CVE-2025-71096

In the Linux kernel, the following vulnerability has been resolved:

RDMA/core: Check for the presence of LS_NLA_TYPE_DGID correctly

The netlink response for RDMA_NL_LS_OP_IP_RESOLVE should always have a

LS_NLA_TYPE_DGID attribute, it is invalid if it does not.

Use the nl parsing logic properly and call nla_parse_deprecated() to fill

the nlattrs array and then directly index that array to get the data for

the DGID. Just fail if it is NULL.

Remove the for loop searching for the nla, and squash the validation and

parsing into one function.

Fixes an uninitialized read from the stack triggered by userspace if it

does not provide the DGID to a kernel initiated RDMA_NL_LS_OP_IP_RESOLVE

query.

BUG: KMSAN: uninit-value in hex_byte_pack include/linux/hex.h:13 [inline]

BUG: KMSAN: uninit-value in ip6_string+0xef4/0x13a0 lib/vsprintf.c:1490

hex_byte_pack include/linux/hex.h:13 [inline]

ip6_string+0xef4/0x13a0 lib/vsprintf.c:1490

ip6_addr_string+0x18a/0x3e0 lib/vsprintf.c:1509

ip_addr_string+0x245/0xee0 lib/vsprintf.c:1633

pointer+0xc09/0x1bd0 lib/vsprintf.c:2542

vsnprintf+0xf8a/0x1bd0 lib/vsprintf.c:2930

vprintk_store+0x3ae/0x1530 kernel/printk/printk.c:2279

vprintk_emit+0x307/0xcd0 kernel/printk/printk.c:2426

vprintk_default+0x3f/0x50 kernel/printk/printk.c:2465

vprintk+0x36/0x50 kernel/printk/printk_safe.c:82

_printk+0x17e/0x1b0 kernel/printk/printk.c:2475

ib_nl_process_good_ip_rsep drivers/infiniband/core/addr.c:128 [inline]

ib_nl_handle_ip_res_resp+0x963/0x9d0 drivers/infiniband/core/addr.c:141

rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:-1 [inline]

rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]

rdma_nl_rcv+0xefa/0x11c0 drivers/infiniband/core/netlink.c:259

netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]

netlink_unicast+0xf04/0x12b0 net/netlink/af_netlink.c:1346

netlink_sendmsg+0x10b3/0x1250 net/netlink/af_netlink.c:1896

sock_sendmsg_nosec net/socket.c:714 [inline]

__sock_sendmsg+0x333/0x3d0 net/socket.c:729

____sys_sendmsg+0x7e0/0xd80 net/socket.c:2617

___sys_sendmsg+0x271/0x3b0 net/socket.c:2671

__sys_sendmsg+0x1aa/0x300 net/socket.c:2703

__compat_sys_sendmsg net/compat.c:346 [inline]

__do_compat_sys_sendmsg net/compat.c:353 [inline]

__se_compat_sys_sendmsg net/compat.c:350 [inline]

__ia32_compat_sys_sendmsg+0xa4/0x100 net/compat.c:350

ia32_sys_call+0x3f6c/0x4310 arch/x86/include/generated/asm/syscalls_32.h:371

do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]

__do_fast_syscall_32+0xb0/0x150 arch/x86/entry/syscall_32.c:306

do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331

do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:3