Patch "tls: adjust recv return with async crypto and failed copy to userspace" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    tls: adjust recv return with async crypto and failed copy to userspace

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tls-adjust-recv-return-with-async-crypto-and-failed-.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 84495576a9d8d0027e340123f307cb8a3bb70743
Author: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
Date:   Mon Mar 25 16:56:46 2024 +0100

    tls: adjust recv return with async crypto and failed copy to userspace
    
    [ Upstream commit 85eef9a41d019b59be7bc91793f26251909c0710 ]
    
    process_rx_list may not copy as many bytes as we want to the userspace
    buffer, for example in case we hit an EFAULT during the copy. If this
    happens, we should only count the bytes that were actually copied,
    which may be 0.
    
    Subtracting async_copy_bytes is correct in both peek and !peek cases,
    because decrypted == async_copy_bytes + peeked for the peek case: peek
    is always !ZC, and we can go through either the sync or async path. In
    the async case, we add chunk to both decrypted and
    async_copy_bytes. In the sync case, we add chunk to both decrypted and
    peeked. I missed that in commit 6caaf104423d ("tls: fix peeking with
    sync+async decryption").
    
    Fixes: 4d42cd6bc2ac ("tls: rx: fix return value for async crypto")
    Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
    Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/1b5a1eaab3c088a9dd5d9f1059ceecd7afe888d1.1711120964.git.sd@xxxxxxxxxxxxxxx
    Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 8e753d10e694a..925de4caa894a 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2158,6 +2158,9 @@ int tls_sw_recvmsg(struct sock *sk,
 		else
 			err = process_rx_list(ctx, msg, &control, 0,
 					      async_copy_bytes, is_peek, NULL);
+
+		/* we could have copied less than we wanted, and possibly nothing */
+		decrypted += max(err, 0) - async_copy_bytes;
 	}
 
 	copied += decrypted;