Commit a50da365 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Paolo Abeni
Browse files

netdev: avoid CFI problems with sock priv helpers 



Li Li reports that casting away callback type may cause issues
for CFI. Let's generate a small wrapper for each callback,
to make sure compiler sees the anticipated types.

Reported-by: default avatarLi Li <dualli@chromium.org>
Link: https://lore.kernel.org/CANBPYPjQVqmzZ4J=rVQX87a9iuwmaetULwbK_5_3YWk2eGzkaA@mail.gmail.com


Fixes: 170aafe3 ("netdev: support binding dma-buf to netdevice")
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarMina Almasry <almasrymina@google.com>
Link: https://patch.msgid.link/20250115161436.648646-1-kuba@kernel.org


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 676d53a4

net/core/netdev-genl-gen.c

+12 −2
Original line number Diff line number Diff line
@@ -197,6 +197,16 @@ static const struct genl_multicast_group netdev_nl_mcgrps[] = { 
	[NETDEV_NLGRP_PAGE_POOL] = { "page-pool", },

};



static void __netdev_nl_sock_priv_init(void *priv)

{

	netdev_nl_sock_priv_init(priv);

}



static void __netdev_nl_sock_priv_destroy(void *priv)

{

	netdev_nl_sock_priv_destroy(priv);

}



struct genl_family netdev_nl_family __ro_after_init = {

	.name		= NETDEV_FAMILY_NAME,

	.version	= NETDEV_FAMILY_VERSION,
@@ -208,6 +218,6 @@ struct genl_family netdev_nl_family __ro_after_init = { 
	.mcgrps		= netdev_nl_mcgrps,

	.n_mcgrps	= ARRAY_SIZE(netdev_nl_mcgrps),

	.sock_priv_size	= sizeof(struct list_head),

	.sock_priv_init	= (void *)netdev_nl_sock_priv_init,

	.sock_priv_destroy = (void *)netdev_nl_sock_priv_destroy,

	.sock_priv_init	= __netdev_nl_sock_priv_init,

	.sock_priv_destroy = __netdev_nl_sock_priv_destroy,

};

tools/net/ynl/ynl-gen-c.py

+13 −3
Original line number Diff line number Diff line
@@ -2384,6 +2384,17 @@ def print_kernel_family_struct_src(family, cw): 
    if not kernel_can_gen_family_struct(family):

        return



    if 'sock-priv' in family.kernel_family:

        # Generate "trampolines" to make CFI happy

        cw.write_func("static void", f"__{family.c_name}_nl_sock_priv_init",

                      [f"{family.c_name}_nl_sock_priv_init(priv);"],

                      ["void *priv"])

        cw.nl()

        cw.write_func("static void", f"__{family.c_name}_nl_sock_priv_destroy",

                      [f"{family.c_name}_nl_sock_priv_destroy(priv);"],

                      ["void *priv"])

        cw.nl()



    cw.block_start(f"struct genl_family {family.ident_name}_nl_family __ro_after_init =")

    cw.p('.name\t\t= ' + family.fam_key + ',')

    cw.p('.version\t= ' + family.ver_key + ',')
@@ -2401,9 +2412,8 @@ def print_kernel_family_struct_src(family, cw): 
        cw.p(f'.n_mcgrps\t= ARRAY_SIZE({family.c_name}_nl_mcgrps),')

    if 'sock-priv' in family.kernel_family:

        cw.p(f'.sock_priv_size\t= sizeof({family.kernel_family["sock-priv"]}),')

        # Force cast here, actual helpers take pointer to the real type.

        cw.p(f'.sock_priv_init\t= (void *){family.c_name}_nl_sock_priv_init,')

        cw.p(f'.sock_priv_destroy = (void *){family.c_name}_nl_sock_priv_destroy,')

        cw.p(f'.sock_priv_init\t= __{family.c_name}_nl_sock_priv_init,')

        cw.p(f'.sock_priv_destroy = __{family.c_name}_nl_sock_priv_destroy,')

    cw.block_end(';')