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| author | Andrii Nakryiko <andriin@fb.com> | 2019-07-19 12:46:03 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2019-07-19 12:48:55 -0700 |
| commit | 1d4126c4e1190d2f7d3f388552f9bd17ae0c64fc (patch) | |
| tree | 13ec1c89e1f4d94b40ac626d2eb2be5513d5eae8 /tools/lib/bpf/libbpf.c | |
| parent | 04efe5911fb30664a56ec63d272a0f39a71545db (diff) | |
| download | linux-1d4126c4e1190d2f7d3f388552f9bd17ae0c64fc.tar.gz linux-1d4126c4e1190d2f7d3f388552f9bd17ae0c64fc.tar.bz2 linux-1d4126c4e1190d2f7d3f388552f9bd17ae0c64fc.zip | |
libbpf: sanitize VAR to conservative 1-byte INT
If VAR in non-sanitized BTF was size less than 4, converting such VAR
into an INT with size=4 will cause BTF validation failure due to
violationg of STRUCT (into which DATASEC was converted) member size.
Fix by conservatively using size=1.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 87168f21ef43..d8833ff6c4a1 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1377,8 +1377,13 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj) if (!has_datasec && kind == BTF_KIND_VAR) { /* replace VAR with INT */ t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); - t->size = sizeof(int); - *(int *)(t+1) = BTF_INT_ENC(0, 0, 32); + /* + * using size = 1 is the safest choice, 4 will be too + * big and cause kernel BTF validation failure if + * original variable took less than 4 bytes + */ + t->size = 1; + *(int *)(t+1) = BTF_INT_ENC(0, 0, 8); } else if (!has_datasec && kind == BTF_KIND_DATASEC) { /* replace DATASEC with STRUCT */ struct btf_var_secinfo *v = (void *)(t + 1); |