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authorJohn Johansen <john.johansen@canonical.com>2017-06-10 00:38:35 +0300
committerJohn Johansen <john.johansen@canonical.com>2017-06-11 03:11:42 +0300
commit290f458a4f16f9cf6cb6562b249e69fe1c3c3a07 (patch)
tree41b1a79cb019d8fbbb1b07c28e5d926656728ccd /security
parentb2d09ae449cedc6f276ac485c013d22a97d36992 (diff)
downloadlinux-290f458a4f16f9cf6cb6562b249e69fe1c3c3a07.tar.xz
apparmor: allow ptrace checks to be finer grained than just capability
Signed-off-by: John Johansen <john.johansen@canonical.com>
Diffstat (limited to 'security')
-rw-r--r--security/apparmor/apparmorfs.c6
-rw-r--r--security/apparmor/include/ipc.h6
-rw-r--r--security/apparmor/ipc.c56
3 files changed, 68 insertions, 0 deletions
diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index d24100f8fd98..d1a6ce499776 100644
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -2086,6 +2086,11 @@ static struct aa_sfs_entry aa_sfs_entry_file[] = {
{ }
};
+static struct aa_sfs_entry aa_sfs_entry_ptrace[] = {
+ AA_SFS_FILE_STRING("mask", "read trace"),
+ { }
+};
+
static struct aa_sfs_entry aa_sfs_entry_domain[] = {
AA_SFS_FILE_BOOLEAN("change_hat", 1),
AA_SFS_FILE_BOOLEAN("change_hatv", 1),
@@ -2125,6 +2130,7 @@ static struct aa_sfs_entry aa_sfs_entry_features[] = {
AA_SFS_FILE_U64("capability", VFS_CAP_FLAGS_MASK),
AA_SFS_DIR("rlimit", aa_sfs_entry_rlimit),
AA_SFS_DIR("caps", aa_sfs_entry_caps),
+ AA_SFS_DIR("ptrace", aa_sfs_entry_ptrace),
AA_SFS_DIR("query", aa_sfs_entry_query),
{ }
};
diff --git a/security/apparmor/include/ipc.h b/security/apparmor/include/ipc.h
index fb3e751e6eed..656fdb81c8a0 100644
--- a/security/apparmor/include/ipc.h
+++ b/security/apparmor/include/ipc.h
@@ -21,6 +21,12 @@ struct aa_profile;
#define AA_PTRACE_TRACE MAY_WRITE
#define AA_PTRACE_READ MAY_READ
+#define AA_MAY_BE_TRACED AA_MAY_APPEND
+#define AA_MAY_BE_READ AA_MAY_CREATE
+#define PTRACE_PERM_SHIFT 2
+
+#define AA_PTRACE_PERM_MASK (AA_PTRACE_READ | AA_PTRACE_TRACE | \
+ AA_MAY_BE_READ | AA_MAY_BE_TRACED)
int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee,
u32 request);
diff --git a/security/apparmor/ipc.c b/security/apparmor/ipc.c
index f81649369f05..11e66b5bbc42 100644
--- a/security/apparmor/ipc.c
+++ b/security/apparmor/ipc.c
@@ -21,20 +21,76 @@
#include "include/policy.h"
#include "include/ipc.h"
+/**
+ * audit_ptrace_mask - convert mask to permission string
+ * @buffer: buffer to write string to (NOT NULL)
+ * @mask: permission mask to convert
+ */
+static void audit_ptrace_mask(struct audit_buffer *ab, u32 mask)
+{
+ switch (mask) {
+ case MAY_READ:
+ audit_log_string(ab, "read");
+ break;
+ case MAY_WRITE:
+ audit_log_string(ab, "trace");
+ break;
+ case AA_MAY_BE_READ:
+ audit_log_string(ab, "readby");
+ break;
+ case AA_MAY_BE_TRACED:
+ audit_log_string(ab, "tracedby");
+ break;
+ }
+}
+
/* call back to audit ptrace fields */
static void audit_ptrace_cb(struct audit_buffer *ab, void *va)
{
struct common_audit_data *sa = va;
+ if (aad(sa)->request & AA_PTRACE_PERM_MASK) {
+ audit_log_format(ab, " requested_mask=");
+ audit_ptrace_mask(ab, aad(sa)->request);
+
+ if (aad(sa)->denied & AA_PTRACE_PERM_MASK) {
+ audit_log_format(ab, " denied_mask=");
+ audit_ptrace_mask(ab, aad(sa)->denied);
+ }
+ }
audit_log_format(ab, " peer=");
aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
FLAGS_NONE, GFP_ATOMIC);
}
+/* TODO: conditionals */
+static int profile_ptrace_perm(struct aa_profile *profile,
+ struct aa_profile *peer, u32 request,
+ struct common_audit_data *sa)
+{
+ struct aa_perms perms = { };
+
+ /* need because of peer in cross check */
+ if (profile_unconfined(profile) ||
+ !PROFILE_MEDIATES(profile, AA_CLASS_PTRACE))
+ return 0;
+
+ aad(sa)->peer = &peer->label;
+ aa_profile_match_label(profile, &peer->label, AA_CLASS_PTRACE, request,
+ &perms);
+ aa_apply_modes_to_perms(profile, &perms);
+ return aa_check_perms(profile, &perms, request, sa, audit_ptrace_cb);
+}
+
static int cross_ptrace_perm(struct aa_profile *tracer,
struct aa_profile *tracee, u32 request,
struct common_audit_data *sa)
{
+ if (PROFILE_MEDIATES(tracer, AA_CLASS_PTRACE))
+ return xcheck(profile_ptrace_perm(tracer, tracee, request, sa),
+ profile_ptrace_perm(tracee, tracer,
+ request << PTRACE_PERM_SHIFT,
+ sa));
/* policy uses the old style capability check for ptrace */
if (profile_unconfined(tracer) || tracer == tracee)
return 0;