Patch "io_uring/net: fix overflow check in io_recvmsg_mshot_prep()" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    io_uring/net: fix overflow check in io_recvmsg_mshot_prep()

to the 6.1-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:
     io_uring-net-fix-overflow-check-in-io_recvmsg_mshot_.patch
and it can be found in the queue-6.1 subdirectory.

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



commit 466427d64e77b919436cf3dbef3c44069d814aa0
Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Date:   Fri Mar 1 18:29:39 2024 +0300

    io_uring/net: fix overflow check in io_recvmsg_mshot_prep()
    
    [ Upstream commit 8ede3db5061bb1fe28e2c9683329aafa89d2b1b4 ]
    
    The "controllen" variable is type size_t (unsigned long).  Casting it
    to int could lead to an integer underflow.
    
    The check_add_overflow() function considers the type of the destination
    which is type int.  If we add two positive values and the result cannot
    fit in an integer then that's counted as an overflow.
    
    However, if we cast "controllen" to an int and it turns negative, then
    negative values *can* fit into an int type so there is no overflow.
    
    Good: 100 + (unsigned long)-4 = 96  <-- overflow
     Bad: 100 + (int)-4 = 96 <-- no overflow
    
    I deleted the cast of the sizeof() as well.  That's not a bug but the
    cast is unnecessary.
    
    Fixes: 9b0fc3c054ff ("io_uring: fix types in io_recvmsg_multishot_overflow")
    Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/138bd2e2-ede8-4bcc-aa7b-f3d9de167a37@moroto.mountain
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/io_uring/net.c b/io_uring/net.c
index b273914ed99f0..9fc0ffb0b6c12 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -524,10 +524,10 @@ static int io_recvmsg_mshot_prep(struct io_kiocb *req,
 
 		if (unlikely(namelen < 0))
 			return -EOVERFLOW;
-		if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
+		if (check_add_overflow(sizeof(struct io_uring_recvmsg_out),
 					namelen, &hdr))
 			return -EOVERFLOW;
-		if (check_add_overflow(hdr, (int)controllen, &hdr))
+		if (check_add_overflow(hdr, controllen, &hdr))
 			return -EOVERFLOW;
 
 		iomsg->namelen = namelen;