diff mbox series

[v4,05/14] elf: Eliminate second loop in find_version in dl-version.c

Message ID 7a0383ffaa70e504c402b94a08d66424b45be1f3.1738530302.git.fweimer@redhat.com (mailing list archive)
State New
Headers
Series RELRO link maps |

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Context Check Description
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Commit Message

Florian Weimer Feb. 2, 2025, 9:13 p.m. UTC 
  The first loop iterates through all objects in the namespace
because _dl_check_map_versions is called after the loaded
objects have been added to the list.  (This list is not limited
by symbol search scope.)

Turn the assert in _dl_check_map_versions into a proper error
because it can be triggered by inconsistent variants of shared
objects.  This assert could fail if the soname in the vn_file field
of the verneed structure for a version is not among the DT_NEEDED
dependencies of an object.  With such a discrepancy, the no matching
object might be loaded, hence the assertion failure.  Current
binutils ld does not seem to produce such objects, preferring to
create unversioned symbols instead of lifting symbol versions from
indirect dependencies of the objects listed on the command line.
This is why there is no test case for this error.
---
 elf/dl-version.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)
diff mbox series

Patch

diff --git a/elf/dl-version.c b/elf/dl-version.c
index d414bd1e18..0fae561e55 100644
--- a/elf/dl-version.c
+++ b/elf/dl-version.c
@@ -31,21 +31,17 @@  __attribute ((always_inline))
 find_needed (const char *name, struct link_map *map)
 {
   struct link_map *tmap;
-  unsigned int n;
 
   for (tmap = GL(dl_ns)[map->l_ns]._ns_loaded; tmap != NULL;
        tmap = tmap->l_next)
     if (_dl_name_match_p (name, tmap))
       return tmap;
 
-  /* The required object is not in the global scope, look to see if it is
-     a dependency of the current object.  */
-  for (n = 0; n < map->l_searchlist.r_nlist; n++)
-    if (_dl_name_match_p (name, map->l_searchlist.r_list[n]))
-      return map->l_searchlist.r_list[n];
-
-  /* Should never happen.  */
-  return NULL;
+  struct dl_exception exception;
+  _dl_exception_create_format
+    (&exception, DSO_FILENAME (map->l_name),
+     "missing soname %s in version dependency", name);
+  _dl_signal_exception (0, &exception, NULL);
 }
 
 
@@ -199,10 +195,6 @@  _dl_check_map_versions (struct link_map *map, int verbose, int trace_mode)
 	  ElfW(Vernaux) *aux;
 	  struct link_map *needed = find_needed (strtab + ent->vn_file, map);
 
-	  /* If NEEDED is NULL this means a dependency was not found
-	     and no stub entry was created.  This should never happen.  */
-	  assert (needed != NULL);
-
 	  /* Make sure this is no stub we created because of a missing
 	     dependency.  */
 	  if (__builtin_expect (! trace_mode, 1)