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

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: c46234ebb4 ("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>
This commit is contained in:
Daniel Jordan 2021-10-27 17:59:20 -04:00 committed by David S. Miller
parent a32f07d211
commit da353fac65
2 changed files with 15 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
include/net/tls.h
View File

@ -358,6 +358,7 @@ 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);
@ -466,12 +467,6 @@ 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_error_report(sk);
}
static inline bool tls_bigint_increment(unsigned char *seq, int len)
{
int i;
@ -512,7 +507,7 @@ 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 &&
prot->cipher_type != TLS_CIPHER_CHACHA20_POLY1305)

17
net/tls/tls_sw.c
View File

@ -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_error_report(sk);
}
static int __skb_nsg(struct sk_buff *skb, int offset, int len,
unsigned int recursion_level)
{
@ -419,7 +428,7 @@ 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;
}
@ -763,7 +772,7 @@ 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);
@ -1827,7 +1836,7 @@ 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;
}
@ -2007,7 +2016,7 @@ 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 = 1;