, selinux_file_receive), > =20 > LSM_HOOK_INIT(file_open, selinux_file_open), > =20 > 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) > } > =20 > /* > * Task hooks > */ > =20 > -/** > - * smack_cred_alloc_blank - "allocate" blank task-level security credent= ials > - * @cred: the new credentials > - * @gfp: the atomicity of any memory allocations > - * > - * Prepare a blank set of credentials for modification. This must alloc= ate 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; > -} > - > =20 > /** > * 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, c= onst struct cred *old, > =20 > rc =3D smk_copy_relabel(&new_tsp->smk_relabel, &old_tsp->smk_relabel, > gfp); > return rc; > } > =20 > -/** > - * smack_cred_transfer - Transfer the old credentials to the new credent= ials > - * @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 =3D smack_cred(old); > - struct task_smack *new_tsp =3D 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 structur= e > * @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 =3D { > 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), > =20 > LSM_HOOK_INIT(file_open, smack_file_open), > =20 > - LSM_HOOK_INIT(cred_alloc_blank, smack_cred_alloc_blank), > 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), I'll give this reviewd-by as soon as getting some feedback David on 1/2. I mean this is dead obvious with a condition. BR, Jarkko