From: Paul Moore <paul@paul-moore.com> To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Kumar Kartikeya Dwivedi <memxor@gmail.com>, Jens Axboe <axboe@kernel.dk>, Alexander Viro <viro@zeniv.linux.org.uk> Subject: [RFC PATCH 8/9] selinux: add support for the io_uring access controls Date: Fri, 21 May 2021 17:50:31 -0400 [thread overview] Message-ID: <162163383147.8379.1567341725602837940.stgit@sifl> (raw) In-Reply-To: <162163367115.8379.8459012634106035341.stgit@sifl> WARNING - This is a work in progress, this patch, including the description, may be incomplete or even incorrect. You have been warned. This patch implements two new io_uring access controls, specifically support for controlling the io_uring "personalities" and IORING_SETUP_SQPOLL. Controlling the sharing of io_urings themselves is handled via the normal file/inode labeling and sharing mechanisms. The io_uring { override_creds } permission restricts which domains the subject domain can use to override it's own credentials. Granting a domain the io_uring { override_creds } permission allows it to impersonate another domain in io_uring operations. The io_uring { sqpoll } permission restricts which domains can create asynchronous io_uring polling threads. This is important from a security perspective as operations queued by this asynchronous thread inherit the credentials of the thread creator by default; if an io_uring is shared across process/domain boundaries this could result in one domain impersonating another. Controlling the creation of sqpoll threads, and the sharing of io_urings across processes, allow policy authors to restrict the ability of one domain to impersonate another via io_uring. As a quick summary, this patch adds a new object class with two permissions: io_uring { override_creds sqpoll } These permissions can be seen in the two simple policy statements below: allow domA_t domB_t : io_uring { override_creds }; allow domA_t self : io_uring { sqpoll }; Signed-off-by: Paul Moore <paul@paul-moore.com> --- security/selinux/hooks.c | 67 +++++++++++++++++++++++++++++++++++ security/selinux/include/classmap.h | 2 + 2 files changed, 69 insertions(+) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index eaea837d89d1..696130972e4d 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -7115,6 +7115,68 @@ static int selinux_perf_event_write(struct perf_event *event) } #endif +#ifdef CONFIG_IO_URING + +#if 1 +/* XXX - dump_creds() is for debugging only, remove before committing */ +static void dump_creds(const struct cred *cred) +{ + u32 secid; + char *ctx = NULL; + unsigned int ctx_len = 0; + + security_cred_getsecid(cred, &secid); + if (secid) + security_secid_to_secctx(secid, &ctx, &ctx_len); + + printk(KERN_ERR "CRED: ->security is %s\n", (ctx ? : "(error)")); + + if (ctx) + security_release_secctx(ctx, ctx_len); +} +#endif + +/** + * selinux_uring_override_creds - check the requested cred override + * @new: the target creds + * + * Check to see if the current task is allowed to override it's credentials + * to service an io_uring operation. + */ +int selinux_uring_override_creds(const struct cred *new) +{ +#if 1 + /* XXX - debug only code, remove before committing */ + pr_err("PMD: selinux_uring_override_creds()\n"); + pr_err("PMD: >>> CURRENT\n"); + dump_creds(current_cred()); + pr_err("PMD: >>> NEW\n"); + dump_creds(new); +#endif + return avc_has_perm(&selinux_state, current_sid(), cred_sid(new), + SECCLASS_IO_URING, IO_URING__OVERRIDE_CREDS, NULL); +} + +/** + * selinux_uring_sqpoll - check if a io_uring polling thread can be created + * + * Check to see if the current task is allowed to create a new io_uring + * kernel polling thread. + */ +int selinux_uring_sqpoll(void) +{ + int sid = current_sid(); +#if 1 + /* XXX - debug only code, remove before committing */ + pr_err("PMD: selinux_uring_sqpoll()\n"); + pr_err("PMD: >>> CURRENT\n"); + dump_creds(current_cred()); +#endif + return