chinmay1743/af_packet.cProof-Of-Concept to check privileges of af_packet.c for validating the privileges acquired by any hacker upon successful exploitation of CVE-2021-22600
用于检查 af_packet.c 权限的概念验证，以验证任何黑客在成功利用 CVE-2021-22600 后获得的权限。
这只是一个由 LLM 生成的示例概念验证，并未涵盖所有情况。 此概念验证的基本思想是检查目标代码以何种权限运行（例如用户空间还是内核空间），以了解利用围绕 CVE-2021-22600 构建的任何漏洞利用所带来的影响。 此代码绝非上述 CVE 的漏洞利用程序。我在虚拟机内的 Ubuntu 上进行了测试。您的结果可能因环境而异。
编译并运行代码的步骤：
gcc program.c -o runme
chmod +x runme
./runme
sudo ./runme
以普通用户身份运行时的示例输出：
<..SNIP..>
=== AF_PACKET privilege probe ===
UID=1000 EUID=1000
WARNING: couldn't read CapEff from /proc/self/status. Continuing anyway.
Stage 1: try AF_PACKET + SOCK_DGRAM (no CAP_NET_RAW required by kernel check)
socket(AF_PACKET, SOCK_DGRAM, ETH_P_ALL) => FAILED: Operation not permitted (errno=1)
Stage 2: try AF_PACKET + SOCK_RAW (kernel checks CAP_NET_RAW for SOCK_RAW)
socket(AF_PACKET, SOCK_RAW, ETH_P_ALL) => FAILED: Operation not permitted (errno=1)
RAW socket creation failed: you cannot reach packet_set_ring() from user-land without CAP_NET_RAW.
Common results:
- errno=EPERM (Operation not permitted) : you lack CAP_NET_RAW
- errno=EACCES : sometimes indicates policy or network namespace restrictions
Notes:
- The kernel enforces CAP_NET_RAW at socket creation: look for a check like
if (sock->type == SOCK_RAW && !capable(CAP_NET_RAW)) return -EPERM;
in net/packet/af_packet.c (this is why PACKET_RX_RING is unreachable without that socket).
- If you run this program as root or with CAP_NET_RAW, the RAW socket will succeed and
setsockopt(PACKET_RX_RING) will attempt to configure the ring (it may still fail with EINVAL
if your parameters are invalid, but you will have invoked packet_set_ring()).
=== Done ===
<..SNIP..>
以 sudo / root 用户身份运行时的示例输出：
<..SNIP..>
=== AF_PACKET privilege probe ===
UID=0 EUID=0
CapEff (hex) = 0x000001ffffffffff
-> CAP_NET_RAW (bit 12) = YES
Stage 1: try AF_PACKET + SOCK_DGRAM (no CAP_NET_RAW required by kernel check)
socket(AF_PACKET, SOCK_DGRAM, ETH_P_ALL) => OK (fd=3)
Stage 2: try AF_PACKET + SOCK_RAW (kernel checks CAP_NET_RAW for SOCK_RAW)
socket(AF_PACKET, SOCK_RAW, ETH_P_ALL) => OK (fd=3)
Since RAW socket creation succeeded, we likely have CAP_NET_RAW (or are root).
Stage 3: try setsockopt PACKET_RX_RING (this invokes packet_set_ring in kernel)
setsockopt(PACKET_RX_RING) => OK
Notes:
- The kernel enforces CAP_NET_RAW at socket creation: look for a check like
if (sock->type == SOCK_RAW && !capable(CAP_NET_RAW)) return -EPERM;
in net/packet/af_packet.c (this is why PACKET_RX_RING is unreachable without that socket).
- If you run this program as root or with CAP_NET_RAW, the RAW socket will succeed and
setsockopt(PACKET_RX_RING) will attempt to configure the ring (it may still fail with EINVAL
if your parameters are invalid, but you will have invoked packet_set_ring()).
=== Done ===
<..SNIP..>