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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: Li Li <dualli@chromium.org>
Link: https://lore.kernel.org/CANBPYPjQVqmzZ4J=rVQX87a9iuwmaetULwbK_5_3YWk2eGzkaA@mail.gmail.com
Fixes: 170aafe35c ("netdev: support binding dma-buf to netdevice")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Link: https://patch.msgid.link/20250115161436.648646-1-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Jakub Kicinski 2025-01-15 08:14:36 -08:00 committed by Paolo Abeni
parent 676d53a480
commit a50da36562
2 changed files with 25 additions and 5 deletions

View file

@ -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,
};

View file

@ -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(';')