net/tls: Fix flipped sign in tls_err_abort() calls

commit da353fac65fede6b8b4cfe207f0d9408e3121105 upstream.

sk->sk_err appears to expect a positive value, a convention that ktls
doesn't always follow and that leads to memory corruption in other code.
For instance,

    [kworker]
    tls_encrypt_done(..., err=<negative error from crypto request>)
      tls_err_abort(.., err)
        sk->sk_err = err;

    [task]
    splice_from_pipe_feed
      ...
        tls_sw_do_sendpage
          if (sk->sk_err) {
            ret = -sk->sk_err;  // ret is positive

    splice_from_pipe_feed (continued)
      ret = actor(...)  // ret is still positive and interpreted as bytes
                        // written, resulting in underflow of buf->len and
                        // sd->len, leading to huge buf->offset and bogus
                        // addresses computed in later calls to actor()

Fix all tls_err_abort() callers to pass a negative error code
consistently and centralize the error-prone sign flip there, throwing in
a warning to catch future misuse and uninlining the function so it
really does only warn once.

Cc: stable@vger.kernel.org
Fixes: 3ff4595c20b5a ("tls: RX path for ktls")
Reported-by: syzbot+b187b77c8474f9648fae@syzkaller.appspotmail.com
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/tls.h b/include/net/tls.h
index 697df45c0bceee3864ef441280a83dbb69dfe3ef..7f220e03ebb2daa442e0ebbdfec4cbd5f6182e6d 100644 (file)
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -360,6 +360,7 @@ int tls_sk_query(struct sock *sk, int optname, char __user *optval,
                int __user *optlen);
 int tls_sk_attach(struct sock *sk, int optname, char __user *optval,
                  unsigned int optlen);
+void tls_err_abort(struct sock *sk, int err);
 
 int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx);
 void tls_sw_strparser_arm(struct sock *sk, struct tls_context *ctx);
@@ -465,12 +466,6 @@ static inline bool tls_is_sk_tx_device_offloaded(struct sock *sk)
 #endif
 }
 
-static inline void tls_err_abort(struct sock *sk, int err)
-{
-       sk->sk_err = err;
-       sk->sk_error_report(sk);
-}
-
 static inline bool tls_bigint_increment(unsigned char *seq, int len)
 {
        int i;
@@ -499,7 +494,7 @@ static inline void tls_advance_record_sn(struct sock *sk,
                                         struct cipher_context *ctx)
 {
        if (tls_bigint_increment(ctx->rec_seq, prot->rec_seq_size))
-               tls_err_abort(sk, EBADMSG);
+               tls_err_abort(sk, -EBADMSG);
 
        if (prot->version != TLS_1_3_VERSION)
                tls_bigint_increment(ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 7fb5c067f429373ddd39ec76e3fec9856ad9d370..8c9d2055d92b0f0aae838e59c0ebbcf7d0c45649 100644 (file)
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -35,6 +35,7 @@
  * SOFTWARE.
  */
 
+#include <linux/bug.h>
 #include <linux/sched/signal.h>
 #include <linux/module.h>
 #include <linux/splice.h>
@@ -43,6 +44,14 @@
 #include <net/strparser.h>
 #include <net/tls.h>
 
+noinline void tls_err_abort(struct sock *sk, int err)
+{
+       WARN_ON_ONCE(err >= 0);
+       /* sk->sk_err should contain a positive error code. */
+       sk->sk_err = -err;
+       sk->sk_error_report(sk);
+}
+
 static int __skb_nsg(struct sk_buff *skb, int offset, int len,
                      unsigned int recursion_level)
 {
@@ -416,7 +425,7 @@ int tls_tx_records(struct sock *sk, int flags)
 
 tx_err:
        if (rc < 0 && rc != -EAGAIN)
-               tls_err_abort(sk, EBADMSG);
+               tls_err_abort(sk, -EBADMSG);
 
        return rc;
 }
@@ -761,7 +770,7 @@ static int tls_push_record(struct sock *sk, int flags,
                               msg_pl->sg.size + prot->tail_size, i);
        if (rc < 0) {
                if (rc != -EINPROGRESS) {
-                       tls_err_abort(sk, EBADMSG);
+                       tls_err_abort(sk, -EBADMSG);
                        if (split) {
                                tls_ctx->pending_open_record_frags = true;
                                tls_merge_open_record(sk, rec, tmp, orig_end);
@@ -1822,7 +1831,7 @@ int tls_sw_recvmsg(struct sock *sk,
                err = decrypt_skb_update(sk, skb, &msg->msg_iter,
                                         &chunk, &zc, async_capable);
                if (err < 0 && err != -EINPROGRESS) {
-                       tls_err_abort(sk, EBADMSG);
+                       tls_err_abort(sk, -EBADMSG);
                        goto recv_end;
                }
 
@@ -2002,7 +2011,7 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
                }
 
                if (err < 0) {
-                       tls_err_abort(sk, EBADMSG);
+                       tls_err_abort(sk, -EBADMSG);
                        goto splice_read_end;
                }
                ctx->decrypted = true;