tests: make fuzz-udev-rules work also in the environment created by run_minijail

This should close https://oss-fuzz.com/testcase?key=5642013043589120.

See also https://github.com/google/oss-fuzz/issues/1983.

1 files changed, 18 insertions, 14 deletions

diff --git a/src/fuzz/fuzz-udev-rules.c b/src/fuzz/fuzz-udev-rules.c
index 5889bbe1a8..dbdcda329e 100644
--- a/src/fuzz/fuzz-udev-rules.c
+++ b/src/fuzz/fuzz-udev-rules.c
@@ -16,15 +16,16 @@
 #include "tests.h"
 #include "udev.h"
 
-static const struct fakefs {
+static struct fakefs {
         const char *target;
         bool ignore_mount_error;
+        bool is_mounted;
 } fakefss[] = {
-        { "/sys",                    false },
-        { "/dev",                    false },
-        { "/run",                    false },
-        { "/etc",                    false },
-        { UDEVLIBEXECDIR "/rules.d", true },
+        { "/sys",                    false, false },
+        { "/dev",                    false, false },
+        { "/run",                    false, false },
+        { "/etc",                    false, false },
+        { UDEVLIBEXECDIR "/rules.d", true, false },
 };
 
 static int setup_mount_namespace(void) {
@@ -45,23 +46,30 @@ static int setup_mount_namespace(void) {
 }
 
 static int setup_fake_filesystems(const char *runtime_dir) {
-        for (unsigned i = 0; i < ELEMENTSOF(fakefss); i++)
+        for (unsigned i = 0; i < ELEMENTSOF(fakefss); i++) {
                 if (mount(runtime_dir, fakefss[i].target, NULL, MS_BIND, NULL) < 0) {
                         log_full_errno(fakefss[i].ignore_mount_error ? LOG_DEBUG : LOG_ERR, errno, "Failed to mount %s: %m", fakefss[i].target);
                         if (!fakefss[i].ignore_mount_error)
                                 return -errno;
-                }
+                } else
+                        fakefss[i].is_mounted = true;
+        }
 
         return 0;
 }
 
 static int cleanup_fake_filesystems(const char *runtime_dir) {
-        for (unsigned i = 0; i < ELEMENTSOF(fakefss); i++)
+        for (unsigned i = 0; i < ELEMENTSOF(fakefss); i++) {
+                if (!fakefss[i].is_mounted)
+                        continue;
+
                 if (umount(fakefss[i].target) < 0) {
                         log_full_errno(fakefss[i].ignore_mount_error ? LOG_DEBUG : LOG_ERR, errno, "Failed to umount %s: %m", fakefss[i].target);
                         if (!fakefss[i].ignore_mount_error)
                                 return -errno;
-                }
+                } else
+                        fakefss[i].is_mounted = false;
+        }
         return 0;
 }
 
@@ -70,8 +78,6 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         _cleanup_(rm_rf_physical_and_freep) char *runtime_dir = NULL;
         FILE *f = NULL;
 
-        /* To judge from https://oss-fuzz.com/testcase?key=5642013043589120, unshare/mount can fail.
-         * It isn't critical so let's ignore it for now to see how it goes */
         (void) setup_mount_namespace();
 
         assert_se(runtime_dir = setup_fake_runtime_dir());
@@ -79,8 +85,6 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         if (setup_fake_filesystems(runtime_dir) < 0) {
 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
                 return EXIT_TEST_SKIP;
-#else
-                abort();
 #endif
         }