From: Masahiro Matsuya Date: Wed, 24 Aug 2022 17:36:37 +0000 (-0400) Subject: net/drivers/ieee1275/ofnet: Fix incorrect netmask X-Git-Tag: grub-2.12-rc1~268 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2c1425b8f00fb4b46ae5fcdd1553d1ccf2e4a987;p=thirdparty%2Fgrub.git net/drivers/ieee1275/ofnet: Fix incorrect netmask The netmask configured in firmware is not respected on ppc64 (big endian). When 255.255.252.0 is set as netmask in firmware, the following is the value of bootpath string in grub_ieee1275_parse_bootpath(): /vdevice/l-lan@30000002:speed=auto,duplex=auto,192.168.88.10,,192.168.89.113,192.168.88.1,5,5,255.255.252.0,512 The netmask in this bootpath is not a problem, since it's a value specified in firmware. But the value of subnet_mask.ipv4 was set with 0xfffffc00, and __builtin_ctz(~grub_le_to_cpu32(subnet_mask.ipv4)) returned 16 (not 22). As a result, 16 was used for netmask wrongly: 1111 1111 1111 1111 1111 1100 0000 0000 # subnet_mask.ipv4(=0xfffffc00) 0000 0000 1111 1100 1111 1111 1111 1111 # grub_le_to_cpu32(subnet_mask.ipv4) 1111 1111 0000 0011 0000 0000 0000 0000 # ~grub_le_to_cpu32(subnet_mask.ipv4) and the count of zero with __builtin_ctz() can be 16. This patch changes it as below: 1111 1111 1111 1111 1111 1100 0000 0000 # subnet_mask.ipv4(=0xfffffc00) 0000 0000 1111 1100 1111 1111 1111 1111 # grub_le_to_cpu32(subnet_mask.ipv4) 1111 1111 1111 1111 1111 1100 0000 0000 # grub_be_to_cpu32(subnet_mask.ipv4) 0000 0000 0000 0000 0000 0011 1111 1111 # ~grub_be_to_cpu32(subnet_mask.ipv4) The count of zero with __builtin_clz() can be 22 (clz counts the number of one bits preceding the most significant zero bit). Signed-off-by: Masahiro Matsuya Signed-off-by: Robbie Harwood Reviewed-by: Daniel Kiper --- diff --git a/grub-core/net/drivers/ieee1275/ofnet.c b/grub-core/net/drivers/ieee1275/ofnet.c index 8c8398948..78f03df8e 100644 --- a/grub-core/net/drivers/ieee1275/ofnet.c +++ b/grub-core/net/drivers/ieee1275/ofnet.c @@ -220,8 +220,7 @@ grub_ieee1275_parse_bootpath (const char *devpath, char *bootpath, flags); inter->vlantag = vlantag; grub_net_add_ipv4_local (inter, - __builtin_ctz (~grub_le_to_cpu32 (subnet_mask.ipv4))); - + __builtin_clz (~grub_be_to_cpu32 (subnet_mask.ipv4))); } if (gateway_addr.ipv4 != 0)