| Message ID | 162871494794.63873.18299137802334845525.stgit@olly (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | Add LSM access controls and auditing to io_uring | expand |
On Wed, Aug 11, 2021 at 4:49 PM Paul Moore <paul@paul-moore.com> wrote: > > From: Casey Schaufler <casey@schaufler-ca.com> > > Add Smack privilege checks for io_uring. Use CAP_MAC_OVERRIDE > for the override_creds case and CAP_MAC_ADMIN for creating a > polling thread. These choices are based on conjecture regarding > the intent of the surrounding code. > > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> > [PM: make the smack_uring_* funcs static] > Signed-off-by: Paul Moore <paul@paul-moore.com> > > --- > v2: > - made the smack_uring_* funcs static > v1: > - initial draft > --- > security/smack/smack_lsm.c | 64 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 64 insertions(+) > > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index 223a6da0e6dc..7fb094098f38 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -4691,6 +4691,66 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode, > return 0; > } > > +#ifdef CONFIG_IO_URING > +/** > + * smack_uring_override_creds - Is io_uring cred override allowed? > + * @new: the target creds > + * > + * Check to see if the current task is allowed to override it's credentials > + * to service an io_uring operation. > + */ > +static int smack_uring_override_creds(const struct cred *new) > +{ > + struct task_smack *tsp = smack_cred(current_cred()); > + struct task_smack *nsp = smack_cred(new); > + > +#if 1 > + if (tsp->smk_task == nsp->smk_task) > + pr_info("%s: Smack matches %s\n", __func__, > + tsp->smk_task->smk_known); > + else > + pr_info("%s: Smack override check %s to %s\n", __func__, > + tsp->smk_task->smk_known, nsp->smk_task->smk_known); > +#endif Casey, with the idea of posting a v3 towards the end of the merge window next week, without the RFC tag and with the intention of merging it into -next during the first/second week of the -rcX phase, do you have any objections to me removing the debug code (#if 1 ... #endif) from your patch? Did you have any other changes? -- paul moore www.paul-moore.com
On 8/31/2021 7:44 AM, Paul Moore wrote: > On Wed, Aug 11, 2021 at 4:49 PM Paul Moore <paul@paul-moore.com> wrote: >> From: Casey Schaufler <casey@schaufler-ca.com> >> >> Add Smack privilege checks for io_uring. Use CAP_MAC_OVERRIDE >> for the override_creds case and CAP_MAC_ADMIN for creating a >> polling thread. These choices are based on conjecture regarding >> the intent of the surrounding code. >> >> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> >> [PM: make the smack_uring_* funcs static] >> Signed-off-by: Paul Moore <paul@paul-moore.com> >> >> --- >> v2: >> - made the smack_uring_* funcs static >> v1: >> - initial draft >> --- >> security/smack/smack_lsm.c | 64 ++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 64 insertions(+) >> >> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c >> index 223a6da0e6dc..7fb094098f38 100644 >> --- a/security/smack/smack_lsm.c >> +++ b/security/smack/smack_lsm.c >> @@ -4691,6 +4691,66 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode, >> return 0; >> } >> >> +#ifdef CONFIG_IO_URING >> +/** >> + * smack_uring_override_creds - Is io_uring cred override allowed? >> + * @new: the target creds >> + * >> + * Check to see if the current task is allowed to override it's credentials >> + * to service an io_uring operation. >> + */ >> +static int smack_uring_override_creds(const struct cred *new) >> +{ >> + struct task_smack *tsp = smack_cred(current_cred()); >> + struct task_smack *nsp = smack_cred(new); >> + >> +#if 1 >> + if (tsp->smk_task == nsp->smk_task) >> + pr_info("%s: Smack matches %s\n", __func__, >> + tsp->smk_task->smk_known); >> + else >> + pr_info("%s: Smack override check %s to %s\n", __func__, >> + tsp->smk_task->smk_known, nsp->smk_task->smk_known); >> +#endif > Casey, with the idea of posting a v3 towards the end of the merge > window next week, without the RFC tag and with the intention of > merging it into -next during the first/second week of the -rcX phase, > do you have any objections to me removing the debug code (#if 1 ... > #endif) from your patch? Did you have any other changes? I have no other changes. And yes, the debug code should be stripped. Thank you. > > > -- > paul moore > www.paul-moore.com
On Tue, Aug 31, 2021 at 11:03 AM Casey Schaufler <casey@schaufler-ca.com> wrote: > On 8/31/2021 7:44 AM, Paul Moore wrote: > > > > Casey, with the idea of posting a v3 towards the end of the merge > > window next week, without the RFC tag and with the intention of > > merging it into -next during the first/second week of the -rcX phase, > > do you have any objections to me removing the debug code (#if 1 ... > > #endif) from your patch? Did you have any other changes? > > I have no other changes. And yes, the debug code should be stripped. > Thank you. Great, I'll remove that code for the v3 dump.
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 223a6da0e6dc..7fb094098f38 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4691,6 +4691,66 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode, return 0; } +#ifdef CONFIG_IO_URING +/** + * smack_uring_override_creds - Is io_uring cred override allowed? + * @new: the target creds + * + * Check to see if the current task is allowed to override it's credentials + * to service an io_uring operation. + */ +static int smack_uring_override_creds(const struct cred *new) +{ + struct task_smack *tsp = smack_cred(current_cred()); + struct task_smack *nsp = smack_cred(new); + +#if 1 + if (tsp->smk_task == nsp->smk_task) + pr_info("%s: Smack matches %s\n", __func__, + tsp->smk_task->smk_known); + else + pr_info("%s: Smack override check %s to %s\n", __func__, + tsp->smk_task->smk_known, nsp->smk_task->smk_known); +#endif + /* + * Allow the degenerate case where the new Smack value is + * the same as the current Smack value. + */ + if (tsp->smk_task == nsp->smk_task) + return 0; + +#if 1 + pr_info("%s: Smack sqpoll %s\n", __func__, + smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred()) ? + "ok by Smack" : "disallowed (No CAP_MAC_OVERRIDE)"); +#endif + if (smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred())) + return 0; + + return -EPERM; +} + +/** + * smack_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. + */ +static int smack_uring_sqpoll(void) +{ +#if 1 + pr_info("%s: Smack new ring %s\n", __func__, + smack_privileged_cred(CAP_MAC_ADMIN, current_cred()) ? + "ok by Smack" : "disallowed (No CAP_MAC_ADMIN)"); +#endif + if (smack_privileged_cred(CAP_MAC_ADMIN, current_cred())) + return 0; + + return -EPERM; +} + +#endif /* CONFIG_IO_URING */ + struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = { .lbs_cred = sizeof(struct task_smack), .lbs_file = sizeof(struct smack_known *), @@ -4843,6 +4903,10 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(inode_copy_up, smack_inode_copy_up), LSM_HOOK_INIT(inode_copy_up_xattr, smack_inode_copy_up_xattr), LSM_HOOK_INIT(dentry_create_files_as, smack_dentry_create_files_as), +#ifdef CONFIG_IO_URING + LSM_HOOK_INIT(uring_override_creds, smack_uring_override_creds), + LSM_HOOK_INIT(uring_sqpoll, smack_uring_sqpoll), +#endif };