avc_has_perm(&selinux_state, sid, sid, + SECCLASS_IO_URING, IO_URING__SQPOLL, NULL); +} +#endif /* CONFIG_IO_URING */ + /* * IMPORTANT NOTE: When adding new hooks, please be careful to keep this order: * 1. any hooks that don't belong to (2.) or (3.) below, @@ -7353,6 +7415,11 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(perf_event_write, selinux_perf_event_write), #endif +#ifdef CONFIG_IO_URING + LSM_HOOK_INIT(uring_override_creds, selinux_uring_override_creds), + LSM_HOOK_INIT(uring_sqpoll, selinux_uring_sqpoll), +#endif + LSM_HOOK_INIT(locked_down, selinux_lockdown), /* diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index 62d19bccf3de..3314ad72279d 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -252,6 +252,8 @@ struct security_class_mapping secclass_map[] = { { "integrity", "confidentiality", NULL } }, { "anon_inode", { COMMON_FILE_PERMS, NULL } }, + { "io_uring", + { "override_creds", "sqpoll", NULL } }, { NULL } };
WARNING: multiple messages have this Message-ID (diff)
From: Paul Moore <paul@paul-moore.com> To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Kumar Kartikeya Dwivedi <memxor@gmail.com>, Jens Axboe <axboe@kernel.dk>, Alexander Viro <viro@zeniv.linux.org.uk> Subject: [RFC PATCH 8/9] selinux: add support for the io_uring access controls Date: Fri, 21 May 2021 17:50:31 -0400 [thread overview] Message-ID: <162163383147.8379.1567341725602837940.stgit@sifl> (raw) In-Reply-To: <162163367115.8379.8459012634106035341.stgit@sifl> WARNING - This is a work in progress, this patch, including the description, may be incomplete or even incorrect. You have been warned. This patch implements two new io_uring access controls, specifically support for controlling the io_uring "personalities" and IORING_SETUP_SQPOLL. Controlling the sharing of io_urings themselves is handled via the normal file/inode labeling and sharing mechanisms. The io_uring { override_creds } permission restricts which domains the subject domain can use to override it's own credentials. Granting a domain the io_uring { override_creds } permission allows it to impersonate another domain in io_uring operations. The io_uring { sqpoll } permission restricts which domains can create asynchronous io_uring polling threads. This is important from a security perspective as operations queued by this asynchronous thread inherit the credentials of the thread creator by default; if an io_uring is shared across process/domain boundaries this could result in one domain impersonating another. Controlling the creation of sqpoll threads, and the sharing of io_urings across processes, allow policy authors to restrict the ability of one domain to impersonate another via io_uring. As a quick summary, this patch adds a new object class with two permissions: io_uring { override_creds sqpoll } These permissions can be seen in the two simple policy statements below: allow domA_t domB_t : io_uring { override_creds }; allow domA_t self : io_uring { sqpoll }; Signed-off-by: Paul Moore <paul@paul-moore.com> --- security/selinux/hooks.c | 67 +++++++++++++++++++++++++++++++++++ security/selinux/include/classmap.h | 2 + 2 files changed, 69 insertions(+) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index eaea837d89d1..696130972e4d 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -7115,6 +7115,68 @@ static int selinux_perf_event_write(struct perf_event *event) } #endif +#ifdef CONFIG_IO_URING + +#if 1 +/* XXX - dump_creds() is for debugging only, remove before committing */ +static void dump_creds(const struct cred *cred) +{ + u32 secid; + char *ctx = NULL; + unsigned int ctx_len = 0; + + security_cred_getsecid(cred, &secid); + if (secid) + security_secid_to_secctx(secid, &ctx, &ctx_len); + + printk(KERN_ERR "CRED: ->security is %s\n", (ctx ? : "(error)")); + + if (ctx) + security_release_secctx(ctx, ctx_len); +} +#endif + +/** + * selinux_uring_override_creds - check the requested cred override + * @new: the target creds + * + * Check to