ld.so: Replace DL_RO_DYN_SECTION with dl_relocate_ld [BZ #28340]

We can't relocate entries in dynamic section if it is readonly:

1. Add a l_ld_readonly field to struct link_map to indicate if dynamic
section is readonly and set it based on p_flags of PT_DYNAMIC segment.
2. Replace DL_RO_DYN_SECTION with dl_relocate_ld to decide if dynamic
section should be relocated.
3. Remove DL_RO_DYN_TEMP_CNT.
4. Don't use a static dynamic section to make readonly dynamic section
in vDSO writable.
5. Remove the temp argument from elf_get_dynamic_info.

This fixes BZ #28340.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/elf/dl-load.c b/elf/dl-load.c
index 39e0d074b4..6ea71077af 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -1149,6 +1149,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
 		 such a segment to avoid a crash later.  */
 	      l->l_ld = (void *) ph->p_vaddr;
 	      l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
+	      l->l_ld_readonly = (ph->p_flags & PF_W) == 0;
 	    }
 	  break;
 
@@ -1292,7 +1293,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
   else
     l->l_ld = (ElfW(Dyn) *) ((ElfW(Addr)) l->l_ld + l->l_addr);
 
-  elf_get_dynamic_info (l, NULL);
+  elf_get_dynamic_info (l);
 
   /* Make sure we are not dlopen'ing an object that has the
      DF_1_NOOPEN flag set, or a PIE object.  */