From: Andrei Matei andreimatei1@gmail.com
mainline inclusion from mainline-5.11-rc1 commit 80b2b5c3a701d56de98d00d99bc9cc384fb316d9 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Before this patch, a program with unspecified type (BPF_PROG_TYPE_UNSPEC) would be passed to the BPF syscall, only to have the kernel reject it with an opaque invalid argument error. This patch makes libbpf reject such programs with a nicer error message - in particular libbpf now tries to diagnose bad ELF section names at both open time and load time.
Signed-off-by: Andrei Matei andreimatei1@gmail.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20201203043410.59699-1-andreimatei1@gmail.com (cherry picked from commit 80b2b5c3a701d56de98d00d99bc9cc384fb316d9) Signed-off-by: Wang Yufen wangyufen@huawei.com --- tools/lib/bpf/libbpf.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2894d837e9f8..76c65fd7206c 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6687,6 +6687,16 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, char *log_buf = NULL; int btf_fd, ret;
+ if (prog->type == BPF_PROG_TYPE_UNSPEC) { + /* + * The program type must be set. Most likely we couldn't find a proper + * section definition at load time, and thus we didn't infer the type. + */ + pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n", + prog->name, prog->sec_name); + return -EINVAL; + } + if (!insns || !insns_cnt) return -EINVAL;
@@ -6982,9 +6992,12 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
bpf_object__for_each_program(prog, obj) { prog->sec_def = find_sec_def(prog->sec_name); - if (!prog->sec_def) + if (!prog->sec_def) { /* couldn't guess, but user might manually specify */ + pr_debug("prog '%s': unrecognized ELF section name '%s'\n", + prog->name, prog->sec_name); continue; + }
if (prog->sec_def->is_sleepable) prog->prog_flags |= BPF_F_SLEEPABLE;