We can reproduce the issue using the existing test program: './test_sockmap --ktls' Or use the selftest I provided, which will cause a panic:
------------[ cut here ]------------ kernel BUG at lib/iov_iter.c:629!
PKRU: 55555554 Call Trace: <TASK> ? die+0x36/0x90 ? do_trap+0xdd/0x100 ? iov_iter_revert+0x178/0x180 ? iov_iter_revert+0x178/0x180 ? do_error_trap+0x7d/0x110 ? iov_iter_revert+0x178/0x180 ? exc_invalid_op+0x50/0x70 ? iov_iter_revert+0x178/0x180 ? asm_exc_invalid_op+0x1a/0x20 ? iov_iter_revert+0x178/0x180 ? iov_iter_revert+0x5c/0x180 tls_sw_sendmsg_locked.isra.0+0x794/0x840 tls_sw_sendmsg+0x52/0x80 ? inet_sendmsg+0x1f/0x70 __sys_sendto+0x1cd/0x200 ? find_held_lock+0x2b/0x80 ? syscall_trace_enter+0x140/0x270 ? __lock_release.isra.0+0x5e/0x170 ? find_held_lock+0x2b/0x80 ? syscall_trace_enter+0x140/0x270 ? lockdep_hardirqs_on_prepare+0xda/0x190 ? ktime_get_coarse_real_ts64+0xc2/0xd0 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x90/0x170
1. It looks like the issue started occurring after bpf being introduced to ktls and later the addition of assertions to iov_iter has caused a panic. If my fix tag is incorrect, please assist me in correcting the fix tag.
2. I make minimal changes for now, it's enough to make ktls work correctly.
--- v1->v2: Added more content to the commit message https://lore.kernel.org/all/20250123171552.57345-1-mrpre@163.com/#r ---
Jiayuan Chen (2): bpf: fix ktls panic with sockmap selftests/bpf: add ktls selftest
net/tls/tls_sw.c | 8 +- .../selftests/bpf/prog_tests/sockmap_ktls.c | 174 +++++++++++++++++- .../selftests/bpf/progs/test_sockmap_ktls.c | 26 +++ 3 files changed, 205 insertions(+), 3 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/test_sockmap_ktls.c
[ 2172.936997] ------------[ cut here ]------------ [ 2172.936999] kernel BUG at lib/iov_iter.c:629! ...... [ 2172.944996] PKRU: 55555554 [ 2172.945155] Call Trace: [ 2172.945299] <TASK> [ 2172.945428] ? die+0x36/0x90 [ 2172.945601] ? do_trap+0xdd/0x100 [ 2172.945795] ? iov_iter_revert+0x178/0x180 [ 2172.946031] ? iov_iter_revert+0x178/0x180 [ 2172.946267] ? do_error_trap+0x7d/0x110 [ 2172.946499] ? iov_iter_revert+0x178/0x180 [ 2172.946736] ? exc_invalid_op+0x50/0x70 [ 2172.946961] ? iov_iter_revert+0x178/0x180 [ 2172.947197] ? asm_exc_invalid_op+0x1a/0x20 [ 2172.947446] ? iov_iter_revert+0x178/0x180 [ 2172.947683] ? iov_iter_revert+0x5c/0x180 [ 2172.947913] tls_sw_sendmsg_locked.isra.0+0x794/0x840 [ 2172.948206] tls_sw_sendmsg+0x52/0x80 [ 2172.948420] ? inet_sendmsg+0x1f/0x70 [ 2172.948634] __sys_sendto+0x1cd/0x200 [ 2172.948848] ? find_held_lock+0x2b/0x80 [ 2172.949072] ? syscall_trace_enter+0x140/0x270 [ 2172.949330] ? __lock_release.isra.0+0x5e/0x170 [ 2172.949595] ? find_held_lock+0x2b/0x80 [ 2172.949817] ? syscall_trace_enter+0x140/0x270 [ 2172.950211] ? lockdep_hardirqs_on_prepare+0xda/0x190 [ 2172.950632] ? ktime_get_coarse_real_ts64+0xc2/0xd0 [ 2172.951036] __x64_sys_sendto+0x24/0x30 [ 2172.951382] do_syscall_64+0x90/0x170 ......
