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| author |   Daniel Xu <dxu@dxuuu.xyz> | 2021-07-28 16:09:21 -0700 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2021-08-07 01:39:15 +0200 |
| commit | c34c338a40e4f3b6f80889cd17fd9281784d1c32 (patch) | |
| tree | 332be058a454d94d772a7213578003e1b07cf776 /tools | |
| parent | libbpf: Fix probe for BPF_PROG_TYPE_CGROUP_SOCKOPT (diff) | |
| download | wireguard-linux-c34c338a40e4f3b6f80889cd17fd9281784d1c32.tar.xz wireguard-linux-c34c338a40e4f3b6f80889cd17fd9281784d1c32.zip | |
libbpf: Do not close un-owned FD 0 on errors
Before this patch, btf_new() was liable to close an arbitrary FD 0 if
BTF parsing failed. This was because:
* btf->fd was initialized to 0 through the calloc()
* btf__free() (in the `done` label) closed any FDs >= 0
* btf->fd is left at 0 if parsing fails
This issue was discovered on a system using libbpf v0.3 (without
BTF_KIND_FLOAT support) but with a kernel that had BTF_KIND_FLOAT types
in BTF. Thus, parsing fails.
While this patch technically doesn't fix any issues b/c upstream libbpf
has BTF_KIND_FLOAT support, it'll help prevent issues in the future if
more BTF types are added. It also allow the fix to be backported to
older libbpf's.
Fixes: 3289959b97ca ("libbpf: Support BTF loading and raw data output in both endianness")
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/5969bb991adedb03c6ae93e051fd2a00d293cf25.1627513670.git.dxu@dxuuu.xyz
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/lib/bpf/btf.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index b46760b93bb4..7ff3d5ce44f9 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -804,6 +804,7 @@ static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf) btf->nr_types = 0; btf->start_id = 1; btf->start_str_off = 0; + btf->fd = -1; if (base_btf) { btf->base_btf = base_btf; @@ -832,8 +833,6 @@ static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf) if (err) goto done; - btf->fd = -1; - done: if (err) { btf__free(btf); |