CVE-2024-50128

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

net: wwan: fix global oob in wwan_rtnl_policy

The variable wwan_rtnl_link_ops assign a bigger maxtype which leads to a global out-of-bounds read when parsing the netlink attributes. Exactly same bug cause as the oob fixed in commit b33fb5b801c6 (net: qualcomm: rmnet: fix global oob in rmnet_policy).

================================================================== BUG: KASAN: global-out-of-bounds in validate_nla lib/nlattr.c:388 [inline] BUG: KASAN: global-out-of-bounds in __nla_validate_parse+0x19d7/0x29a0 lib/nlattr.c:603 Read of size 1 at addr ffffffff8b09cb60 by task syz.1.66276/323862

CPU: 0 PID: 323862 Comm: syz.1.66276 Not tainted 6.1.70 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x177/0x231 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [inline] print_report+0x14f/0x750 mm/kasan/report.c:395 kasan_report+0x139/0x170 mm/kasan/report.c:495 validate_nla lib/nlattr.c:388 [inline] __nla_validate_parse+0x19d7/0x29a0 lib/nlattr.c:603 __nla_parse+0x3c/0x50 lib/nlattr.c:700 nla_parse_nested_deprecated include/net/netlink.h:1269 [inline] __rtnl_newlink net/core/rtnetlink.c:3514 [inline] rtnl_newlink+0x7bc/0x1fd0 net/core/rtnetlink.c:3623 rtnetlink_rcv_msg+0x794/0xef0 net/core/rtnetlink.c:6122 netlink_rcv_skb+0x1de/0x420 net/netlink/af_netlink.c:2508 netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline] netlink_unicast+0x74b/0x8c0 net/netlink/af_netlink.c:1352 netlink_sendmsg+0x882/0xb90 net/netlink/af_netlink.c:1874 sock_sendmsg_nosec net/socket.c:716 [inline] __sock_sendmsg net/socket.c:728 [inline] ____sys_sendmsg+0x5cc/0x8f0 net/socket.c:2499 ___sys_sendmsg+0x21c/0x290 net/socket.c:2553 __sys_sendmsg net/socket.c:2582 [inline] __do_sys_sendmsg net/socket.c:2591 [inline] __se_sys_sendmsg+0x19e/0x270 net/socket.c:2589 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x45/0x90 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f67b19a24ad RSP: 002b:00007f67b17febb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f67b1b45f80 RCX: 00007f67b19a24ad RDX: 0000000000000000 RSI: 0000000020005e40 RDI: 0000000000000004 RBP: 00007f67b1a1e01d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd2513764f R14: 00007ffd251376e0 R15: 00007f67b17fed40

The buggy address belongs to the variable: wwan_rtnl_policy+0x20/0x40

The buggy address belongs to the physical page: page:ffffea00002c2700 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xb09c flags: 0xfff00000001000(reserved|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000001000 ffffea00002c2708 ffffea00002c2708 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner info is not present (never set?)

Memory state around the buggy address: ffffffff8b09ca00: 05 f9 f9 f9 05 f9 f9 f9 00 01 f9 f9 00 01 f9 f9 ffffffff8b09ca80: 00 00 00 05 f9 f9 f9 f9 00 00 03 f9 f9 f9 f9 f9

ffffffff8b09cb00: 00 00 00 00 05 f9 f9 f9 00 00 00 00 f9 f9 f9 f9 ^ ffffffff8b09cb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================

According to the comment of nla_parse_nested_deprecated, use correct size IFLA_WWAN_MAX here to fix this issue.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/47dd5447cab8ce30a847a0337d5341ae4c7476a7
• https://git.kernel.org/stable/c/69076f8435c1c5dae5f814eaf4c361d1f00b22a3
• https://git.kernel.org/stable/c/9683804e36668f6093fb06e202eed2f188ba437e
• https://git.kernel.org/stable/c/a3ffce63dcc0c208edd4d196e17baed22ebcb643
• https://git.kernel.org/stable/c/c9a0aed51977198df005d0a623090e38e2d77d7b
• https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html