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apparmor: move ptrace checks to using labels 

Signed-off-by: John Johansen <john.johansen@canonical.com>
hifive-unleashed-5.1
John Johansen 2017-06-09 14:22:14 -07:00
parent ca916e8e2d
commit b2d09ae449
5 changed files with 58 additions and 80 deletions
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17
security/apparmor/domain.c
View File

@ -51,14 +51,16 @@ void aa_free_domain_entries(struct aa_domain *domain)
/**
* may_change_ptraced_domain - check if can change profile on ptraced task
* @to_profile: profile to change to (NOT NULL)
* @to_label: profile to change to (NOT NULL)
* @info: message if there is an error
*
* Check if current is ptraced and if so if the tracing task is allowed
* to trace the new domain
*
* Returns: %0 or error if change not allowed
*/
static int may_change_ptraced_domain(struct aa_profile *to_profile)
static int may_change_ptraced_domain(struct aa_label *to_label,
const char **info)
{
struct task_struct *tracer;
struct aa_label *tracerl = NULL;
@ -74,13 +76,14 @@ static int may_change_ptraced_domain(struct aa_profile *to_profile)
if (!tracer || unconfined(tracerl))
goto out;
error = aa_may_ptrace(labels_profile(tracerl), to_profile,
PTRACE_MODE_ATTACH);
error = aa_may_ptrace(tracerl, to_label, PTRACE_MODE_ATTACH);
out:
rcu_read_unlock();
aa_put_label(tracerl);
if (error)
*info = "ptrace prevents transition";
return error;
}
@ -477,7 +480,7 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
}
if (bprm->unsafe & LSM_UNSAFE_PTRACE) {
error = may_change_ptraced_domain(new_profile);
error = may_change_ptraced_domain(&new_profile->label, &info);
if (error)
goto audit;
}
@ -661,7 +664,7 @@ int aa_change_hat(const char *hats[], int count, u64 token, int flags)
}
}
error = may_change_ptraced_domain(hat);
error = may_change_ptraced_domain(&hat->label, &info);
if (error) {
info = "ptraced";
error = -EPERM;
@ -782,7 +785,7 @@ int aa_change_profile(const char *fqname, int flags)
}
/* check if tracing task is allowed to trace target domain */
error = may_change_ptraced_domain(target);
error = may_change_ptraced_domain(&target->label, &info);
if (error) {
info = "ptrace prevents transition";
goto audit;

1
security/apparmor/include/apparmor.h
View File

@ -27,6 +27,7 @@
#define AA_CLASS_NET 4
#define AA_CLASS_RLIMITS 5
#define AA_CLASS_DOMAIN 6
#define AA_CLASS_PTRACE 9
#define AA_CLASS_LABEL 16
#define AA_CLASS_LAST AA_CLASS_LABEL

10
security/apparmor/include/ipc.h
View File

@ -4,7 +4,7 @@
* This file contains AppArmor ipc mediation function definitions.
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
* Copyright 2009-2017 Canonical Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
@ -19,10 +19,10 @@
struct aa_profile;
int aa_may_ptrace(struct aa_profile *tracer, struct aa_profile *tracee,
unsigned int mode);
#define AA_PTRACE_TRACE MAY_WRITE
#define AA_PTRACE_READ MAY_READ
int aa_ptrace(struct task_struct *tracer, struct task_struct *tracee,
unsigned int mode);
int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee,
u32 request);
#endif /* __AA_IPC_H */

