[glibc] elf: _dl_find_object may return 1 during early startup (bug 30515)

[glibc] elf: _dl_find_object may return 1 during early startup (bug 30515)

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=1bcfe0f732066ae5336b252295591ebe7e51c301

commit 1bcfe0f732066ae5336b252295591ebe7e51c301
Author: Florian Weimer <fweimer@redhat.com>
Date:   Fri Jul 7 10:11:26 2023 +0200

    elf: _dl_find_object may return 1 during early startup (bug 30515)
    
    Success is reported with a 0 return value, and failure is -1.
    Enhance the kitchen sink test elf/tst-audit28 to cover
    _dl_find_object as well.
    
    Fixes commit 5d28a8962dcb ("elf: Add _dl_find_object function")
    and bug 30515.
    
    Reviewed-by: Carlos O'Donell <carlos@redhat.com>
    Tested-by: Carlos O'Donell <carlos@redhat.com>

Diff:
---
 elf/dl-find_object.c |  2 +-
 elf/tst-auditmod28.c | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/elf/dl-find_object.c b/elf/dl-find_object.c
index 928eb499cc..c1390ee10f 100644
--- a/elf/dl-find_object.c
+++ b/elf/dl-find_object.c
@@ -46,7 +46,7 @@ _dl_find_object_slow (void *pc, struct dl_find_object *result)
           struct dl_find_object_internal internal;
           _dl_find_object_from_map (l, &internal);
           _dl_find_object_to_external (&internal, result);
-          return 1;
+          return 0;
         }
 
   /* Object not found.  */
diff --git a/elf/tst-auditmod28.c b/elf/tst-auditmod28.c
index f6ab991398..f6dfbbe202 100644
--- a/elf/tst-auditmod28.c
+++ b/elf/tst-auditmod28.c
@@ -71,6 +71,17 @@ la_version (unsigned int current)
   TEST_VERIFY (dladdr1 (&_exit, &info, &extra_info, RTLD_DL_LINKMAP) != 0);
   TEST_VERIFY (extra_info == handle);
 
+  /* Check _dl_find_object.  */
+  struct dl_find_object dlfo;
+  TEST_COMPARE (_dl_find_object (__builtin_return_address (0), &dlfo), 0);
+  /* "ld.so" is seen with --enable-hardcoded-path-in-tests.  */
+  if (strcmp (basename (dlfo.dlfo_link_map->l_name), "ld.so") != 0)
+    TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LD_SO);
+  TEST_COMPARE (_dl_find_object (dlsym (handle, "environ"), &dlfo), 0);
+  TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LIBC_SO);
+  TEST_COMPARE (_dl_find_object ((void *) 1, &dlfo), -1);
+  TEST_COMPARE (_dl_find_object ((void *) -1, &dlfo), -1);
+
   /* Verify that dlmopen creates a new namespace.  */
   void *dlmopen_handle = xdlmopen (LM_ID_NEWLM, LIBC_SO, RTLD_NOW);
   TEST_VERIFY (dlmopen_handle != handle);