audit: always check the netlink payload length in audit_receive_msg()
This patch ensures that we always check the netlink payload length in audit_receive_msg() before we take any action on the payload itself. Cc: stable@vger.kernel.org Reported-by: syzbot+399c44bf1f43b8747403@syzkaller.appspotmail.com Reported-by: syzbot+e4b12d8d202701f08b6d@syzkaller.appspotmail.com Signed-off-by: Paul Moore <paul@paul-moore.com>
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@ -1101,13 +1101,11 @@ static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature
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audit_log_end(ab);
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}
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static int audit_set_feature(struct sk_buff *skb)
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static int audit_set_feature(struct audit_features *uaf)
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{
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struct audit_features *uaf;
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int i;
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BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
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uaf = nlmsg_data(nlmsg_hdr(skb));
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/* if there is ever a version 2 we should handle that here */
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@ -1175,6 +1173,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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{
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u32 seq;
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void *data;
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int data_len;
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int err;
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struct audit_buffer *ab;
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u16 msg_type = nlh->nlmsg_type;
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@ -1188,6 +1187,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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seq = nlh->nlmsg_seq;
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data = nlmsg_data(nlh);
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data_len = nlmsg_len(nlh);
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switch (msg_type) {
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case AUDIT_GET: {
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@ -1211,7 +1211,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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struct audit_status s;
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memset(&s, 0, sizeof(s));
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/* guard against past and future API changes */
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memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
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memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
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if (s.mask & AUDIT_STATUS_ENABLED) {
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err = audit_set_enabled(s.enabled);
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if (err < 0)
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@ -1315,7 +1315,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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return err;
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break;
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case AUDIT_SET_FEATURE:
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err = audit_set_feature(skb);
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if (data_len < sizeof(struct audit_features))
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return -EINVAL;
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err = audit_set_feature(data);
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if (err)
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return err;
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break;
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@ -1327,6 +1329,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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err = audit_filter(msg_type, AUDIT_FILTER_USER);
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if (err == 1) { /* match or error */
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char *str = data;
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err = 0;
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if (msg_type == AUDIT_USER_TTY) {
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err = tty_audit_push();
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@ -1334,26 +1338,24 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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break;
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}
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audit_log_user_recv_msg(&ab, msg_type);
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if (msg_type != AUDIT_USER_TTY)
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if (msg_type != AUDIT_USER_TTY) {
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/* ensure NULL termination */
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str[data_len - 1] = '\0';
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audit_log_format(ab, " msg='%.*s'",
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AUDIT_MESSAGE_TEXT_MAX,
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(char *)data);
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else {
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int size;
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str);
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} else {
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audit_log_format(ab, " data=");
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size = nlmsg_len(nlh);
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if (size > 0 &&
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((unsigned char *)data)[size - 1] == '\0')
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size--;
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audit_log_n_untrustedstring(ab, data, size);
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if (data_len > 0 && str[data_len - 1] == '\0')
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data_len--;
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audit_log_n_untrustedstring(ab, str, data_len);
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}
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audit_log_end(ab);
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}
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break;
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case AUDIT_ADD_RULE:
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case AUDIT_DEL_RULE:
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if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
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if (data_len < sizeof(struct audit_rule_data))
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return -EINVAL;
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if (audit_enabled == AUDIT_LOCKED) {
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audit_log_common_recv_msg(audit_context(), &ab,
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@ -1365,7 +1367,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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audit_log_end(ab);
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return -EPERM;
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}
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err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh));
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err = audit_rule_change(msg_type, seq, data, data_len);
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break;
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case AUDIT_LIST_RULES:
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err = audit_list_rules_send(skb, seq);
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@ -1380,7 +1382,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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case AUDIT_MAKE_EQUIV: {
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void *bufp = data;
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u32 sizes[2];
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size_t msglen = nlmsg_len(nlh);
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size_t msglen = data_len;
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char *old, *new;
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err = -EINVAL;
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@ -1456,7 +1458,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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memset(&s, 0, sizeof(s));
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/* guard against past and future API changes */
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memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
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memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
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/* check if new data is valid */
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if ((s.enabled != 0 && s.enabled != 1) ||
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(s.log_passwd != 0 && s.log_passwd != 1))
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