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[AUDIT] clean up audit_receive_msg()
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generally clean up audit_receive_msg() don't free random memory if
selinux_sid_to_string fails for some reason.  Move generic auditing
to a helper function

Signed-off-by: Eric Paris <eparis@redhat.com>
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Eric Paris authored and Al Viro committed Feb 1, 2008
1 parent 1a6b9f2 commit 50397bd
Showing 1 changed file with 66 additions and 103 deletions.
169 changes: 66 additions & 103 deletions kernel/audit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -152,8 +152,10 @@ struct audit_buffer {

static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
{
struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
nlh->nlmsg_pid = pid;
if (ab) {
struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
nlh->nlmsg_pid = pid;
}
}

void audit_panic(const char *message)
Expand Down Expand Up @@ -511,6 +513,33 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
return err;
}

static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type,
u32 pid, u32 uid, uid_t auid, u32 sid)
{
int rc = 0;
char *ctx = NULL;
u32 len;

if (!audit_enabled) {
*ab = NULL;
return rc;
}

*ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
audit_log_format(*ab, "user pid=%d uid=%u auid=%u",
pid, uid, auid);
if (sid) {
rc = selinux_sid_to_string(sid, &ctx, &len);
if (rc)
audit_log_format(*ab, " ssid=%u", sid);
else
audit_log_format(*ab, " subj=%s", ctx);
kfree(ctx);
}

return rc;
}

static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
u32 uid, pid, seq, sid;
Expand All @@ -521,7 +550,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
u16 msg_type = nlh->nlmsg_type;
uid_t loginuid; /* loginuid of sender */
struct audit_sig_info *sig_data;
char *ctx;
char *ctx = NULL;
u32 len;

err = audit_netlink_ok(skb, msg_type);
Expand Down Expand Up @@ -602,64 +631,35 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
if (err)
break;
}
ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
if (ab) {
audit_log_format(ab,
"user pid=%d uid=%u auid=%u",
pid, uid, loginuid);
if (sid) {
if (selinux_sid_to_string(
sid, &ctx, &len)) {
audit_log_format(ab,
" ssid=%u", sid);
/* Maybe call audit_panic? */
} else
audit_log_format(ab,
" subj=%s", ctx);
kfree(ctx);
}
if (msg_type != AUDIT_USER_TTY)
audit_log_format(ab, " msg='%.1024s'",
(char *)data);
else {
int size;

audit_log_format(ab, " msg=");
size = nlmsg_len(nlh);
audit_log_n_untrustedstring(ab, size,
data);
}
audit_set_pid(ab, pid);
audit_log_end(ab);
audit_log_common_recv_msg(&ab, msg_type, pid, uid,
loginuid, sid);

if (msg_type != AUDIT_USER_TTY)
audit_log_format(ab, " msg='%.1024s'",
(char *)data);
else {
int size;

audit_log_format(ab, " msg=");
size = nlmsg_len(nlh);
audit_log_n_untrustedstring(ab, size,
data);
}
audit_set_pid(ab, pid);
audit_log_end(ab);
}
break;
case AUDIT_ADD:
case AUDIT_DEL:
if (nlmsg_len(nlh) < sizeof(struct audit_rule))
return -EINVAL;
if (audit_enabled == AUDIT_LOCKED) {
ab = audit_log_start(NULL, GFP_KERNEL,
AUDIT_CONFIG_CHANGE);
if (ab) {
audit_log_format(ab,
"pid=%d uid=%u auid=%u",
pid, uid, loginuid);
if (sid) {
if (selinux_sid_to_string(
sid, &ctx, &len)) {
audit_log_format(ab,
" ssid=%u", sid);
/* Maybe call audit_panic? */
} else
audit_log_format(ab,
" subj=%s", ctx);
kfree(ctx);
}
audit_log_format(ab, " audit_enabled=%d res=0",
audit_enabled);
audit_log_end(ab);
}
audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
uid, loginuid, sid);

audit_log_format(ab, " audit_enabled=%d res=0",
audit_enabled);
audit_log_end(ab);
return -EPERM;
}
/* fallthrough */
Expand All @@ -673,27 +673,12 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
return -EINVAL;
if (audit_enabled == AUDIT_LOCKED) {
ab = audit_log_start(NULL, GFP_KERNEL,
AUDIT_CONFIG_CHANGE);
if (ab) {
audit_log_format(ab,
"pid=%d uid=%u auid=%u",
pid, uid, loginuid);
if (sid) {
if (selinux_sid_to_string(
sid, &ctx, &len)) {
audit_log_format(ab,
" ssid=%u", sid);
/* Maybe call audit_panic? */
} else
audit_log_format(ab,
" subj=%s", ctx);
kfree(ctx);
}
audit_log_format(ab, " audit_enabled=%d res=0",
audit_enabled);
audit_log_end(ab);
}
audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
uid, loginuid, sid);

audit_log_format(ab, " audit_enabled=%d res=0",
audit_enabled);
audit_log_end(ab);
return -EPERM;
}
/* fallthrough */
Expand All @@ -704,19 +689,10 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
break;
case AUDIT_TRIM:
audit_trim_trees();
ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
if (!ab)
break;
audit_log_format(ab, "auid=%u", loginuid);
if (sid) {
u32 len;
ctx = NULL;
if (selinux_sid_to_string(sid, &ctx, &len))
audit_log_format(ab, " ssid=%u", sid);
else
audit_log_format(ab, " subj=%s", ctx);
kfree(ctx);
}

audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
uid, loginuid, sid);

audit_log_format(ab, " op=trim res=1");
audit_log_end(ab);
break;
Expand Down Expand Up @@ -746,22 +722,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
/* OK, here comes... */
err = audit_tag_tree(old, new);

ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
if (!ab) {
kfree(old);
kfree(new);
break;
}
audit_log_format(ab, "auid=%u", loginuid);
if (sid) {
u32 len;
ctx = NULL;
if (selinux_sid_to_string(sid, &ctx, &len))
audit_log_format(ab, " ssid=%u", sid);
else
audit_log_format(ab, " subj=%s", ctx);
kfree(ctx);
}
audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
uid, loginuid, sid);

audit_log_format(ab, " op=make_equiv old=");
audit_log_untrustedstring(ab, old);
audit_log_format(ab, " new=");
Expand Down

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