Zephaniah E. Loss-Cutler-Hull wrote:
This seems rather reproducible.
It seems to me that audit_signal_cb() is reading a pointer value rather than
signal number, for the address of aad(sa)->peer and aad(&sa)->signal are the
same due to use of "union" inside "struct apparmor_audit_data".
Thus, I think that this is an AppArmor side problem.
struct apparmor_audit_data {
int error;
int type;
const char *op;
struct aa_label *label;
const char *name;
const char *info;
u32 request;
u32 denied;
union {
/* these entries require a custom callback fn */
struct {
struct aa_label *peer;
struct {
const char *target;
kuid_t ouid;
} fs;
};
struct {
struct aa_profile *profile;
const char *ns;
long pos;
} iface;
int signal;
struct {
int rlim;
unsigned long max;
} rlim;
struct {
const char *src_name;
const char *type;
const char *trans;
const char *data;
unsigned long flags;
} mnt;
};
};
static int profile_signal_perm(struct aa_profile *profile,
struct aa_profile *peer, u32 request,
struct common_audit_data *sa)
{
struct aa_perms perms;
if (profile_unconfined(profile) ||
!PROFILE_MEDIATES(profile, AA_CLASS_SIGNAL))
return 0;
aad(sa)->peer = &peer->label; // Overwrites aad(sa)->signal value.
profile_match_signal(profile, peer->base.hname, aad(sa)->signal,
&perms);
aa_apply_modes_to_perms(profile, &perms);
return aa_check_perms(profile, &perms, request, sa, audit_signal_cb); // Oops
}
static int aa_signal_cross_perm(struct aa_profile *sender,
struct aa_profile *target,
struct common_audit_data *sa)
{
return xcheck(profile_signal_perm(sender, target, MAY_WRITE, sa),
profile_signal_perm(target, sender, MAY_READ, sa));
}
int aa_may_signal(struct aa_label *sender, struct aa_label *target, int sig)
{
DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SIGNAL);
aad(&sa)->signal = map_signal_num(sig); // Writes aad(sa)->signal
value.
return xcheck_labels_profiles(sender, target, aa_signal_cross_perm,
&sa);
}