From: Chengen Du Date: Tue, 14 Jan 2025 04:12:34 +0000 (+0800) Subject: iscsi_ibft: Fix UBSAN shift-out-of-bounds warning in ibft_attr_show_nic() X-Git-Tag: v6.14-rc2~19^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=07e0d99a2f701123ad3104c0f1a1e66bce74d6e5;p=thirdparty%2Fkernel%2Flinux.git iscsi_ibft: Fix UBSAN shift-out-of-bounds warning in ibft_attr_show_nic() When performing an iSCSI boot using IPv6, iscsistart still reads the /sys/firmware/ibft/ethernetX/subnet-mask entry. Since the IPv6 prefix length is 64, this causes the shift exponent to become negative, triggering a UBSAN warning. As the concept of a subnet mask does not apply to IPv6, the value is set to ~0 to suppress the warning message. Signed-off-by: Chengen Du Signed-off-by: Konrad Rzeszutek Wilk --- diff --git a/drivers/firmware/iscsi_ibft.c b/drivers/firmware/iscsi_ibft.c index 6e9788324fea5..371f24569b3b2 100644 --- a/drivers/firmware/iscsi_ibft.c +++ b/drivers/firmware/iscsi_ibft.c @@ -310,7 +310,10 @@ static ssize_t ibft_attr_show_nic(void *data, int type, char *buf) str += sprintf_ipaddr(str, nic->ip_addr); break; case ISCSI_BOOT_ETH_SUBNET_MASK: - val = cpu_to_be32(~((1 << (32-nic->subnet_mask_prefix))-1)); + if (nic->subnet_mask_prefix > 32) + val = cpu_to_be32(~0); + else + val = cpu_to_be32(~((1 << (32-nic->subnet_mask_prefix))-1)); str += sprintf(str, "%pI4", &val); break; case ISCSI_BOOT_ETH_PREFIX_LEN: