| Message ID | 20220420140633.753772-5-stefanb@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ima: Namespace IMA with audit support in IMA-ns | expand |
On Wed, Apr 20, 2022 at 10:06:11AM -0400, Stefan Berger wrote: > The architecture-specific policy rules, currently defined for EFI and > powerpc, require the kexec kernel image and kernel modules to be > validly signed and measured, based on the system's secure boot and/or > trusted boot mode and the IMA_ARCH_POLICY Kconfig option being enabled. > > To avoid special-casing init_ima_ns as much as possible, move the > arch_policy_entry into the ima_namespace. > > When freeing the arch_policy_entry set the pointer to NULL. > > Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> > Acked-by: Christian Brauner <brauner@kernel.org> > Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> > --- > security/integrity/ima/ima.h | 3 +++ > security/integrity/ima/ima_init_ima_ns.c | 1 + > security/integrity/ima/ima_policy.c | 23 +++++++++++------------ > 3 files changed, 15 insertions(+), 12 deletions(-) > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > index 9bcde1a24e74..2305bf223a98 100644 > --- a/security/integrity/ima/ima.h > +++ b/security/integrity/ima/ima.h > @@ -125,6 +125,9 @@ struct ima_namespace { > > struct list_head __rcu *ima_rules; /* Pointer to the current policy */ > int ima_policy_flag; > + > + /* An array of architecture specific rules */ > + struct ima_rule_entry *arch_policy_entry; > } __randomize_layout; > extern struct ima_namespace init_ima_ns; > > diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c > index c919a456b525..ae33621c3955 100644 > --- a/security/integrity/ima/ima_init_ima_ns.c > +++ b/security/integrity/ima/ima_init_ima_ns.c > @@ -15,6 +15,7 @@ static int ima_init_namespace(struct ima_namespace *ns) > INIT_LIST_HEAD(&ns->ima_temp_rules); > ns->ima_rules = (struct list_head __rcu *)(&ns->ima_default_rules); > ns->ima_policy_flag = 0; > + ns->arch_policy_entry = NULL; > > return 0; > } > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c > index 69b19f4d5fee..0a7c61ca3265 100644 > --- a/security/integrity/ima/ima_policy.c > +++ b/security/integrity/ima/ima_policy.c > @@ -228,9 +228,6 @@ static struct ima_rule_entry critical_data_rules[] __ro_after_init = { > {.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC}, > }; > > -/* An array of architecture specific rules */ > -static struct ima_rule_entry *arch_policy_entry __ro_after_init; > - > static int ima_policy __initdata; > > static int __init default_measure_policy_setup(char *str) > @@ -859,9 +856,10 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns) > for (rules = arch_rules; *rules != NULL; rules++) > arch_entries++; > > - arch_policy_entry = kcalloc(arch_entries + 1, > - sizeof(*arch_policy_entry), GFP_KERNEL); > - if (!arch_policy_entry) > + ns->arch_policy_entry = kcalloc(arch_entries + 1, > + sizeof(*ns->arch_policy_entry), > + GFP_KERNEL); > + if (!ns->arch_policy_entry) > return 0; > > /* Convert each policy string rules to struct ima_rule_entry format */ > @@ -871,13 +869,13 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns) > > result = strscpy(rule, *rules, sizeof(rule)); > > - INIT_LIST_HEAD(&arch_policy_entry[i].list); > - result = ima_parse_rule(ns, rule, &arch_policy_entry[i]); > + INIT_LIST_HEAD(&ns->arch_policy_entry[i].list); > + result = ima_parse_rule(ns, rule, &ns->arch_policy_entry[i]); > if (result) { > pr_warn("Skipping unknown architecture policy rule: %s\n", > rule); > - memset(&arch_policy_entry[i], 0, > - sizeof(*arch_policy_entry)); > + memset(&ns->arch_policy_entry[i], 0, > + sizeof(ns->arch_policy_entry[i])); > continue; > } > i++; > @@ -925,7 +923,7 @@ void __init ima_init_policy(struct ima_namespace *ns) > if (!arch_entries) > pr_info("No architecture policies found\n"); > else > - add_rules(ns, arch_policy_entry, arch_entries, > + add_rules(ns, ns->arch_policy_entry, arch_entries, > IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY); > > /* > @@ -1005,7 +1003,8 @@ void ima_update_policy(struct ima_namespace *ns) > * on boot. After loading a custom policy, free the > * architecture specific rules stored as an array. > */ > - kfree(arch_policy_entry); > + kfree(ns->arch_policy_entry); > + ns->arch_policy_entry = NULL; So the thing that prevents multiple racing occurances of the above two lines is that ima_open_policy() sets IMA_FS_BUSY (or returns EBUSY) and then removes this file before clearing the flag, right? Seems good. Reviewed-by: Serge Hallyn <serge@hallyn.com> > } > ima_update_policy_flags(ns); > > -- > 2.34.1
