bootspec: fix null-dereference-read

Fixes [oss-fuzz#53578](https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=53578).
Fixes #25450.

diff --git a/src/shared/bootspec.c b/src/shared/bootspec.c
index 56274a0d4d35ab200daf451cda411e46cb3051ed..83960b99d3fdd3c1f676bd8cb62d0ab9755b2887 100644 (file)
--- a/src/shared/bootspec.c
+++ b/src/shared/bootspec.c
@@ -980,6 +980,8 @@ static int boot_config_find(const BootConfig *config, const char *id) {
         if (id[0] == '@') {
                 if (!strcaseeq(id, "@saved"))
                         return -1;
+                if (!config->entry_selected)
+                        return -1;
                 id = config->entry_selected;
         }
 

diff --git a/test/fuzz/fuzz-bootspec/clusterfuzz-testcase-minimized-fuzz-bootspec-5731869371269120 b/test/fuzz/fuzz-bootspec/clusterfuzz-testcase-minimized-fuzz-bootspec-5731869371269120
new file mode 100644 (file)
index 0000000..8804abd
--- /dev/null
+++ b/test/fuzz/fuzz-bootspec/clusterfuzz-testcase-minimized-fuzz-bootspec-5731869371269120
@@ -0,0 +1 @@
+{"config":"default @saved","loader":[""]}
\ No newline at end of file