From: Leo Yan leo.yan@linaro.org
[ Upstream commit 33bae185f74d49a0d7b1bfaafb8e959efce0f243 ]
Based on the following report from Smatch, fix the potential NULL pointer dereference check:
tools/lib/bpf/libbpf.c:3493 bpf_prog_load_xattr() warn: variable dereferenced before check 'attr' (see line 3483)
3479 int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, 3480 struct bpf_object **pobj, int *prog_fd) 3481 { 3482 struct bpf_object_open_attr open_attr = { 3483 .file = attr->file, 3484 .prog_type = attr->prog_type, ^^^^^^ 3485 };
At the head of function, it directly access 'attr' without checking if it's NULL pointer. This patch moves the values assignment after validating 'attr' and 'attr->file'.
Signed-off-by: Leo Yan leo.yan@linaro.org Acked-by: Yonghong Song yhs@fb.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 151f7ac1882e..3865a5d27251 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3487,10 +3487,7 @@ int bpf_prog_load(const char *file, enum bpf_prog_type type, int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, struct bpf_object **pobj, int *prog_fd) { - struct bpf_object_open_attr open_attr = { - .file = attr->file, - .prog_type = attr->prog_type, - }; + struct bpf_object_open_attr open_attr = {}; struct bpf_program *prog, *first_prog = NULL; enum bpf_attach_type expected_attach_type; enum bpf_prog_type prog_type; @@ -3503,6 +3500,9 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, if (!attr->file) return -EINVAL;
+ open_attr.file = attr->file; + open_attr.prog_type = attr->prog_type; + obj = bpf_object__open_xattr(&open_attr); if (IS_ERR_OR_NULL(obj)) return -ENOENT;