After calling bpf_exec_tx_verdict(), the size of msg_pl->sg may increase, e.g., when the BPF program executes bpf_msg_push_data().
If the BPF program sets cork_bytes and sg.size is smaller than cork_bytes, it will return -ENOSPC and attempt to roll back to the non-zero copy logic. However, during rollback, msg->msg_iter is reset, but since msg_pl->sg.size has been increased, subsequent executions will exceed the actual size of msg_iter. ''' iov_iter_revert(&msg->msg_iter, msg_pl->sg.size - orig_size); '''
The changes in this commit are based on the following considerations:
1. When cork_bytes is set, rolling back to non-zero copy logic is pointless and can directly go to zero-copy logic.
2. We can not calculate the correct number of bytes to revert msg_iter.
Assume the original data is "abcdefgh" (8 bytes), and after 3 pushes by the BPF program, it becomes 11-byte data: "abc?de?fgh?". Then, we set cork_bytes to 6, which means the first 6 bytes have been processed, and the remaining 5 bytes "?fgh?" will be cached until the length meets the cork_bytes requirement.
However, some data in "?fgh?" is not within 'sg->msg_iter' (but in msg_pl instead), especially the data "?" we pushed.
So it doesn't seem as simple as just reverting through an offset of msg_iter.
3. For non-TLS sockets in tcp_bpf_sendmsg, when a "cork" situation occurs, the user-space send() doesn't return an error, and the returned length is the same as the input length parameter, even if some data is cached.
Additionally, I saw that the current non-zero-copy logic for handling corking is written as: ''' line 1177 else if (ret != -EAGAIN) { if (ret == -ENOSPC) ret = 0; goto send_end; '''
So it's ok to just return 'copied' without error when a "cork" situation occurs.
Fixes: fcb14cb1bdac ("new iov_iter flavour - ITER_UBUF") Fixes: d3b18ad31f93 ("tls: add bpf support to sk_msg handling") Signed-off-by: Jiayuan Chen jiayuan.chen@linux.dev --- net/tls/tls_sw.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 914d4e1516a3..f3d7d19482da 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1120,9 +1120,13 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg, num_async++; else if (ret == -ENOMEM) goto wait_for_memory; - else if (ctx->open_rec && ret == -ENOSPC) + else if (ctx->open_rec && ret == -ENOSPC) { + if (msg_pl->cork_bytes) { + ret = 0; + goto send_end; + } goto rollback_iter; - else if (ret != -EAGAIN) + } else if (ret != -EAGAIN) goto send_end; } continue;
add ktls selftest for sockmap
Test results: sockmap_ktls/sockmap_ktls disconnect_after_delete IPv4 SOCKMAP:OK sockmap_ktls/sockmap_ktls update_fails_when_sock_has_ulp IPv4 SOCKMAP:OK sockmap_ktls/sockmap_ktls disconnect_after_delete IPv4 SOCKMAP:OK sockmap_ktls/sockmap_ktls update_fails_when_sock_has_ulp IPv4 SOCKMAP:OK sockmap_ktls/sockmap_ktls disconnect_after_delete IPv4 SOCKMAP:OK sockmap_ktls/sockmap_ktls update_fails_when_sock_has_ulp IPv4 SOCKMAP:OK sockmap_ktls/sockmap_ktls disconnect_after_delete IPv4 SOCKMAP:OK sockmap_ktls/sockmap_ktls update_fails_when_sock_has_ulp IPv4 SOCKMAP:OK sockmap_ktls/tls simple offload:OK sockmap_ktls/tls tx cork:OK sockmap_ktls/tls tx cork with push:OK sockmap_ktls/tls simple offload:OK sockmap_ktls/tls tx cork:OK sockmap_ktls/tls tx cork with push:OK sockmap_ktls:OK