On Fri, May 20, 2022 at 09:46:33PM -0500, Serge E. Hallyn wrote: > On Wed, Apr 20, 2022 at 10:06:11AM -0400, Stefan Berger wrote: > > The architecture-specific policy rules, currently defined for EFI and > > powerpc, require the kexec kernel image and kernel modules to be > > validly signed and measured, based on the system's secure boot and/or > > trusted boot mode and the IMA_ARCH_POLICY Kconfig option being enabled. > > > > To avoid special-casing init_ima_ns as much as possible, move the > > arch_policy_entry into the ima_namespace. > > > > When freeing the arch_policy_entry set the pointer to NULL. > > > > Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> > > Acked-by: Christian Brauner <brauner@kernel.org> > > Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> > > --- > > security/integrity/ima/ima.h | 3 +++ > > security/integrity/ima/ima_init_ima_ns.c | 1 + > > security/integrity/ima/ima_policy.c | 23 +++++++++++------------ > > 3 files changed, 15 insertions(+), 12 deletions(-) > > > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > > index 9bcde1a24e74..2305bf223a98 100644 > > --- a/security/integrity/ima/ima.h > > +++ b/security/integrity/ima/ima.h > > @@ -125,6 +125,9 @@ struct ima_namespace { > > > > struct list_head __rcu *ima_rules; /* Pointer to the current policy */ > > int ima_policy_flag; > > + > > + /* An array of architecture specific rules */ > > + struct ima_rule_entry *arch_policy_entry; > > } __randomize_layout; > > extern struct ima_namespace init_ima_ns; > > > > diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c > > index c919a456b525..ae33621c3955 100644 > > --- a/security/integrity/ima/ima_init_ima_ns.c > > +++ b/security/integrity/ima/ima_init_ima_ns.c > > @@ -15,6 +15,7 @@ static int ima_init_namespace(struct ima_namespace *ns) > > INIT_LIST_HEAD(&ns->ima_temp_rules); > > ns->ima_rules = (struct list_head __rcu *)(&ns->ima_default_rules); > > ns->ima_policy_flag = 0; > > + ns->arch_policy_entry = NULL; > > > > return 0; > > } > > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c > > index 69b19f4d5fee..0a7c61ca3265 100644 > > --- a/security/integrity/ima/ima_policy.c > > +++ b/security/integrity/ima/ima_policy.c > > @@ -228,9 +228,6 @@ static struct ima_rule_entry critical_data_rules[] __ro_after_init = { > > {.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC}, > > }; > > > > -/* An array of architecture specific rules */ > > -static struct ima_rule_entry *arch_policy_entry __ro_after_init; > > - > > static int ima_policy __initdata; > > > > static int __init default_measure_policy_setup(char *str) > > @@ -859,9 +856,10 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns) > > for (rules = arch_rules; *rules != NULL; rules++) > > arch_entries++; > > > > - arch_policy_entry = kcalloc(arch_entries + 1, > > - sizeof(*arch_policy_entry), GFP_KERNEL); > > - if (!arch_policy_entry) > > + ns->arch_policy_entry = kcalloc(arch_entries + 1, > > + sizeof(*ns->arch_policy_entry), > > + GFP_KERNEL); > > + if (!ns->arch_policy_entry) > > return 0; > > > > /* Convert each policy string rules to struct ima_rule_entry format */ > > @@ -871,13 +869,13 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns) > > > > result = strscpy(rule, *rules, sizeof(rule)); > > > > - INIT_LIST_HEAD(&arch_policy_entry[i].list); > > - result = ima_parse_rule(ns, rule, &arch_policy_entry[i]); > > + INIT_LIST_HEAD(&ns->arch_policy_entry[i].list); > > + result = ima_parse_rule(ns, rule, &ns->arch_policy_entry[i]); > > if (result) { > > pr_warn("Skipping unknown architecture policy rule: %s\n", > > rule); > > - memset(&arch_policy_entry[i], 0, > > - sizeof(*arch_policy_entry)); > > + memset(&ns->arch_policy_entry[i], 0, > > + sizeof(ns->arch_policy_entry[i])); > > continue; > > } > > i++; > > @@ -925,7 +923,7 @@ void __init ima_init_policy(struct ima_namespace *ns) > > if (!arch_entries) > > pr_info("No architecture policies found\n"); > > else > > - add_rules(ns, arch_policy_entry, arch_entries, > > + add_rules(ns, ns->arch_policy_entry, arch_entries, > > IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY); > > > > /* > > @@ -1005,7 +1003,8 @@ void ima_update_policy(struct ima_namespace *ns) > > * on boot. After