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-rw-r--r--include/uapi/linux/bpf.h14
-rw-r--r--kernel/bpf/syscall.c7
-rw-r--r--kernel/bpf/verifier.c2
-rw-r--r--tools/include/uapi/linux/bpf.h14
-rw-r--r--tools/lib/bpf/bpf.c8
-rw-r--r--tools/lib/bpf/bpf.h2
-rw-r--r--tools/testing/selftests/bpf/test_align.c4
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c3
8 files changed, 45 insertions, 9 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 597afdbc1ab9..8050caea7495 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -232,6 +232,20 @@ enum bpf_attach_type {
*/
#define BPF_F_STRICT_ALIGNMENT (1U << 0)
+/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
+ * verifier will allow any alignment whatsoever. On platforms
+ * with strict alignment requirements for loads ands stores (such
+ * as sparc and mips) the verifier validates that all loads and
+ * stores provably follow this requirement. This flag turns that
+ * checking and enforcement off.
+ *
+ * It is mostly used for testing when we want to validate the
+ * context and memory access aspects of the verifier, but because
+ * of an unaligned access the alignment check would trigger before
+ * the one we are interested in.
+ */
+#define BPF_F_ANY_ALIGNMENT (1U << 1)
+
/* when bpf_ldimm64->src_reg == BPF_PSEUDO_MAP_FD, bpf_ldimm64->imm == fd */
#define BPF_PSEUDO_MAP_FD 1
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 85cbeec06e50..f9554d9a14e1 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1452,9 +1452,14 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
if (CHECK_ATTR(BPF_PROG_LOAD))
return -EINVAL;
- if (attr->prog_flags & ~BPF_F_STRICT_ALIGNMENT)
+ if (attr->prog_flags & ~(BPF_F_STRICT_ALIGNMENT | BPF_F_ANY_ALIGNMENT))
return -EINVAL;
+ if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) &&
+ (attr->prog_flags & BPF_F_ANY_ALIGNMENT) &&
+ !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
/* copy eBPF program license from user space */
if (strncpy_from_user(license, u64_to_user_ptr(attr->license),
sizeof(license) - 1) < 0)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9584438fa2cc..71988337ac14 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6505,6 +6505,8 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);
if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
env->strict_alignment = true;
+ if (attr->prog_flags & BPF_F_ANY_ALIGNMENT)
+ env->strict_alignment = false;
ret = replace_map_fd_with_map_ptr(env);
if (ret < 0)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 597afdbc1ab9..8050caea7495 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -232,6 +232,20 @@ enum bpf_attach_type {
*/
#define BPF_F_STRICT_ALIGNMENT (1U << 0)
+/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
+ * verifier will allow any alignment whatsoever. On platforms
+ * with strict alignment requirements for loads ands stores (such
+ * as sparc and mips) the verifier validates that all loads and
+ * stores provably follow this requirement. This flag turns that
+ * checking and enforcement off.
+ *
+ * It is mostly used for testing when we want to validate the
+ * context and memory access aspects of the verifier, but because
+ * of an unaligned access the alignment check would trigger before
+ * the one we are interested in.
+ */
+#define BPF_F_ANY_ALIGNMENT (1U << 1)
+
/* when bpf_ldimm64->src_reg == BPF_PSEUDO_MAP_FD, bpf_ldimm64->imm == fd */
#define BPF_PSEUDO_MAP_FD 1
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index ce1822194590..c19226cccf39 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -279,9 +279,9 @@ int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
}
int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
- size_t insns_cnt, int strict_alignment,
- const char *license, __u32 kern_version,
- char *log_buf, size_t log_buf_sz, int log_level)
+ size_t insns_cnt, __u32 prog_flags, const char *license,
+ __u32 kern_version, char *log_buf, size_t log_buf_sz,
+ int log_level)
{
union bpf_attr attr;
@@ -295,7 +295,7 @@ int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
attr.log_level = log_level;
log_buf[0] = 0;
attr.kern_version = kern_version;
- attr.prog_flags = strict_alignment ? BPF_F_STRICT_ALIGNMENT : 0;
+ attr.prog_flags = prog_flags;
return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 09e8bbe111d4..60392b70587c 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -98,7 +98,7 @@ LIBBPF_API int bpf_load_program(enum bpf_prog_type type,
char *log_buf, size_t log_buf_sz);
LIBBPF_API int bpf_verify_program(enum bpf_prog_type type,
const struct bpf_insn *insns,
- size_t insns_cnt, int strict_alignment,
+ size_t insns_cnt, __u32 prog_flags,
const char *license, __u32 kern_version,
char *log_buf, size_t log_buf_sz,
int log_level);
diff --git a/tools/testing/selftests/bpf/test_align.c b/tools/testing/selftests/bpf/test_align.c
index 5f377ec53f2f..3c789d03b629 100644
--- a/tools/testing/selftests/bpf/test_align.c
+++ b/tools/testing/selftests/bpf/test_align.c
@@ -620,8 +620,8 @@ static int do_test_single(struct bpf_align_test *test)
prog_len = probe_filter_length(prog);
fd_prog = bpf_verify_program(prog_type ? : BPF_PROG_TYPE_SOCKET_FILTER,
- prog, prog_len, 1, "GPL", 0,
- bpf_vlog, sizeof(bpf_vlog), 2);
+ prog, prog_len, BPF_F_STRICT_ALIGNMENT,
+ "GPL", 0, bpf_vlog, sizeof(bpf_vlog), 2);
if (fd_prog < 0 && test->result != REJECT) {
printf("Failed to load program.\n");
printf("%s", bpf_vlog);
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 5eace1f606fb..78e779c35869 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -14275,7 +14275,8 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
prog_len = probe_filter_length(prog);
fd_prog = bpf_verify_program(prog_type, prog, prog_len,
- test->flags & F_LOAD_WITH_STRICT_ALIGNMENT,
+ test->flags & F_LOAD_WITH_STRICT_ALIGNMENT ?
+ BPF_F_STRICT_ALIGNMENT : 0,
"GPL", 0, bpf_vlog, sizeof(bpf_vlog), 1);
expected_ret = unpriv && test->result_unpriv != UNDEF ?
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.