From f2b85a4cc763841843de693bbd7308fe9a2c4c89 Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Wed, 28 Feb 2024 23:44:00 +0100 Subject: [PATCH] tls: fix use-after-free on failed backlog decryption commit 13114dc5543069f7b97991e3b79937b6da05f5b0 upstream. When the decrypt request goes to the backlog and crypto_aead_decrypt returns -EBUSY, tls_do_decryption will wait until all async decryptions have completed. If one of them fails, tls_do_decryption will return -EBADMSG and tls_decrypt_sg jumps to the error path, releasing all the pages. But the pages have been passed to the async callback, and have already been released by tls_decrypt_done. The only true async case is when crypto_aead_decrypt returns -EINPROGRESS. With -EBUSY, we already waited so we can tell tls_sw_recvmsg that the data is available for immediate copy, but we need to notify tls_decrypt_sg (via the new ->async_done flag) that the memory has already been released. Fixes: 859054147318 ("net: tls: handle backlogging of crypto requests") Signed-off-by: Sabrina Dubroca Link: https://lore.kernel.org/r/4755dd8d9bebdefaa19ce1439b833d6199d4364c.1709132643.git.sd@queasysnail.net Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/tls/tls_sw.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index e723584fc644..bdb5153f3788 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -51,6 +51,7 @@ struct tls_decrypt_arg { struct_group(inargs, bool zc; bool async; + bool async_done; u8 tail; ); @@ -279,18 +280,19 @@ static int tls_do_decryption(struct sock *sk, } ret = crypto_aead_decrypt(aead_req); + if (ret == -EINPROGRESS) + return 0; + if (ret == -EBUSY) { ret = tls_decrypt_async_wait(ctx); + darg->async_done = true; + /* all completions have run, we're not doing async anymore */ + darg->async = false; + return ret; ret = ret ?: -EINPROGRESS; } - if (ret == -EINPROGRESS) { - if (darg->async) - return 0; - ret = crypto_wait_req(ret, &ctx->async_wait); - } else if (darg->async) { - atomic_dec(&ctx->decrypt_pending); - } + atomic_dec(&ctx->decrypt_pending); darg->async = false; return ret; @@ -1681,8 +1683,11 @@ static int tls_decrypt_sg(struct sock *sk, struct iov_iter *out_iov, /* Prepare and submit AEAD request */ err = tls_do_decryption(sk, sgin, sgout, dctx->iv, data_len + prot->tail_size, aead_req, darg); - if (err) + if (err) { + if (darg->async_done) + goto exit_free_skb; goto exit_free_pages; + } darg->skb = clear_skb ?: tls_strp_msg(ctx); clear_skb = NULL; @@ -1694,6 +1699,9 @@ static int tls_decrypt_sg(struct sock *sk, struct iov_iter *out_iov, return err; } + if (unlikely(darg->async_done)) + return 0; + if (prot->tail_size) darg->tail = dctx->tail;