Signed-off-by: Jiayuan Chen jiayuan.chen@linux.dev --- .../selftests/bpf/prog_tests/sockmap_ktls.c | 174 +++++++++++++++++- .../selftests/bpf/progs/test_sockmap_ktls.c | 26 +++ 2 files changed, 199 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/progs/test_sockmap_ktls.c
diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c index 2d0796314862..49b85c1c7552 100644 --- a/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c @@ -3,13 +3,64 @@ /* * Tests for sockmap/sockhash holding kTLS sockets. */ - +#include <error.h> #include <netinet/tcp.h> +#include <linux/tls.h> #include "test_progs.h" +#include "sockmap_helpers.h" +#include "test_skmsg_load_helpers.skel.h" +#include "test_sockmap_ktls.skel.h"
#define MAX_TEST_NAME 80 #define TCP_ULP 31
+static int init_ktls_pairs(int c, int p) +{ + int err; + struct tls12_crypto_info_aes_gcm_128 crypto_rx; + struct tls12_crypto_info_aes_gcm_128 crypto_tx; + + err = setsockopt(c, IPPROTO_TCP, TCP_ULP, "tls", strlen("tls")); + if (!ASSERT_OK(err, "setsockopt(TCP_ULP)")) + goto out; + + err = setsockopt(p, IPPROTO_TCP, TCP_ULP, "tls", strlen("tls")); + if (!ASSERT_OK(err, "setsockopt(TCP_ULP)")) + goto out; + + memset(&crypto_rx, 0, sizeof(crypto_rx)); + memset(&crypto_tx, 0, sizeof(crypto_tx)); + crypto_rx.info.version = TLS_1_2_VERSION; + crypto_tx.info.version = TLS_1_2_VERSION; + crypto_rx.info.cipher_type = TLS_CIPHER_AES_GCM_128; + crypto_tx.info.cipher_type = TLS_CIPHER_AES_GCM_128; + + err = setsockopt(c, SOL_TLS, TLS_TX, &crypto_tx, sizeof(crypto_tx)); + if (!ASSERT_OK(err, "setsockopt(TLS_TX)")) + goto out; + + err = setsockopt(p, SOL_TLS, TLS_RX, &crypto_rx, sizeof(crypto_rx)); + if (!ASSERT_OK(err, "setsockopt(TLS_RX)")) + goto out; + return 0; +out: + return -1; +} + +static int create_ktls_pairs(int family, int sotype, int *c, int *p) +{ + int err; + + err = create_pair(family, sotype, c, p); + if (!ASSERT_OK(err, "create_pair()")) + return -1; + + err = init_ktls_pairs(*c, *p); + if (!ASSERT_OK(err, "init_ktls_pairs(c, p)")) + return -1; + return 0; +} + static int tcp_server(int family) { int err, s; @@ -146,6 +197,115 @@ static const char *fmt_test_name(const char *subtest_name, int family, return test_name; }
+static void test_sockmap_ktls_offload(int family, int sotype) +{ + int err; + int c = 0, p = 0, sent, recvd; + char msg[12] = "hello world\0"; + char rcv[13]; + + err = create_ktls_pairs(family, sotype, &c, &p); + if (!ASSERT_OK(err, "create_ktls_pairs()")) + goto out; + + sent = send(c, msg, sizeof(msg), 0); + if (!ASSERT_OK(err, "send(msg)")) + goto out; + + recvd = recv(p, rcv, sizeof(rcv), 0); + if (!ASSERT_OK(err, "recv(msg)") || + !ASSERT_EQ(recvd, sent, "length mismatch")) + goto out; + + ASSERT_OK(memcmp(msg, rcv, sizeof(msg)), "data mismatch"); + +out: + if (c) + close(c); + if (p) + close(p); +} + +static void test_sockmap_ktls_tx_cork(int family, int sotype, bool push) +{ + int err, off; + int i, j; + int start_push = 0, push_len = 0; + int c = 0, p = 0, one = 1, sent, recvd; + int prog_fd, map_fd; + char msg[12] = "hello world\0"; + char rcv[20] = {0}; + struct test_sockmap_ktls *skel; + + skel = test_sockmap_ktls__open_and_load(); + if (!ASSERT_TRUE(skel, "open ktls