From: Yonghong Song <yonghong.song@linux.dev> stable inclusion from stable-v6.6.121 commit a60c827903b45e2cbf45de782d0a14c2037e2122 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13686 CVE: CVE-2026-23140 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 4fc012daf9c074772421c904357abf586336b1ca ] The bpf selftest xdp_adjust_tail/xdp_adjust_frags_tail_grow failed on arm64 with 64KB page: xdp_adjust_tail/xdp_adjust_frags_tail_grow:FAIL In bpf_prog_test_run_xdp(), the xdp->frame_sz is set to 4K, but later on when constructing frags, with 64K page size, the frag data_len could be more than 4K. This will cause problems in bpf_xdp_frags_increase_tail(). To fix the failure, the xdp->frame_sz is set to be PAGE_SIZE so kernel can test different page size properly. With the kernel change, the user space and bpf prog needs adjustment. Currently, the MAX_SKB_FRAGS default value is 17, so for 4K page, the maximum packet size will be less than 68K. To test 64K page, a bigger maximum packet size than 68K is desired. So two different functions are implemented for subtest xdp_adjust_frags_tail_grow. Depending on different page size, different data input/output sizes are used to adapt with different page size. Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20250612035032.2207498-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> Stable-dep-of: e558cca21779 ("bpf, test_run: Subtract size of xdp_frame from allowed metadata size") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Li Xiasong <lixiasong1@huawei.com> --- net/bpf/test_run.c | 2 +- .../bpf/prog_tests/xdp_adjust_tail.c | 96 +++++++++++++++++-- .../bpf/progs/test_xdp_adjust_tail_grow.c | 8 +- 3 files changed, 97 insertions(+), 9 deletions(-) diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index e218bb7ab483..87b96b0d4c4e 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -1197,7 +1197,7 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, headroom -= ctx->data; } - max_data_sz = 4096 - headroom - tailroom; + max_data_sz = PAGE_SIZE - headroom - tailroom; if (size > max_data_sz) { /* disallow live data mode for jumbo frames */ if (do_live) diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c index 53d6ad8c2257..df90f5b4cee5 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c @@ -37,21 +37,26 @@ static void test_xdp_adjust_tail_shrink(void) bpf_object__close(obj); } -static void test_xdp_adjust_tail_grow(void) +static void test_xdp_adjust_tail_grow(bool is_64k_pagesize) { const char *file = "./test_xdp_adjust_tail_grow.bpf.o"; struct bpf_object *obj; - char buf[4096]; /* avoid segfault: large buf to hold grow results */ + char buf[8192]; /* avoid segfault: large buf to hold grow results */ __u32 expect_sz; int err, prog_fd; LIBBPF_OPTS(bpf_test_run_opts, topts, .data_in = &pkt_v4, - .data_size_in = sizeof(pkt_v4), .data_out = buf, .data_size_out = sizeof(buf), .repeat = 1, ); + /* topts.data_size_in as a special signal to bpf prog */ + if (is_64k_pagesize) + topts.data_size_in = sizeof(pkt_v4) - 1; + else + topts.data_size_in = sizeof(pkt_v4); + err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd); if (!ASSERT_OK(err, "test_xdp_adjust_tail_grow")) return; @@ -206,7 +211,7 @@ static void test_xdp_adjust_frags_tail_shrink(void) bpf_object__close(obj); } -static void test_xdp_adjust_frags_tail_grow(void) +static void test_xdp_adjust_frags_tail_grow_4k(void) { const char *file = "./test_xdp_adjust_tail_grow.bpf.o"; __u32 exp_size; @@ -271,16 +276,93 @@ static void test_xdp_adjust_frags_tail_grow(void) bpf_object__close(obj); } +static