diff options
| author | Andrii Nakryiko <andrii@kernel.org> | 2021-12-10 16:40:43 -0800 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-12-14 15:47:56 +0100 |
| commit | 9fc205b413b3f3e9502fa92151fba63b91230454 (patch) | |
| tree | 9964b204c6a1721168b7041e060df59b5123ce7a /tools/lib/bpf/gen_loader.c | |
| parent | 4581e676d3be9d8c921a48bf18e92c5a8f31bf13 (diff) | |
libbpf: Add sane strncpy alternative and use it internally
strncpy() has a notoriously error-prone semantics which makes GCC
complain about it a lot (and quite often completely completely falsely
at that). Instead of pleasing GCC all the time (-Wno-stringop-truncation
is unfortunately only supported by GCC, so it's a bit too messy to just
enable it in Makefile), add libbpf-internal libbpf_strlcpy() helper
which follows what FreeBSD's strlcpy() does and what most people would
expect from strncpy(): copies up to N-1 first bytes from source string
into destination string and ensures zero-termination afterwards.
Replace all the relevant uses of strncpy/strncat/memcpy in libbpf with
libbpf_strlcpy().
This also fixes the issue reported by Emmanuel Deloget in xsk.c where
memcpy() could access source string beyond its end.
Fixes: 2f6324a3937f8 (libbpf: Support shared umems between queues and devices)
Reported-by: Emmanuel Deloget <emmanuel.deloget@eho.link>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211211004043.2374068-1-andrii@kernel.org
Diffstat (limited to 'tools/lib/bpf/gen_loader.c')
| -rw-r--r-- | tools/lib/bpf/gen_loader.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c index c5859c21d3e9..8ecef1088ba2 100644 --- a/tools/lib/bpf/gen_loader.c +++ b/tools/lib/bpf/gen_loader.c @@ -463,8 +463,7 @@ void bpf_gen__map_create(struct bpf_gen *gen, attr.map_flags = map_attr->map_flags; attr.map_extra = map_attr->map_extra; if (map_name) - memcpy(attr.map_name, map_name, - min((unsigned)strlen(map_name), BPF_OBJ_NAME_LEN - 1)); + libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name)); attr.numa_node = map_attr->numa_node; attr.map_ifindex = map_attr->map_ifindex; attr.max_entries = max_entries; @@ -970,8 +969,7 @@ void bpf_gen__prog_load(struct bpf_gen *gen, core_relos = add_data(gen, gen->core_relos, attr.core_relo_cnt * attr.core_relo_rec_size); - memcpy(attr.prog_name, prog_name, - min((unsigned)strlen(prog_name), BPF_OBJ_NAME_LEN - 1)); + libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name)); prog_load_attr = add_data(gen, &attr, attr_size); /* populate union bpf_attr with a pointer to license */ |