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From: Roberto Sassu <roberto.sassu@huaweicloud.com>
To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
	martin.lau@linux.dev, song@kernel.org, yhs@fb.com,
	john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
	haoluo@google.com, jolsa@kernel.org, mykolal@fb.com,
	revest@chromium.org, jackmanb@chromium.org, shuah@kernel.org,
	paul@paul-moore.com, casey@schaufler-ca.com, zohar@linux.ibm.com
Cc: bpf@vger.kernel.org, linux-security-module@vger.kernel.org,
	linux-integrity@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-kernel@vger.kernel.org, nicolas.bouchinet@clip-os.org
Subject: [RESEND][RFC][PATCH 3/3] selftests/bpf: Check if return values of LSM programs are allowed
Date: Fri, 28 Oct 2022 18:54:23 +0200	[thread overview]
Message-ID: <20221028165423.386151-3-roberto.sassu@huaweicloud.com> (raw)
In-Reply-To: <20221028165423.386151-1-roberto.sassu@huaweicloud.com>

From: Roberto Sassu <roberto.sassu@huawei.com>

Ensure that the eBPF verifier allows to load only LSM programs that return
an allowed value depending on the LSM hook they attach to.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 .../testing/selftests/bpf/verifier/lsm_ret.c  | 148 ++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/verifier/lsm_ret.c

diff --git a/tools/testing/selftests/bpf/verifier/lsm_ret.c b/tools/testing/selftests/bpf/verifier/lsm_ret.c
new file mode 100644
index 000000000000..1a11f47fb24a
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/lsm_ret.c
@@ -0,0 +1,148 @@
+{
+	"lsm return value: positive not allowed, return -EPERM",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, -EPERM),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "inode_permission",
+	.expected_attach_type = BPF_LSM_MAC,
+	.result = ACCEPT,
+},
+{
+	"lsm return value: positive not allowed, return zero",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "inode_permission",
+	.expected_attach_type = BPF_LSM_MAC,
+	.result = ACCEPT,
+},
+{
+	"lsm return value: positive not allowed, return one",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "inode_permission",
+	.expected_attach_type = BPF_LSM_MAC,
+	.errstr = "Invalid R0, cannot return positive value",
+	.result = REJECT,
+},
+{
+	"lsm return value: zero/positive not allowed, return -EPERM",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, -EPERM),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "inode_init_security",
+	.expected_attach_type = BPF_LSM_MAC,
+	.result = ACCEPT,
+},
+{
+	"lsm return value: zero/positive not allowed, return zero",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "inode_init_security",
+	.expected_attach_type = BPF_LSM_MAC,
+	.errstr = "Invalid R0, cannot return zero value",
+	.result = REJECT,
+},
+{
+	"lsm return value: zero/positive not allowed, return one",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "inode_init_security",
+	.expected_attach_type = BPF_LSM_MAC,
+	.errstr = "Invalid R0, cannot return positive value",
+	.result = REJECT,
+},
+{
+	"lsm return value: positive allowed, return one",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "getprocattr",
+	.expected_attach_type = BPF_LSM_MAC,
+	.result = ACCEPT,
+},
+{
+	"lsm return value: positive allowed, return two",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "getprocattr",
+	.expected_attach_type = BPF_LSM_MAC,
+	.result = ACCEPT,
+},
+{
+	"lsm return value: only one allowed, return one",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "audit_rule_match",
+	.expected_attach_type = BPF_LSM_MAC,
+	.result = ACCEPT,
+},
+{
+	"lsm return value: only one allowed, return two",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "audit_rule_match",
+	.expected_attach_type = BPF_LSM_MAC,
+	.errstr = "Invalid R0, can return only one as positive value",
+	.result = REJECT,
+},
+{
+	"lsm return value: negative not allowed, return -EPERM",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, -EPERM),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "vm_enough_memory",
+	.expected_attach_type = BPF_LSM_MAC,
+	.errstr = "Invalid R0, cannot return negative value",
+	.result = REJECT,
+},
+{
+	"lsm return value: negative not allowed, return zero",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "vm_enough_memory",
+	.expected_attach_type = BPF_LSM_MAC,
+	.result = ACCEPT,
+},
+{
+	"lsm return value: negative not allowed, return one",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_LSM,
+	.kfunc = "vm_enough_memory",
+	.expected_attach_type = BPF_LSM_MAC,
+	.result = ACCEPT,
+},
-- 
2.25.1


  parent reply	other threads:[~2022-10-28 16:56 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-28 16:54 [RESEND][RFC][PATCH 1/3] lsm: Clarify documentation of vm_enough_memory hook Roberto Sassu
2022-10-28 16:54 ` [RESEND][RFC][PATCH 2/3] bpf-lsm: Limit values that can be returned by security modules Roberto Sassu
2022-11-03 15:09   ` KP Singh
2022-11-04 15:28     ` Roberto Sassu
2022-11-05  0:42       ` Alexei Starovoitov
2022-11-07 12:32         ` Roberto Sassu
2022-11-07 16:00           ` Alexei Starovoitov
2022-11-07 16:19             ` Roberto Sassu
2022-10-28 16:54 ` Roberto Sassu [this message]
2022-11-03 15:11 ` [RESEND][RFC][PATCH 1/3] lsm: Clarify documentation of vm_enough_memory hook KP Singh

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