Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2023-06-21

We've added 7 non-merge commits during the last 14 day(s) which contain
a total of 7 files changed, 181 insertions(+), 15 deletions(-).

The main changes are:

1) Fix a verifier id tracking issue with scalars upon spill,
   from Maxim Mikityanskiy.

2) Fix NULL dereference if an exception is generated while a BPF
   subprogram is running, from Krister Johansen.

3) Fix a BTF verification failure when compiling kernel with LLVM_IAS=0,
   from Florent Revest.

4) Fix expected_attach_type enforcement for kprobe_multi link,
   from Jiri Olsa.

5) Fix a bpf_jit_dump issue for x86_64 to pick the correct JITed image,
   from Yonghong Song.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Force kprobe multi expected_attach_type for kprobe_multi link
  bpf/btf: Accept function names that contain dots
  selftests/bpf: add a test for subprogram extables
  bpf: ensure main program has an extable
  bpf: Fix a bpf_jit_dump issue for x86_64 with sysctl bpf_jit_enable.
  selftests/bpf: Add test cases to assert proper ID tracking on spill
  bpf: Fix verifier id tracking of scalars on spill
====================

Link: https://lore.kernel.org/r/20230621101116.16122-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 159 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/subprogs_extable.c b/tools/testing/selftests/bpf/prog_tests/subprogs_extable.c
new file mode 100644
index 000000000000..3afd9f775f68
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/subprogs_extable.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include "test_subprogs_extable.skel.h"
+
+void test_subprogs_extable(void)
+{
+	const int read_sz = 456;
+	struct test_subprogs_extable *skel;
+	int err;
+
+	skel = test_subprogs_extable__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+		return;
+
+	err = test_subprogs_extable__attach(skel);
+	if (!ASSERT_OK(err, "skel_attach"))
+		goto cleanup;
+
+	/* trigger tracepoint */
+	ASSERT_OK(trigger_module_test_read(read_sz), "trigger_read");
+
+	ASSERT_NEQ(skel->bss->triggered, 0, "verify at least one program ran");
+
+	test_subprogs_extable__detach(skel);
+
+cleanup:
+	test_subprogs_extable__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_subprogs_extable.c b/tools/testing/selftests/bpf/progs/test_subprogs_extable.c
new file mode 100644
index 000000000000..e2a21fbd4e44
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_subprogs_extable.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 8);
+	__type(key, __u32);
+	__type(value, __u64);
+} test_array SEC(".maps");
+
+unsigned int triggered;
+
+static __u64 test_cb(struct bpf_map *map, __u32 *key, __u64 *val, void *data)
+{
+	return 1;
+}
+
+SEC("fexit/bpf_testmod_return_ptr")
+int BPF_PROG(handle_fexit_ret_subprogs, int arg, struct file *ret)
+{
+	*(volatile long *)ret;
+	*(volatile int *)&ret->f_mode;
+	bpf_for_each_map_elem(&test_array, test_cb, NULL, 0);
+	triggered++;
+	return 0;
+}
+
+SEC("fexit/bpf_testmod_return_ptr")
+int BPF_PROG(handle_fexit_ret_subprogs2, int arg, struct file *ret)
+{
+	*(volatile long *)ret;
+	*(volatile int *)&ret->f_mode;
+	bpf_for_each_map_elem(&test_array, test_cb, NULL, 0);
+	triggered++;
+	return 0;
+}
+
+SEC("fexit/bpf_testmod_return_ptr")
+int BPF_PROG(handle_fexit_ret_subprogs3, int arg, struct file *ret)
+{
+	*(volatile long *)ret;
+	*(volatile int *)&ret->f_mode;
+	bpf_for_each_map_elem(&test_array, test_cb, NULL, 0);
+	triggered++;
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c
index 136e5530b72c..6115520154e3 100644
--- a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c
+++ b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c
@@ -371,4 +371,83 @@ __naked void and_then_at_fp_8(void)
 "	::: __clobber_all);
 }
 
+SEC("xdp")
+__description("32-bit spill of 64-bit reg should clear ID")
+__failure __msg("math between ctx pointer and 4294967295 is not allowed")
+__naked void spill_32bit_of_64bit_fail(void)
+{
+	asm volatile ("					\
+	r6 = r1;					\
+	/* Roll one bit to force the verifier to track both branches. */\
+	call %[bpf_get_prandom_u32];			\
+	r0 &= 0x8;					\
+	/* Put a large number into r1. */		\
+	r1 = 0xffffffff;				\
+	r1 <<= 32;					\
+	r1 += r0;					\
+	/* Assign an ID to r1. */			\
+	r2 = r1;					\
+	/* 32-bit spill r1 to stack - should clear the ID! */\
+	*(u32*)(r10 - 8) = r1;				\
+	/* 32-bit fill r2 from stack. */		\
+	r2 = *(u32*)(r10 - 8);				\
+	/* Compare r2 with another register to trigger find_equal_scalars.\
+	 * Having one random bit is important here, otherwise the verifier cuts\
+	 * the corners. If the ID was mistakenly preserved on spill, this would\
+	 * cause the verifier to think that r1 is also equal to zero in one of\
+	 * the branches, and equal to eight on the other branch.\
+	 */						\
+	r3 = 0;						\
+	if r2 != r3 goto l0_%=;				\
+l0_%=:	r1 >>= 32;					\
+	/* At this point, if the verifier thinks that r1 is 0, an out-of-bounds\
+	 * read will happen, because it actually contains 0xffffffff.\
+	 */						\
+	r6 += r1;					\
+	r0 = *(u32*)(r6 + 0);				\
+	exit;						\
+"	:
+	: __imm(bpf_get_prandom_u32)
+	: __clobber_all);
+}
+
+SEC("xdp")
+__description("16-bit spill of 32-bit reg should clear ID")
+__failure __msg("dereference of modified ctx ptr R6 off=65535 disallowed")
+__naked void spill_16bit_of_32bit_fail(void)
+{
+	asm volatile ("					\
+	r6 = r1;					\
+	/* Roll one bit to force the verifier to track both branches. */\
+	call %[bpf_get_prandom_u32];			\
+	r0 &= 0x8;					\
+	/* Put a large number into r1. */		\
+	w1 = 0xffff0000;				\
+	r1 += r0;					\
+	/* Assign an ID to r1. */			\
+	r2 = r1;					\
+	/* 16-bit spill r1 to stack - should clear the ID! */\
+	*(u16*)(r10 - 8) = r1;				\
+	/* 16-bit fill r2 from stack. */		\
+	r2 = *(u16*)(r10 - 8);				\
+	/* Compare r2 with another register to trigger find_equal_scalars.\
+	 * Having one random bit is important here, otherwise the verifier cuts\
+	 * the corners. If the ID was mistakenly preserved on spill, this would\
+	 * cause the verifier to think that r1 is also equal to zero in one of\
+	 * the branches, and equal to eight on the other branch.\
+	 */						\
+	r3 = 0;						\
+	if r2 != r3 goto l0_%=;				\
+l0_%=:	r1 >>= 16;					\
+	/* At this point, if the verifier thinks that r1 is 0, an out-of-bounds\
+	 * read will happen, because it actually contains 0xffff.\
+	 */						\
+	r6 += r1;					\
+	r0 = *(u32*)(r6 + 0);				\
+	exit;						\
+"	:
+	: __imm(bpf_get_prandom_u32)
+	: __clobber_all);
+}
+
 char _license[] SEC("license") = "GPL";