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selftests/bpf: add verifier tests for wide stores 

Make sure that wide stores are allowed at proper (aligned) addresses.
Note that user_ip6 is naturally aligned on 8-byte boundary, so
correct addresses are user_ip6[0] and user_ip6[2]. msg_src_ip6 is,
however, aligned on a 4-byte bondary, so only msg_src_ip6[1]
can be wide-stored.

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Stanislav Fomichev 2019-07-01 10:38:41 -07:00 committed by Daniel Borkmann
parent 4cfacbe6df
commit 76d950773c
2 changed files with 50 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
tools/testing/selftests/bpf/test_verifier.c
View File

@ -105,6 +105,7 @@ struct bpf_test {
__u64 data64[TEST_DATA_LEN / 8];
};
} retvals[MAX_TEST_RUNS];
enum bpf_attach_type expected_attach_type;
};
/* Note we want this to be 64 bit aligned so that the end of our array is
@ -850,6 +851,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
int fd_prog, expected_ret, alignment_prevented_execution;
int prog_len, prog_type = test->prog_type;
struct bpf_insn *prog = test->insns;
struct bpf_load_program_attr attr;
int run_errs, run_successes;
int map_fds[MAX_NR_MAPS];
const char *expected_err;
@ -881,8 +883,17 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
pflags |= BPF_F_STRICT_ALIGNMENT;
if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS)
pflags |= BPF_F_ANY_ALIGNMENT;
fd_prog = bpf_verify_program(prog_type, prog, prog_len, pflags,
"GPL", 0, bpf_vlog, sizeof(bpf_vlog), 4);
memset(&attr, 0, sizeof(attr));
attr.prog_type = prog_type;
attr.expected_attach_type = test->expected_attach_type;
attr.insns = prog;
attr.insns_cnt = prog_len;
attr.license = "GPL";
attr.log_level = 4;
attr.prog_flags = pflags;
fd_prog = bpf_load_program_xattr(&attr, bpf_vlog, sizeof(bpf_vlog));
if (fd_prog < 0 && !bpf_probe_prog_type(prog_type, 0)) {
printf("SKIP (unsupported program type %d)\n", prog_type);
skips++;
@ -912,7 +923,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
printf("FAIL\nUnexpected success to load!\n");
goto fail_log;
}
if (!strstr(bpf_vlog, expected_err)) {
if (!expected_err || !strstr(bpf_vlog, expected_err)) {
printf("FAIL\nUnexpected error message!\n\tEXP: %s\n\tRES: %s\n",
expected_err, bpf_vlog);
goto fail_log;

36
tools/testing/selftests/bpf/verifier/wide_store.c Normal file
View File

@ -0,0 +1,36 @@
#define BPF_SOCK_ADDR(field, off, res, err) \
{ \
"wide store to bpf_sock_addr." #field "[" #off "]", \
.insns = { \
BPF_MOV64_IMM(BPF_REG_0, 1), \
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, \
offsetof(struct bpf_sock_addr, field[off])), \
BPF_EXIT_INSN(), \
}, \
.result = res, \
.prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR, \
.expected_attach_type = BPF_CGROUP_UDP6_SENDMSG, \
.errstr = err, \
}
/* user_ip6[0] is u64 aligned */
BPF_SOCK_ADDR(user_ip6, 0, ACCEPT,
NULL),
BPF_SOCK_ADDR(user_ip6, 1, REJECT,
"invalid bpf_context access off=12 size=8"),
BPF_SOCK_ADDR(user_ip6, 2, ACCEPT,
NULL),
BPF_SOCK_ADDR(user_ip6, 3, REJECT,
"invalid bpf_context access off=20 size=8"),
/* msg_src_ip6[0] is _not_ u64 aligned */
BPF_SOCK_ADDR(msg_src_ip6, 0, REJECT,
"invalid bpf_context access off=44 size=8"),
BPF_SOCK_ADDR(msg_src_ip6, 1, ACCEPT,
NULL),
BPF_SOCK_ADDR(msg_src_ip6, 2, REJECT,
"invalid bpf_context access off=52 size=8"),
BPF_SOCK_ADDR(msg_src_ip6, 3, REJECT,
"invalid bpf_context access off=56 size=8"),
#undef BPF_SOCK_ADDR