Re: [PATCH] bpftool: Fix build with OpenSSL versions older than 3.0

[Quentin Monnet]

On 05/12/2025 14:55, Leo Yan wrote:
> ERR_get_error_all() exists only in OpenSSL 3.0 and later. Older versions
> lack this API, causing build failure:
> 
>   sign.c: In function 'display_openssl_errors':
>   sign.c:40:21: warning: implicit declaration of function 'ERR_get_error_all'; did you mean 'ERR_get_error_line'? [-Wimplicit-function-declaration]
>      40 |         while ((e = ERR_get_error_all(&file, &line, NULL, &data, &flags))) {
>         |                     ^~~~~~~~~~~~~~~~~
>         |                     ERR_get_error_line
>   LINK    /tmp/build/perf/util/bpf_skel/.tmp/bootstrap/bpftool
>   /usr/lib/gcc/x86_64-alpine-linux-musl/11.2.1/../../../../x86_64-alpine-linux-musl/bin/ld: /tmp/build/perf/util/bpf_skel/.tmp/bootstrap/sign.o: in function `display_openssl_errors.constprop.0':
>   sign.c:(.text+0x59): undefined reference to `ERR_get_error_all'
>   collect2: error: ld returned 1 exit status
> 
> Use the deprecated ERR_get_error_line_data() for OpenSSL < 3.0, and keep
> using ERR_get_error_all() when available.
> 
> Fixes: 40863f4d6ef2 ("bpftool: Add support for signing BPF programs")
> Signed-off-by: Leo Yan <leo.yan@xxxxxxx>
> ---
>  tools/bpf/bpftool/sign.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/tools/bpf/bpftool/sign.c b/tools/bpf/bpftool/sign.c
> index b34f74d210e9..c98edd6d1dde 100644
> --- a/tools/bpf/bpftool/sign.c
> +++ b/tools/bpf/bpftool/sign.c
> @@ -37,7 +37,11 @@ static void display_openssl_errors(int l)
>  	int flags;
>  	int line;
>  
> +#if OPENSSL_VERSION_MAJOR >= 3
>  	while ((e = ERR_get_error_all(&file, &line, NULL, &data, &flags))) {
> +#else
> +	while ((e = ERR_get_error_line_data(&file, &line, &data, &flags))) {
> +#endif
>  		ERR_error_string_n(e, buf, sizeof(buf));
>  		if (data && (flags & ERR_TXT_STRING)) {
>  			p_err("OpenSSL %s: %s:%d: %s", buf, file, line, data);


Thanks, but this should be addressed in bpf-next already, see commit
90ae54b4c7ec ("bpftool: Allow bpftool to build with openssl < 3")

Quentin