see if the current task is allowed to override it's credentials + * to service an io_uring operation. + */ +int selinux_uring_override_creds(const struct cred *new) +{ +#if 1 + /* XXX - debug only code, remove before committing */ + pr_err("PMD: selinux_uring_override_creds()\n"); + pr_err("PMD: >>> CURRENT\n"); + dump_creds(current_cred()); + pr_err("PMD: >>> NEW\n"); + dump_creds(new); +#endif + return avc_has_perm(&selinux_state, current_sid(), cred_sid(new), + SECCLASS_IO_URING, IO_URING__OVERRIDE_CREDS, NULL); +} + +/** + * selinux_uring_sqpoll - check if a io_uring polling thread can be created + * + * Check to see if the current task is allowed to create a new io_uring + * kernel polling thread. + */ +int selinux_uring_sqpoll(void) +{ + int sid = current_sid(); +#if 1 + /* XXX - debug only code, remove before committing */ + pr_err("PMD: selinux_uring_sqpoll()\n"); + pr_err("PMD: >>> CURRENT\n"); + dump_creds(current_cred()); +#endif + return avc_has_perm(&selinux_state, sid, sid, + SECCLASS_IO_URING, IO_URING__SQPOLL, NULL); +} +#endif /* CONFIG_IO_URING */ + /* * IMPORTANT NOTE: When adding new hooks, please be careful to keep this order: * 1. any hooks that don't belong to (2.) or (3.) below, @@ -7353,6 +7415,11 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(perf_event_write, selinux_perf_event_write), #endif +#ifdef CONFIG_IO_URING + LSM_HOOK_INIT(uring_override_creds, selinux_uring_override_creds), + LSM_HOOK_INIT(uring_sqpoll, selinux_uring_sqpoll), +#endif + LSM_HOOK_INIT(locked_down, selinux_lockdown), /* diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index 62d19bccf3de..3314ad72279d 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -252,6 +252,8 @@ struct security_class_mapping secclass_map[] = { { "integrity", "confidentiality", NULL } }, { "anon_inode", { COMMON_FILE_PERMS, NULL } }, + { "io_uring", + { "override_creds", "sqpoll", NULL } }, { NULL } }; -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit
next prev parent reply other threads:[~2021-05-21 21:50 UTC|newest] Thread overview: 144+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-21 21:49 [RFC PATCH 0/9] Add LSM access controls and auditing to io_uring Paul Moore 2021-05-21 21:49 ` Paul Moore 2021-05-21 21:49 ` [RFC PATCH 1/9] audit: prepare audit_context for use in calling contexts beyond syscalls Paul Moore 2021-05-21 21:49 ` Paul Moore 2021-05-21 21:49 ` [RFC PATCH 2/9] audit,io_uring,io-wq: add some basic audit support to io_uring Paul Moore 2021-05-21 21:49 ` [RFC PATCH 2/9] audit, io_uring, io-wq: " Paul Moore 2021-05-22 0:22 ` [RFC PATCH 2/9] audit,io_uring,io-wq: " Pavel Begunkov 2021-05-22 0:22 ` Pavel Begunkov 2021-05-22 2:36 ` Paul Moore 2021-05-22 2:36 ` Paul Moore 2021-05-23 20:26 ` Pavel Begunkov 2021-05-23 20:26 ` Pavel Begunkov 2021-05-24 19:59 ` Paul Moore 2021-05-24 19:59 ` Paul Moore 2021-05-25 8:27 ` Pavel Begunkov 2021-05-25 8:27 ` Pavel Begunkov 2021-05-25 14:53 ` Paul Moore 2021-05-25 14:53 ` Paul Moore 2021-05-26 1:11 ` Jens Axboe 2021-05-26 1:11 ` Jens Axboe 2021-05-26 2:04 ` Paul Moore 2021-05-26 2:04 ` Paul Moore 2021-05-26 10:19 ` Pavel Begunkov 2021-05-26 10:19 ` Pavel Begunkov 2021-05-26 14:38 ` Paul Moore 2021-05-26 14:38 ` Paul Moore 2021-05-26 15:11 ` Steve Grubb 2021-05-26 15:11 ` [RFC PATCH 2/9] audit, io_uring, io-wq: " Steve Grubb 2021-05-26 15:17 ` [RFC PATCH 2/9] audit,io_uring,io-wq: " Stefan Metzmacher 2021-05-26 15:17 ` Stefan Metzmacher 2021-05-26 15:49 ` Richard Guy Briggs 2021-05-26 15:49 ` Richard Guy Briggs 2021-05-26 17:22 ` Jens Axboe 2021-05-26 17:22 ` Jens Axboe 2021-05-27 17:27 ` Richard Guy Briggs 2021-05-27 17:27 ` Richard Guy Briggs 2021-05-26 15:49 ` Victor Stewart 2021-05-26 15:49 ` Victor Stewart 2021-05-26 16:38 ` Casey Schaufler 2021-05-26 16:38 ` Casey Schaufler 2021-05-26 17:15 ` Jens Axboe 2021-05-26 17:15 ` Jens Axboe 2021-05-26 17:31 ` Jens Axboe 2021-05-26 17:31 ` Jens Axboe 2021-05-26 17:54 ` Jens Axboe 2021-05-26 17:54 ` Jens Axboe 2021-05-26 18:01 ` Jens Axboe 2021-05-26 18:01 ` Jens Axboe 2021-05-26 18:44 ` Paul Moore 2021-05-26 18:44 ` Paul Moore 2021-05-26 18:57 ` Pavel Begunkov 2021-05-26 18:57 ` Pavel Begunkov 2021-05-26 19:10 ` Paul Moore 2021-05-26 19:10 ` Paul Moore 2021-05-26 19:44 ` Jens Axboe 2021-05-26 19:44 ` Jens Axboe 2021-05-26 20:19 ` Paul Moore 2021-05-26 20:19 ` Paul Moore 2021-05-28 16:02 ` Paul Moore 2021-05-28 16:02 ` Paul Moore 2021-06-02 8:26 ` Pavel Begunkov 2021-06-02 8:26 ` Pavel Begunkov 2021-06-02 15:46 ` Richard Guy Briggs 2021-06-02 15:46 ` Richard Guy Briggs 2021-06-03 10:39 ` Pavel Begunkov 2021-06-03 10:39 ` Pavel Begunkov 2021-06-02 19:46 ` Paul Moore 2021-06-02 19:46 ` Paul Moore 2021-06-03 10:51 ` Pavel Begunkov 2021-06-03 10:51 ` Pavel Begunkov 2021-06-03 15:54 ` Casey Schaufler 2021-06-03 15:54 ` Casey Schaufler 2021-06-03 15:54 ` Jens Axboe 2021-06-03 15:54 ` Jens Axboe 2021-06-04 5:04 ` Paul Moore 2021-06-04 5:04 ` Paul Moore 2021-05-26 18:38 ` Paul Moore 2021-05-26 18:38 ` Paul Moore 2021-06-02 17:29 ` [RFC PATCH 2/9] audit, io_uring, io-wq: " Richard Guy Briggs 2021-06-02 17:29 ` Richard Guy Briggs 2021-06-02 20:46 ` Paul Moore 2021-06-02 20:46 ` Paul Moore 2021-08-25 1:21 ` Richard Guy Briggs 2021-08-25 1:21 ` Richard Guy Briggs 2021-08-25 19:41 ` Paul Moore 2021-08-25 19:41 ` Paul Moore 2021-05-21 21:50 ` [RFC PATCH 3/9] audit: dev/test patch to force io_uring auditing Paul Moore 2021-05-21 21:50 ` Paul Moore 2021-05-21 21:50 ` [RFC PATCH 4/9] audit: add filtering for io_uring records Paul Moore 2021-05-21 21:50 ` Paul Moore 2021-05-28 22:35 ` Richard Guy Briggs 2021-05-28 22:35 ` Richard Guy Briggs 2021-05-30 15:26 ` Paul Moore 2021-05-30 15:26 ` Paul Moore 2021-05-31 13:44 ` Richard Guy Briggs 2021-05-31 13:44 ` Richard Guy Briggs 2021-06-02 1:40 ` Paul Moore 2021-06-02 1:40 ` Paul Moore 2021-06-02 15:37 ` Richard Guy Briggs 2021-06-02 15:37 ` Richard Guy Briggs 2021-06-02 17:20 ` Paul Moore 2021-06-02 17:20 ` Paul Moore 2021-05-31 13:44 ` [PATCH 1/2] audit: add filtering for io_uring records, addendum Richard Guy Briggs 2021-05-31 13:44 ` Richard Guy Briggs 2021-05-31 16:08 ` kernel test robot 2021-05-31 16:08 ` kernel test robot 2021-05-31 16:08 ` kernel test robot 2021-05-31 17:38 ` kernel test robot 2021-05-31 17:38 ` kernel test robot 2021-05-31 17:38 ` kernel test robot 2021-06-07 23:15 ` Paul Moore 2021-06-07 23:15 ` Paul Moore 2021-06-08 12:55 ` Richard Guy Briggs 2021-06-08 12:55 ` Richard Guy Briggs 2021-06-09 2:45 ` Paul Moore 2021-06-09 2:45 ` Paul Moore 2021-05-31 13:44 ` [PATCH 2/2] audit: block PERM fields being used with io_uring filtering Richard Guy Briggs 2021-05-31 13:44 ` Richard Guy Briggs 2021-05-21 21:50 ` [RFC PATCH 5/9] fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure() Paul Moore 2021-05-21 21:50 ` Paul Moore 2021-05-21 21:50 ` [RFC PATCH 6/9] io_uring: convert io_uring to the secure anon inode interface Paul Moore 2021-05-21 21:50 ` Paul Moore 2021-05-21 21:50 ` [RFC PATCH 7/9] lsm,io_uring: add LSM hooks to io_uring Paul Moore 2021-05-21 21:50 ` Paul Moore 2021-05-26 14:48 ` Stefan Metzmacher 2021-05-26 14:48 ` Stefan Metzmacher 2021-05-26 20:45 ` Paul Moore 2021-05-26 20:45 ` Paul Moore 2021-05-21 21:50 ` Paul Moore [this message] 2021-05-21 21:50 ` [RFC PATCH 8/9] selinux: add support for the io_uring access controls Paul Moore 2021-05-21 21:50 ` [RFC PATCH 9/9] Smack: Brutalist io_uring support with debug Paul Moore 2021-05-21 21:50 ` Paul Moore 2021-05-22 0:53 ` [RFC PATCH 0/9] Add LSM access controls and auditing to io_uring Tetsuo Handa 2021-05-22 0:53 ` Tetsuo Handa 2021-05-22 2:06 ` Paul Moore 2021-05-22 2:06 ` Paul Moore 2021-05-26 15:00 ` Jeff Moyer 2021-05-26 15:00 ` Jeff Moyer 2021-05-26 18:49 ` Paul Moore 2021-05-26 18:49 ` Paul Moore 2021-05-26 19:07 ` Jeff Moyer 2021-05-26 19:07 ` Jeff Moyer 2021-05-26 19:10 ` Paul Moore 2021-05-26 19:10 ` Paul Moore
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