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[2a03:2880:31ff:23::face:b00c]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-434d52cc2fdsm73726415e9.42.2024.12.05.14.31.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Dec 2024 14:31:56 -0800 (PST) From: Kumar Kartikeya Dwivedi To: bpf@vger.kernel.org Cc: kkd@meta.com, Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Eduard Zingerman , Manu Bretelle , kernel-team@fb.com Subject: [PATCH bpf v2 2/2] selftests/bpf: Add raw_tp tests for PTR_MAYBE_NULL marking Date: Thu, 5 Dec 2024 14:31:52 -0800 Message-ID: <20241205223152.2434683-3-memxor@gmail.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20241205223152.2434683-1-memxor@gmail.com> References: <20241205223152.2434683-1-memxor@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3974; h=from:subject; bh=UF86Z1dQj/KsU3Ra+wcuwqEKaKGOLHEpyZ1QKIxoEbg=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBnUii0hpXQXNM/hzCfatvKyRsKljBnCNHMipsqlOu6 jngTTKCJAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCZ1IotAAKCRBM4MiGSL8RyohZD/ 9v+WveMuXnISgRD0Z0Nt+u1u6DRy6IGlv1LE1TekDcSOZ/VIB0Yie5ItZBXstyxH3gIITT/TDD1zRU mlL7y1J91bDMowqYuBP8nfMx1IogBaAcY3ZzgpTL9w86SS2Lfsm9jNB1+AsfR4SoKmGItFHSGoB4IP 87gn1UuRxsMC1Bvh44IUo+FuRz10YOOIvk8SnbbYpZWdEOz7FP9bJXJaJGhauT8M7fIQxaMTrwAUlF ipcvM4M3dfxmpY89+S1PM2l5XnlNrjKOvfLlMfj9xbbMdtMxXFspG9hOENoCYB+a/Ej+/k/QEpcgF2 5MG+kAY8Mj1Xpp+OS/hGdMF/3nkxNrmCeKcZ50Dp2Zjj4C7tvJP/ZaBT7ij2Vix1/q5Arbgasa2K5J mfVALfPf+WOtOgDrMClr+RMPAQdrRWFCtmqokTeE0IuvBz45r9Ut/pWQwKjJP/Va0MERt2wztoC5T5 SqpNq2UNlh08cf9PxoWtjIqX/tL3LEhmTn2lvNpJ2B4u5Bk/dBeRrJ4MDrjXbtWct76qYaCJTARIy4 X+nUF7qmOdfEXxUp28krQ5+y58HnuIdeCSGvh/sDLDsB6ApYWf1eAefEOIvktEVhA04hzqgl1g3peR VR5Es9RVb23cg8kj5Ey07pxcDLSQjUbWCYuJB/LX8+o8r6dT+CfqFNkCohXg== X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=4BBE2A7E06ECF9D5823C61114CE0C88648BF11CA X-Patchwork-Delegate: bpf@iogearbox.net Ensure that pointers with off != 0 are never unmarked as PTR_MAYBE_NULL when doing NULL checks, while pointers that have off == 0 continue getting unmarked, and also unmark associated copies with same id but possibly non-zero offset. Signed-off-by: Kumar Kartikeya Dwivedi Acked-by: Eduard Zingerman --- .../selftests/bpf/prog_tests/raw_tp_null.c | 6 ++ .../selftests/bpf/progs/raw_tp_null_fail.c | 80 +++++++++++++++++++ 2 files changed, 86 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/raw_tp_null_fail.c diff --git a/tools/testing/selftests/bpf/prog_tests/raw_tp_null.c b/tools/testing/selftests/bpf/prog_tests/raw_tp_null.c index 6fa19449297e..13fcd4c31034 100644 --- a/tools/testing/selftests/bpf/prog_tests/raw_tp_null.c +++ b/tools/testing/selftests/bpf/prog_tests/raw_tp_null.c @@ -3,6 +3,12 @@ #include #include "raw_tp_null.skel.h" +#include "raw_tp_null_fail.skel.h" + +void test_raw_tp_null_fail(void) +{ + RUN_TESTS(raw_tp_null_fail); +} void test_raw_tp_null(void) { diff --git a/tools/testing/selftests/bpf/progs/raw_tp_null_fail.c b/tools/testing/selftests/bpf/progs/raw_tp_null_fail.c new file mode 100644 index 000000000000..68de752cfe53 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/raw_tp_null_fail.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include "bpf_misc.h" + +/* r1 with off=0 is checked, which marks r0 with off=8 as non-null */ +SEC("tp_btf/bpf_testmod_test_raw_tp_null") +__success +__log_level(2) +__msg("3: (07) r0 += 8 ; R0_w=trusted_ptr_or_null_sk_buff(id=1,off=8)") +__msg("4: (15) if r1 == 0x0 goto pc+1 ; R1_w=trusted_ptr_sk_buff()") +__msg("5: (bf) r2 = r0 ; R0_w=trusted_ptr_sk_buff(off=8)") +int BPF_PROG(test_raw_tp_null_check_zero_off, struct sk_buff *skb) +{ + asm volatile ( + "r1 = *(u64 *)(r1 +0); \ + r0 = r1; \ + r2 = 0; \ + r0 += 8; \ + if r1 == 0 goto jmp; \ + r2 = r0; \ + jmp: " + :: + : __clobber_all + ); + return 0; +} + +/* r2 with offset is checked, which won't mark r1 with off=0 as non-NULL */ +SEC("tp_btf/bpf_testmod_test_raw_tp_null") +__success +__log_level(2) +__msg("3: (07) r2 += 8 ; R2_w=trusted_ptr_or_null_sk_buff(id=1,off=8)") +__msg("4: (15) if r2 == 0x0 goto pc+1 ; R2_w=trusted_ptr_or_null_sk_buff(id=1,off=8)") +__msg("5: (bf) r2 = r1 ; R1_w=trusted_ptr_or_null_sk_buff(id=1)") +int BPF_PROG(test_raw_tp_null_copy_check_with_off, struct sk_buff *skb) +{ + asm volatile ( + "r1 = *(u64 *)(r1 +0); \ + r2 = r1; \ + r3 = 0; \ + r2 += 8; \ + if r2 == 0 goto jmp2; \ + r2 = r1; \ + jmp2: " + :: + : __clobber_all + ); + return 0; +} + +/* Ensure state doesn't change for r0 and r1 when performing repeated checks.. */ +SEC("tp_btf/bpf_testmod_test_raw_tp_null") +__success +__log_level(2) +__msg("2: (07) r0 += 8 ; R0_w=trusted_ptr_or_null_sk_buff(id=1,off=8)") +__msg("3: (15) if r0 == 0x0 goto pc+3 ; R0_w=trusted_ptr_or_null_sk_buff(id=1,off=8)") +__msg("4: (15) if r0 == 0x0 goto pc+2 ; R0_w=trusted_ptr_or_null_sk_buff(id=1,off=8)") +__msg("5: (15) if r0 == 0x0 goto pc+1 ; R0_w=trusted_ptr_or_null_sk_buff(id=1,off=8)") +__msg("6: (bf) r2 = r1 ; R1=trusted_ptr_or_null_sk_buff(id=1)") +int BPF_PROG(test_raw_tp_check_with_off, struct sk_buff *skb) +{ + asm volatile ( + "r1 = *(u64 *)(r1 +0); \ + r0 = r1; \ + r0 += 8; \ + if r0 == 0 goto jmp3; \ + if r0 == 0 goto jmp3; \ + if r0 == 0 goto jmp3; \ + r2 = r1; \ + jmp3: " + :: + : __clobber_all + ); + return 0; +} + +char _license[] SEC("license") = "GPL";