Patch "xen: Make struct privcmd_irqfd's layout architecture independent" 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

    xen: Make struct privcmd_irqfd's layout architecture independent

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:
     xen-make-struct-privcmd_irqfd-s-layout-architecture-.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 96c36db91ec56440ead2425281c12c6dcaffff2e
Author: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Date:   Mon Oct 16 12:41:24 2023 +0530

    xen: Make struct privcmd_irqfd's layout architecture independent
    
    [ Upstream commit 8dd765a5d769c521d73931850d1c8708fbc490cb ]
    
    Using indirect pointers in an ioctl command argument means that the
    layout is architecture specific, in particular we can't use the same one
    from 32-bit compat tasks. The general recommendation is to have __u64
    members and use u64_to_user_ptr() to access it from the kernel if we are
    unable to avoid the pointers altogether.
    
    Fixes: f8941e6c4c71 ("xen: privcmd: Add support for irqfd")
    Reported-by: Arnd Bergmann <arnd@xxxxxxxxxx>
    Closes: https://lore.kernel.org/all/268a2031-63b8-4c7d-b1e5-8ab83ca80b4a@xxxxxxxxxxxxxxxx/
    Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
    Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
    Link: https://lore.kernel.org/r/a4ef0d4a68fc858b34a81fd3f9877d9b6898eb77.1697439990.git.viresh.kumar@xxxxxxxxxx
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index f00ad5f5f1d4a..da88173bac432 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -935,7 +935,7 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd)
 		return -ENOMEM;
 	dm_op = kirqfd + 1;
 
-	if (copy_from_user(dm_op, irqfd->dm_op, irqfd->size)) {
+	if (copy_from_user(dm_op, u64_to_user_ptr(irqfd->dm_op), irqfd->size)) {
 		ret = -EFAULT;
 		goto error_kfree;
 	}
diff --git a/include/uapi/xen/privcmd.h b/include/uapi/xen/privcmd.h
index 375718ba4ab62..b143fafce84db 100644
--- a/include/uapi/xen/privcmd.h
+++ b/include/uapi/xen/privcmd.h
@@ -102,7 +102,7 @@ struct privcmd_mmap_resource {
 #define PRIVCMD_IRQFD_FLAG_DEASSIGN (1 << 0)
 
 struct privcmd_irqfd {
-	void __user *dm_op;
+	__u64 dm_op;
 	__u32 size; /* Size of structure pointed by dm_op */
 	__u32 fd;
 	__u32 flags;