skel")) + return; + + err = create_pair(family, sotype, &c, &p); + if (!ASSERT_OK(err, "create_pair()")) + goto out; + + prog_fd = bpf_program__fd(skel->progs.prog_sk_policy); + map_fd = bpf_map__fd(skel->maps.sock_map); + + err = bpf_prog_attach(prog_fd, map_fd, BPF_SK_MSG_VERDICT, 0); + if (!ASSERT_OK(err, "bpf_prog_attach sk msg")) + goto out; + + err = bpf_map_update_elem(map_fd, &one, &c, BPF_NOEXIST); + if (!ASSERT_OK(err, "bpf_map_update_elem(c)")) + goto out; + + err = init_ktls_pairs(c, p); + if (!ASSERT_OK(err, "init_ktls_pairs(c, p)")) + goto out; + + skel->bss->cork_byte = sizeof(msg); + if (push) { + start_push = 1; + push_len = 2; + } + skel->bss->push_start = start_push; + skel->bss->push_end = push_len; + + off = sizeof(msg) / 2; + sent = send(c, msg, off, 0); + if (!ASSERT_EQ(sent, off, "send(msg)")) + goto out; + + recvd = recv_timeout(p, rcv, sizeof(rcv), MSG_DONTWAIT, 1); + if (!ASSERT_EQ(-1, recvd, "expected no data")) + goto out; + + /* send remaining msg */ + sent = send(c, msg + off, sizeof(msg) - off, 0); + if (!ASSERT_EQ(sent, sizeof(msg) - off, "send remaining data")) + goto out; + + recvd = recv_timeout(p, rcv, sizeof(rcv), MSG_DONTWAIT, 1); + if (!ASSERT_OK(err, "recv(msg)") || + !ASSERT_EQ(recvd, sizeof(msg) + push_len, "check length mismatch")) + goto out; + + for (i = 0, j = 0; i < recvd;) { + /* skip checking the data that has been pushed in */ + if (i >= start_push && i <= start_push + push_len - 1) { + i++; + continue; + } + if (!ASSERT_EQ(rcv[i], msg[j], "data mismatch")) + goto out; + i++; + j++; + } +out: + if (c) + close(c); + if (p) + close(p); + test_sockmap_ktls__destroy(skel); +} + static void run_tests(int family, enum bpf_map_type map_type) { int map; @@ -162,10 +322,22 @@ static void run_tests(int family, enum bpf_map_type map_type) close(map); }
+static void run_ktls_test(int family, int sotype) +{ + if (test__start_subtest("tls simple offload")) + test_sockmap_ktls_offload(family, sotype); + if (test__start_subtest("tls tx cork")) + test_sockmap_ktls_tx_cork(family, sotype, false); + if (test__start_subtest("tls tx cork with push")) + test_sockmap_ktls_tx_cork(family, sotype, true); +} + void test_sockmap_ktls(void) { run_tests(AF_INET, BPF_MAP_TYPE_SOCKMAP); run_tests(AF_INET, BPF_MAP_TYPE_SOCKHASH); run_tests(AF_INET6, BPF_MAP_TYPE_SOCKMAP); run_tests(AF_INET6, BPF_MAP_TYPE_SOCKHASH); + run_ktls_test(AF_INET, SOCK_STREAM); + run_ktls_test(AF_INET6, SOCK_STREAM); } diff --git a/tools/testing/selftests/bpf/progs/test_sockmap_ktls.c b/tools/testing/selftests/bpf/progs/test_sockmap_ktls.c new file mode 100644 index 000000000000..e0f757929ef4 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_sockmap_ktls.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_endian.h> + +int cork_byte; +int push_start; +int push_end; + +struct { + __uint(type, BPF_MAP_TYPE_SOCKMAP); + __uint(max_entries, 20); + __type(key, int); + __type(value, int); +} sock_map SEC(".maps"); + +SEC("sk_msg") +int prog_sk_policy(struct sk_msg_md *msg) +{ + if (cork_byte > 0) + bpf_msg_cork_bytes(msg, cork_byte); + if (push_start > 0 && push_end > 0) + bpf_msg_push_data(msg, push_start, push_end, 0); + + return SK_PASS; +}
linux-kselftest-mirror@lists.linaro.org
-
Jiayuan Chen