87
security/apparmor/ipc.c
View File

@ -4,7 +4,7 @@
* This file contains AppArmor ipc mediation
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
* Copyright 2009-2017 Canonical Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
@ -25,88 +25,43 @@
static void audit_ptrace_cb(struct audit_buffer *ab, void *va)
{
struct common_audit_data *sa = va;
audit_log_format(ab, " peer=");
aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
FLAGS_NONE, GFP_ATOMIC);
}
/**
* aa_audit_ptrace - do auditing for ptrace
* @profile: profile being enforced (NOT NULL)
* @target: profile being traced (NOT NULL)
* @error: error condition
*
* Returns: %0 or error code
*/
static int aa_audit_ptrace(struct aa_profile *profile,
struct aa_profile *target, int error)
static int cross_ptrace_perm(struct aa_profile *tracer,
struct aa_profile *tracee, u32 request,
struct common_audit_data *sa)
{
DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_PTRACE);
/* policy uses the old style capability check for ptrace */
if (profile_unconfined(tracer) || tracer == tracee)
return 0;
aad(&sa)->peer = &target->label;
aad(&sa)->error = error;
aad(sa)->label = &tracer->label;
aad(sa)->peer = &tracee->label;
aad(sa)->request = 0;
aad(sa)->error = aa_capable(&tracer->label, CAP_SYS_PTRACE, 1);
return aa_audit(AUDIT_APPARMOR_AUTO, profile, &sa, audit_ptrace_cb);
return aa_audit(AUDIT_APPARMOR_AUTO, tracer, sa, audit_ptrace_cb);
}
/**
* aa_may_ptrace - test if tracer task can trace the tracee
* @tracer: profile of the task doing the tracing (NOT NULL)
* @tracee: task to be traced
* @mode: whether PTRACE_MODE_READ || PTRACE_MODE_ATTACH
* @tracer: label of the task doing the tracing (NOT NULL)
* @tracee: task label to be traced
* @request: permission request
*
* Returns: %0 else error code if permission denied or error
*/
int aa_may_ptrace(struct aa_profile *tracer, struct aa_profile *tracee,
unsigned int mode)
int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee,
u32 request)
{
/* TODO: currently only based on capability, not extended ptrace
* rules,
* Test mode for PTRACE_MODE_READ || PTRACE_MODE_ATTACH
*/
DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_PTRACE);
if (profile_unconfined(tracer) || tracer == tracee)
return 0;
/* log this capability request */
return aa_capable(&tracer->label, CAP_SYS_PTRACE, 1);
return xcheck_labels_profiles(tracer, tracee, cross_ptrace_perm,
request, &sa);
}
/**
* aa_ptrace - do ptrace permission check and auditing
* @tracer: task doing the tracing (NOT NULL)
* @tracee: task being traced (NOT NULL)
* @mode: ptrace mode either PTRACE_MODE_READ || PTRACE_MODE_ATTACH
*
* Returns: %0 else error code if permission denied or error
*/
int aa_ptrace(struct task_struct *tracer, struct task_struct *tracee,
unsigned int mode)
{
/*
* tracer can ptrace tracee when
* - tracer is unconfined ||
* - tracer is in complain mode
* - tracer has rules allowing it to trace tracee currently this is:
* - confined by the same profile ||
* - tracer profile has CAP_SYS_PTRACE
*/
struct aa_label *tracer_l = aa_get_task_label(tracer);
int error = 0;
if (!unconfined(tracer_l)) {
struct aa_label *tracee_l = aa_get_task_label(tracee);
error = aa_may_ptrace(labels_profile(tracer_l),
labels_profile(tracee_l),
mode);
error = aa_audit_ptrace(labels_profile(tracer_l),
labels_profile(tracee_l),
error);
aa_put_label(tracee_l);
}
aa_put_label(tracer_l);
return error;
}

23
security/apparmor/lsm.c
View File

@ -104,12 +104,31 @@ static void apparmor_cred_transfer(struct cred *new, const struct cred *old)
static int apparmor_ptrace_access_check(struct task_struct *child,
unsigned int mode)
{
return aa_ptrace(current, child, mode);
struct aa_label *tracer, *tracee;
int error;
tracer = begin_current_label_crit_section();
tracee = aa_get_task_label(child);
error = aa_may_ptrace(tracer, tracee,
mode == PTRACE_MODE_READ ? AA_PTRACE_READ : AA_PTRACE_TRACE);
aa_put_label(tracee);
end_current_label_crit_section(tracer);
return error;
}
static int apparmor_ptrace_traceme(struct task_struct *parent)
{
return aa_ptrace(parent, current, PTRACE_MODE_ATTACH);
struct aa_label *tracer, *tracee;
int error;
tracee = begin_current_label_crit_section();
tracer = aa_get_task_label(parent);
error = aa_may_ptrace(tracer, tracee, AA_PTRACE_TRACE);
aa_put_label(tracer);
end_current_label_crit_section(tracee);
return error;
}
/* Derived from security/commoncap.c:cap_capget */