void test_xdp_adjust_frags_tail_grow_64k(void) +{ + const char *file = "./test_xdp_adjust_tail_grow.bpf.o"; + __u32 exp_size; + struct bpf_program *prog; + struct bpf_object *obj; + int err, i, prog_fd; + __u8 *buf; + LIBBPF_OPTS(bpf_test_run_opts, topts); + + obj = bpf_object__open(file); + if (libbpf_get_error(obj)) + return; + + prog = bpf_object__next_program(obj, NULL); + if (bpf_object__load(obj)) + goto out; + + prog_fd = bpf_program__fd(prog); + + buf = malloc(262144); + if (!ASSERT_OK_PTR(buf, "alloc buf 256Kb")) + goto out; + + /* Test case add 10 bytes to last frag */ + memset(buf, 1, 262144); + exp_size = 90000 + 10; + + topts.data_in = buf; + topts.data_out = buf; + topts.data_size_in = 90000; + topts.data_size_out = 262144; + err = bpf_prog_test_run_opts(prog_fd, &topts); + + ASSERT_OK(err, "90Kb+10b"); + ASSERT_EQ(topts.retval, XDP_TX, "90Kb+10b retval"); + ASSERT_EQ(topts.data_size_out, exp_size, "90Kb+10b size"); + + for (i = 0; i < 90000; i++) { + if (buf[i] != 1) + ASSERT_EQ(buf[i], 1, "90Kb+10b-old"); + } + + for (i = 90000; i < 90010; i++) { + if (buf[i] != 0) + ASSERT_EQ(buf[i], 0, "90Kb+10b-new"); + } + + for (i = 90010; i < 262144; i++) { + if (buf[i] != 1) + ASSERT_EQ(buf[i], 1, "90Kb+10b-untouched"); + } + + /* Test a too large grow */ + memset(buf, 1, 262144); + exp_size = 90001; + + topts.data_in = topts.data_out = buf; + topts.data_size_in = 90001; + topts.data_size_out = 262144; + err = bpf_prog_test_run_opts(prog_fd, &topts); + + ASSERT_OK(err, "90Kb+10b"); + ASSERT_EQ(topts.retval, XDP_DROP, "90Kb+10b retval"); + ASSERT_EQ(topts.data_size_out, exp_size, "90Kb+10b size"); + + free(buf); +out: + bpf_object__close(obj); +} + void test_xdp_adjust_tail(void) { + int page_size = getpagesize(); + if (test__start_subtest("xdp_adjust_tail_shrink")) test_xdp_adjust_tail_shrink(); if (test__start_subtest("xdp_adjust_tail_grow")) - test_xdp_adjust_tail_grow(); + test_xdp_adjust_tail_grow(page_size == 65536); if (test__start_subtest("xdp_adjust_tail_grow2")) test_xdp_adjust_tail_grow2(); if (test__start_subtest("xdp_adjust_frags_tail_shrink")) test_xdp_adjust_frags_tail_shrink(); - if (test__start_subtest("xdp_adjust_frags_tail_grow")) - test_xdp_adjust_frags_tail_grow(); + if (test__start_subtest("xdp_adjust_frags_tail_grow")) { + if (page_size == 65536) + test_xdp_adjust_frags_tail_grow_64k(); + else + test_xdp_adjust_frags_tail_grow_4k(); + } } diff --git a/tools/testing/selftests/bpf/progs/test_xdp_adjust_tail_grow.c b/tools/testing/selftests/bpf/progs/test_xdp_adjust_tail_grow.c index 81bb38d72ced..e311e206be07 100644 --- a/tools/testing/selftests/bpf/progs/test_xdp_adjust_tail_grow.c +++ b/tools/testing/selftests/bpf/progs/test_xdp_adjust_tail_grow.c @@ -17,7 +17,9 @@ int _xdp_adjust_tail_grow(struct xdp_md *xdp) /* Data length determine test case */ if (data_len == 54) { /* sizeof(pkt_v4) */ - offset = 4096; /* test too large offset */ + offset = 4096; /* test too large offset, 4k page size */ + } else if (data_len == 53) { /* sizeof(pkt_v4) - 1 */ + offset = 65536; /* test too large offset, 64k page size */ } else if (data_len == 74) { /* sizeof(pkt_v6) */ offset = 40; } else if (data_len == 64) { @@ -29,6 +31,10 @@ int _xdp_adjust_tail_grow(struct xdp_md *xdp) offset = 10; } else if (data_len == 9001) { offset = 4096; + } else if (data_len == 90000) { + offset = 10; /* test a small offset, 64k page size */ + } else if (data_len == 90001) { + offset = 65536; /* test too large offset, 64k page size */ } else { return XDP_ABORTED; /* No matching test */ } -- 2.34.1