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| 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/bpf.c | |
| parent | libbpf: Fix potential uninit memory read (diff) | |
| download | wireguard-linux-9fc205b413b3f3e9502fa92151fba63b91230454.tar.xz wireguard-linux-9fc205b413b3f3e9502fa92151fba63b91230454.zip | |
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/bpf.c')
| -rw-r--r-- | tools/lib/bpf/bpf.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 6b2407e12060..1f84d706eb3e 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -112,7 +112,7 @@ int bpf_map_create(enum bpf_map_type map_type, attr.map_type = map_type; if (map_name) - strncat(attr.map_name, map_name, sizeof(attr.map_name) - 1); + libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name)); attr.key_size = key_size; attr.value_size = value_size; attr.max_entries = max_entries; @@ -271,7 +271,7 @@ int bpf_prog_load_v0_6_0(enum bpf_prog_type prog_type, attr.kern_version = OPTS_GET(opts, kern_version, 0); if (prog_name) - strncat(attr.prog_name, prog_name, sizeof(attr.prog_name) - 1); + libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name)); attr.license = ptr_to_u64(license); if (insn_cnt > UINT_MAX) |