On Thu, 5 Oct 2023 at 17:29, James Carter <jwcart2@xxxxxxxxx> wrote:
>
> On Mon, Aug 14, 2023 at 9:42 AM Christian Göttsche
> <cgzones@xxxxxxxxxxxxxx> wrote:
> >
> > Add a utility around selabel_cmp(3).
> >
> > Can be used by users to compare a pre-compiled fcontext file to an
> > original text-based file context definition file.
> >
> > Can be used for development to verify compilation and parsing of the
> > pre-compiled fcontext format works correctly.
> >
> > Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
> > ---
> > libselinux/utils/.gitignore | 1 +
> > libselinux/utils/selabel_compare.c | 119 +++++++++++++++++++++++++++++
> > 2 files changed, 120 insertions(+)
> > create mode 100644 libselinux/utils/selabel_compare.c
> >
> > diff --git a/libselinux/utils/.gitignore b/libselinux/utils/.gitignore
> > index a92e1e94..4e2dfba8 100644
> > --- a/libselinux/utils/.gitignore
> > +++ b/libselinux/utils/.gitignore
> > @@ -16,6 +16,7 @@ getseuser
> > matchpathcon
> > policyvers
> > sefcontext_compile
> > +selabel_compare
> > selabel_digest
> > selabel_get_digests_all_partial_matches
> > selabel_lookup
> > diff --git a/libselinux/utils/selabel_compare.c b/libselinux/utils/selabel_compare.c
> > new file mode 100644
> > index 00000000..f4325f7e
> > --- /dev/null
> > +++ b/libselinux/utils/selabel_compare.c
> > @@ -0,0 +1,119 @@
> > +#include <getopt.h>
> > +#include <stdio.h>
> > +#include <stdlib.h>
> > +#include <string.h>
> > +
> > +#include <selinux/label.h>
> > +
> > +
> > +static void usage(const char *progname)
> > +{
> > + fprintf(stderr,
> > + "usage: %s [-b backend] [-v] file1 file2\n\n"
> > + "Where:\n\t"
> > + "-b The backend - \"file\", \"media\", \"x\", \"db\" or \"prop\" (defaults to \"file\")\n\t"
> > + "-v Validate entries against loaded policy.\n\t"
> > + "file1/file2 Files containing the specs.\n",
> > + progname);
> > +}
> > +
> > +int main(int argc, char *argv[])
> > +{
> > + unsigned int backend = SELABEL_CTX_FILE;
> > + int opt;
> > + const char *validate = NULL, *file1 = NULL, *file2 = NULL;
> > +
> > + if (argc < 3) {
> > + usage(argv[0]);
> > + return EXIT_FAILURE;
> > + }
> > +
> > + while ((opt = getopt(argc, argv, "b:v")) > 0) {
> > + switch (opt) {
> > + case 'b':
> > + if (!strcasecmp(optarg, "file")) {
> > + backend = SELABEL_CTX_FILE;
> > + } else if (!strcmp(optarg, "media")) {
> > + backend = SELABEL_CTX_MEDIA;
> > + } else if (!strcmp(optarg, "x")) {
> > + backend = SELABEL_CTX_X;
> > + } else if (!strcmp(optarg, "db")) {
> > + backend = SELABEL_CTX_DB;
> > + } else if (!strcmp(optarg, "prop")) {
> > + backend = SELABEL_CTX_ANDROID_PROP;
> > + } else if (!strcmp(optarg, "service")) {
> > + backend = SELABEL_CTX_ANDROID_SERVICE;
> > + } else {
> > + fprintf(stderr, "Unknown backend: %s\n", optarg);
> > + usage(argv[0]);
> > + return EXIT_FAILURE;
> > + }
> > + break;
> > + case 'v':
> > + validate = (char *)1;
> > + break;
> > + default:
> > + usage(argv[0]);
> > + return EXIT_FAILURE;
> > + }
> > + }
> > +
> > + if (argc != optind + 2) {
> > + usage(argv[0]);
> > + return EXIT_FAILURE;
> > + }
> > +
> > + file1 = argv[optind++];
> > + file2 = argv[optind];
> > +
> > + {
>
> To me, having a block like this means that the stuff below should be
> in a helper function.
>
> Everything else looks good.
> Jim
>
I didn't want to split the function to complicate the reasoning by
splitting the control flow, introducing 4 function parameters, and
adding return value handling.
Do you still prefer to split?
(I'll send a v2 regardless for a typo below)
>
> > + struct selabel_handle *hnd1, *hnd2;
> > + const struct selinux_opt selabel_option1[] = {
> > + { SELABEL_OPT_PATH, file1 },
> > + { SELABEL_OPT_VALIDATE, validate }
> > + };
> > + const struct selinux_opt selabel_option2[] = {
> > + { SELABEL_OPT_PATH, file2 },
> > + { SELABEL_OPT_VALIDATE, validate }
> > + };
> > + enum selabel_cmp_result result;
> > +
> > + hnd1 = selabel_open(backend, selabel_option1, 2);
> > + if (!hnd1) {
> > + fprintf(stderr, "ERROR: selabel_open - Could not obtain handle for %s: %m\n", file1);
> > + return EXIT_FAILURE;
> > + }
> > +
> > + hnd2 = selabel_open(backend, selabel_option2, 2);
> > + if (!hnd2) {
> > + fprintf(stderr, "ERROR: selabel_open - Could not obtain handle for %s: %m\n", file2);
> > + selabel_close(hnd1);
> > + return EXIT_FAILURE;
> > + }
> > +
> > + result = selabel_cmp(hnd1, hnd2);
> > +
> > + selabel_close(hnd2);
> > + selabel_close(hnd1);
> > +
> > + switch (result) {
> > + case SELABEL_SUBSET:
> > + printf("spec %s is a subset of spec %s\n", file1, file2);
> > + break;
> > + case SELABEL_EQUAL:
> > + printf("spec %s is equal to spec %s\n", file1, file2);
> > + break;
> > + case SELABEL_SUPERSET:
> > + printf("spec %s is a superset of spec %s\n", file1, file2);
> > + break;
> > + case SELABEL_INCOMPARABLE:
> > + printf("spec %s is uncompareable to spec %s\n", file1, file2);
> > + break;
> > + default:
> > + fprintf(stderr, "ERROR: selabel_cmp - Unexpected result %d\n", result);
> > + return EXIT_FAILURE;
> > + }
> > +
> > + return EXIT_SUCCESS;
> > + }
> > +}
> > --
> > 2.40.1
> >