loading a custom policy, free the > > * architecture specific rules stored as an array. > > */ > > - kfree(arch_policy_entry); > > + kfree(ns->arch_policy_entry); > > + ns->arch_policy_entry = NULL; > > So the thing that prevents multiple racing occurances of the above two lines is > that ima_open_policy() sets IMA_FS_BUSY (or returns EBUSY) and then removes > this file before clearing the flag, right? (To correct the above: ima_update_policy completes before the flag is cleared. The file is not removed in all cases but that's ok.) > Seems good. > > Reviewed-by: Serge Hallyn <serge@hallyn.com> > > > > } > > ima_update_policy_flags(ns); > > > > -- > > 2.34.1
On 5/20/22 22:46, Serge E. Hallyn wrote: > On Wed, Apr 20, 2022 at 10:06:11AM -0400, Stefan Berger wrote: >> @@ -1005,7 +1003,8 @@ void ima_update_policy(struct ima_namespace *ns) >> * on boot. After loading a custom policy, free the >> * architecture specific rules stored as an array. >> */ >> - kfree(arch_policy_entry); >> + kfree(ns->arch_policy_entry); >> + ns->arch_policy_entry = NULL; > > So the thing that prevents multiple racing occurances of the above two lines is > that ima_open_policy() sets IMA_FS_BUSY (or returns EBUSY) and then removes > this file before clearing the flag, right? Correct. > > Seems good. > > Reviewed-by: Serge Hallyn <serge@hallyn.com> > > >> } >> ima_update_policy_flags(ns); >> >> -- >> 2.34.1
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 9bcde1a24e74..2305bf223a98 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -125,6 +125,9 @@ struct ima_namespace { struct list_head __rcu *ima_rules; /* Pointer to the current policy */ int ima_policy_flag; + + /* An array of architecture specific rules */ + struct ima_rule_entry *arch_policy_entry; } __randomize_layout; extern struct ima_namespace init_ima_ns; diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c index c919a456b525..ae33621c3955 100644 --- a/security/integrity/ima/ima_init_ima_ns.c +++ b/security/integrity/ima/ima_init_ima_ns.c @@ -15,6 +15,7 @@ static int ima_init_namespace(struct ima_namespace *ns) INIT_LIST_HEAD(&ns->ima_temp_rules); ns->ima_rules = (struct list_head __rcu *)(&ns->ima_default_rules); ns->ima_policy_flag = 0; + ns->arch_policy_entry = NULL; return 0; } diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 69b19f4d5fee..0a7c61ca3265 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -228,9 +228,6 @@ static struct ima_rule_entry critical_data_rules[] __ro_after_init = { {.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC}, }; -/* An array of architecture specific rules */ -static struct ima_rule_entry *arch_policy_entry __ro_after_init; - static int ima_policy __initdata; static int __init default_measure_policy_setup(char *str) @@ -859,9 +856,10 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns) for (rules = arch_rules; *rules != NULL; rules++) arch_entries++; - arch_policy_entry = kcalloc(arch_entries + 1, - sizeof(*arch_policy_entry), GFP_KERNEL); - if (!arch_policy_entry) + ns->arch_policy_entry = kcalloc(arch_entries + 1, + sizeof(*ns->arch_policy_entry), + GFP_KERNEL); + if (!ns->arch_policy_entry) return 0; /* Convert each policy string rules to struct ima_rule_entry format */ @@ -871,13 +869,13 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns) result = strscpy(rule, *rules, sizeof(rule)); - INIT_LIST_HEAD(&arch_policy_entry[i].list); - result = ima_parse_rule(ns, rule, &arch_policy_entry[i]); + INIT_LIST_HEAD(&ns->arch_policy_entry[i].list); + result = ima_parse_rule(ns, rule, &ns->arch_policy_entry[i]); if (result) { pr_warn("Skipping unknown architecture policy rule: %s\n", rule); - memset(&arch_policy_entry[i], 0, - sizeof(*arch_policy_entry)); + memset(&ns->arch_policy_entry[i], 0, + sizeof(ns->arch_policy_entry[i])); continue; } i++; @@ -925,7 +923,7 @@ void __init ima_init_policy(struct ima_namespace *ns) if (!arch_entries) pr_info("No architecture policies found\n"); else - add_rules(ns, arch_policy_entry, arch_entries, + add_rules(ns, ns->arch_policy_entry, arch_entries, IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY); /* @@ -1005,7 +1003,8 @@ void ima_update_policy(struct ima_namespace *ns) * on boot. After loading a custom policy, free the * architecture specific rules stored as an array. */ - kfree(arch_policy_entry); + kfree(ns->arch_policy_entry); + ns->arch_policy_entry = NULL; } ima_update_policy_flags(ns);