In a follow up to these patches,
- commit 0bdf399342c5("net: Avoid address overwrite in kernel_connect") - commit 86a7e0b69bd5("net: prevent rewrite of msg_name in sock_sendmsg()") - commit c889a99a21bf("net: prevent address rewrite in kernel_bind()") - commit 01b2885d9415("net: Save and restore msg_namelen in sock_sendmsg")
this patch series introduces BPF selftests that test the interaction between BPF sockaddr hooks and socket operations in kernel space. It focuses on regression test coverage to ensure that these operations do not overwrite their address parameter and also provides some sanity checks around kernel_getpeername() and kernel_getsockname().
It introduces two new components: a kernel module called sock_addr_testmod and a new test program called sock_addr_kern which is loosely modeled after and adapted from the old-style bpf/test_sock_addr.c selftest. When loaded, the kernel module will perform some socket operation in kernel space. The kernel module accepts five parameters controlling which socket operation will be performed and its inputs:
MODULE_PARM_DESC(ip, "IPv4/IPv6/Unix address to use for socket operation"); MODULE_PARM_DESC(port, "Port number to use for socket operation"); MODULE_PARM_DESC(af, "Address family (AF_INET, AF_INET6, or AF_UNIX)"); MODULE_PARM_DESC(type, "Socket type (SOCK_STREAM or SOCK_DGRAM)"); MODULE_PARM_DESC(op, "Socket operation (BIND=0, CONNECT=1, SENDMSG=2)");
On module init, the socket operation is performed and results of are exposed through debugfs.
- /sys/kernel/debug/sock_addr_testmod/success Indicates success or failure of the operation. - /sys/kernel/debug/sock_addr_testmod/addr The value of the address parameter after the operation. - /sys/kernel/debug/sock_addr_testmod/sock_name The value of kernel_getsockname() after the socket operation (if relevant). - /sys/kernel/debug/sock_addr_testmod/peer_name The value of kernel_getpeername(() after the socket operation (if relevant).
The sock_addr_kern test program loads and unloads the kernel module to drive kernel socket operations, reads the results from debugfs, makes sure that the operation did not overwrite the address, and any result from kernel_getpeername() or kernel_getsockname() were as expected.
== Patches ==
- Patch 1 introduces sock_addr_testmod and functions necessary for the test program to load and unload the module. - Patches 2-6 transform existing test helpers and introduce new test helpers to enable the sock_addr_kern test program. - Patch 7 implements the sock_addr_kern test program. - Patch 8 fixes the sock_addr bind test program to work for big endian architectures such as s390x.
Jordan Rife (8): selftests/bpf: Introduce sock_addr_testmod selftests/bpf: Add module load helpers selftests/bpf: Factor out cmp_addr selftests/bpf: Add recv_msg_from_client to network helpers selftests/bpf: Factor out load_path and defines from test_sock_addr selftests/bpf: Add setup/cleanup subcommands selftests/bpf: Add sock_addr_kern prog_test selftests/bpf: Fix bind program for big endian systems
tools/testing/selftests/bpf/Makefile | 46 +- tools/testing/selftests/bpf/network_helpers.c | 65 ++ tools/testing/selftests/bpf/network_helpers.h | 5 + .../selftests/bpf/prog_tests/sock_addr.c | 34 - .../selftests/bpf/prog_tests/sock_addr_kern.c | 631 ++++++++++++++++++ .../testing/selftests/bpf/progs/bind4_prog.c | 18 +- .../testing/selftests/bpf/progs/bind6_prog.c | 18 +- tools/testing/selftests/bpf/progs/bind_prog.h | 19 + .../testing/selftests/bpf/sock_addr_helpers.c | 46 ++ .../testing/selftests/bpf/sock_addr_helpers.h | 44 ++ .../bpf/sock_addr_testmod/.gitignore | 6 + .../selftests/bpf/sock_addr_testmod/Makefile | 20 + .../bpf/sock_addr_testmod/sock_addr_testmod.c | 256 +++++++ tools/testing/selftests/bpf/test_sock_addr.c | 76 +-- tools/testing/selftests/bpf/test_sock_addr.sh | 10 +- tools/testing/selftests/bpf/testing_helpers.c | 44 +- tools/testing/selftests/bpf/testing_helpers.h | 2 + 17 files changed, 1196 insertions(+), 144 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/sock_addr_kern.c create mode 100644 tools/testing/selftests/bpf/progs/bind_prog.h create mode 100644 tools/testing/selftests/bpf/sock_addr_helpers.c create mode 100644 tools/testing/selftests/bpf/sock_addr_helpers.h create mode 100644 tools/testing/selftests/bpf/sock_addr_testmod/.gitignore create mode 100644 tools/testing/selftests/bpf/sock_addr_testmod/Makefile create mode 100644 tools/testing/selftests/bpf/sock_addr_testmod/sock_addr_testmod.c