elf: Properly handle zero DT_RELA/DT_REL values

With DT_RELR, there may be no relocations in DT_RELA/DT_REL and their
entry values are zero.  Don't relocate DT_RELA/DT_REL and update the
combined relocation start address if their entry values are zero.

diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h
index 019088f..debbb8c 100644 (file)
--- a/elf/dynamic-link.h
+++ b/elf/dynamic-link.h
@@ -84,7 +84,9 @@ elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
             __typeof (((ElfW(Dyn) *) 0)->d_un.d_val) nrelative; int lazy; }  \
       ranges[2] = { { 0, 0, 0, 0 }, { 0, 0, 0, 0 } };                        \
                                                                              \
-    if ((map)->l_info[DT_##RELOC])                                           \
+    /* With DT_RELR, DT_RELA/DT_REL can have zero value.  */                 \
+    if ((map)->l_info[DT_##RELOC] != NULL                                    \
+       && (map)->l_info[DT_##RELOC]->d_un.d_ptr != 0)                        \
       {                                                                              \
        ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]);                  \
        ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val;           \
@@ -98,6 +100,8 @@ elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
        ElfW(Addr) start = D_PTR ((map), l_info[DT_JMPREL]);                  \
        ElfW(Addr) size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val;             \
                                                                              \
+       if (ranges[0].start == 0)                                             \
+         ranges[0].start = start;                                            \
        if (ranges[0].start + ranges[0].size == (start + size))               \
          ranges[0].size -= size;                                             \
        if (!(do_lazy)                                                        \

diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h
index 6c2a3a1..0314baf 100644 (file)
--- a/elf/get-dynamic-info.h
+++ b/elf/get-dynamic-info.h
@@ -75,24 +75,36 @@ elf_get_dynamic_info (struct link_map *l, bool bootstrap,
 
 # define ADJUST_DYN_INFO(tag) \
       do                                                                     \
-       if (info[tag] != NULL)                                                \
-         info[tag]->d_un.d_ptr += l_addr;                                    \
+       {                                                                     \
+         if (info[tag] != NULL)                                              \
+         info[tag]->d_un.d_ptr += l_addr;                                    \
+       }                                                                     \
       while (0)
 
       ADJUST_DYN_INFO (DT_HASH);
       ADJUST_DYN_INFO (DT_PLTGOT);
       ADJUST_DYN_INFO (DT_STRTAB);
       ADJUST_DYN_INFO (DT_SYMTAB);
+      ADJUST_DYN_INFO (DT_RELR);
+      ADJUST_DYN_INFO (DT_JMPREL);
+      ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
+      ADJUST_DYN_INFO (ADDRIDX (DT_GNU_HASH));
+# undef ADJUST_DYN_INFO
+
+      /* DT_RELA/DT_REL are mandatory.  But they may have zero value if
+        there is DT_RELR.  Don't relocate them if they are zero.  */
+# define ADJUST_DYN_INFO(tag) \
+      do                                                                     \
+       if (info[tag] != NULL && info[tag]->d_un.d_ptr != 0)                  \
+         info[tag]->d_un.d_ptr += l_addr;                                    \
+      while (0)
+
 # if ! ELF_MACHINE_NO_RELA
       ADJUST_DYN_INFO (DT_RELA);
 # endif
 # if ! ELF_MACHINE_NO_REL
       ADJUST_DYN_INFO (DT_REL);
 # endif
-      ADJUST_DYN_INFO (DT_RELR);
-      ADJUST_DYN_INFO (DT_JMPREL);
-      ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
-      ADJUST_DYN_INFO (ADDRIDX (DT_GNU_HASH));
 # undef ADJUST_DYN_INFO
     }
   if (info[DT_PLTREL] != NULL)