[glibc/codonell/ld-audit] elf: Fix elf_get_dynamic_info definition

[glibc/codonell/ld-audit] elf: Fix elf_get_dynamic_info definition

[Carlos O'Donell]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ef2c249cbd8ca939b031bca89145e00d6cd47c91

commit ef2c249cbd8ca939b031bca89145e00d6cd47c91
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Mon Oct 11 16:01:49 2021 -0300

    elf: Fix elf_get_dynamic_info definition
    
    Before to 490e6c62aa31a8a ('elf: Avoid nested functions in the loader
    [BZ #27220]'), elf_get_dynamic_info() was defined twice on rtld.c: on
    the first dynamic-link.h include and later within _dl_start().  The
    former definition did not define DONT_USE_BOOTSTRAP_MAP and it is used
    on setup_vdso() (since it is a global definition), while the former does
    define DONT_USE_BOOTSTRAP_MAP and it is used on loader self-relocation.
    
    With the commit change, the function is now included and defined once
    instead of defined as a nested function.  So rtld.c defines without
    defining RTLD_BOOTSTRAP and it brokes at least powerpc32.
    
    This patch fixes by moving the get-dynamic-info.h include out of
    dynamic-link.h, which then the caller can corirectly set the expected
    semantic by defining STATIC_PIE_BOOTSTRAP, RTLD_BOOTSTRAP, and/or
    RESOLVE_MAP.
    
    It also required to enable some asserts only for the loader bootstrap
    to avoid issues when called from setup_vdso().
    
    As a side note, this is another issues with nested functions: it is
    not clear from pre-processed output (-E -dD) how the function will
    be build and its semantic (since nested function will be local and
    extra C defines may change it).
    
    I checked on x86_64-linux-gnu (w/o --enable-static-pie),
    i686-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu-power4,
    aarch64-linux-gnu, arm-linux-gnu, sparc64-linux-gnu, and
    s390x-linux-gnu.
    
    Reviewed-by: Fangrui Song <maskray@google.com>
    (cherry picked from commit 4af6982e4c9fc465ffb7a54b794aaaa134241f05)
    
    Resolved conflicts:
            elf/rtld.c

Diff:
---
 elf/dl-conflict.c           |  1 +
 elf/dl-load.c               |  3 ++-
 elf/dl-reloc-static-pie.c   |  3 ++-
 elf/dl-runtime.c            |  1 +
 elf/dynamic-link.h          |  1 -
 elf/get-dynamic-info.h      | 25 ++++++++++++++-----------
 elf/rtld.c                  |  5 +++--
 elf/setup-vdso.h            |  2 +-
 sysdeps/arm/dl-machine.h    |  1 +
 sysdeps/i386/dl-machine.h   |  1 +
 sysdeps/x86_64/dl-machine.h |  1 +
 11 files changed, 27 insertions(+), 17 deletions(-)

diff --git a/elf/dl-conflict.c b/elf/dl-conflict.c
index 5c8e51d19a..d54356dee3 100644
--- a/elf/dl-conflict.c
+++ b/elf/dl-conflict.c
@@ -17,6 +17,7 @@
    License along with the GNU C Library; see the file COPYING.LIB.  If
    not, see <https://www.gnu.org/licenses/>.  */
 
+#include <assert.h>
 #include <errno.h>
 #include <libintl.h>
 #include <stdlib.h>
diff --git a/elf/dl-load.c b/elf/dl-load.c
index 0976977fbd..eea06629a9 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -58,6 +58,7 @@ struct filebuf
 };
 
 #include "dynamic-link.h"
+#include "get-dynamic-info.h"
 #include <abi-tag.h>
 #include <stackinfo.h>
 #include <sysdep.h>
@@ -1295,7 +1296,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
   if (l->l_ld != 0)
     l->l_ld = (ElfW(Dyn) *) ((ElfW(Addr)) l->l_ld + l->l_addr);
 
-  elf_get_dynamic_info (l);
+  elf_get_dynamic_info (l, false);
 
   /* Make sure we are not dlopen'ing an object that has the
      DF_1_NOOPEN flag set, or a PIE object.  */
diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c
index a52ba8aeb8..f323b4dd0d 100644
--- a/elf/dl-reloc-static-pie.c
+++ b/elf/dl-reloc-static-pie.c
@@ -28,6 +28,7 @@
 #define STATIC_PIE_BOOTSTRAP
 #define RESOLVE_MAP(map, scope, sym, version, flags) map
 #include "dynamic-link.h"
+#include "get-dynamic-info.h"
 
 /* Relocate static executable with PIE.  */
 
@@ -51,7 +52,7 @@ _dl_relocate_static_pie (void)
 	break;
       }
 
-  elf_get_dynamic_info (main_map);
+  elf_get_dynamic_info (main_map, false);
 
 # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
   ELF_MACHINE_BEFORE_RTLD_RELOC (main_map, main_map->l_info);
diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c
index 9d0d941000..61c260ddb8 100644
--- a/elf/dl-runtime.c
+++ b/elf/dl-runtime.c
@@ -19,6 +19,7 @@
 #define IN_DL_RUNTIME 1		/* This can be tested in dl-machine.h.  */
 
 #include <alloca.h>
+#include <assert.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/param.h>
diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h
index 7cc3021164..21cdfc88bb 100644
--- a/elf/dynamic-link.h
+++ b/elf/dynamic-link.h
@@ -93,7 +93,6 @@ elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
 
 #include <dl-machine.h>
 
-#include "get-dynamic-info.h"
 
 #ifdef RESOLVE_MAP
 
diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h
index 15c316b38c..d169099fbc 100644
--- a/elf/get-dynamic-info.h
+++ b/elf/get-dynamic-info.h
@@ -25,7 +25,7 @@
 #include <libc-diag.h>
 
 static inline void __attribute__ ((unused, always_inline))
-elf_get_dynamic_info (struct link_map *l)
+elf_get_dynamic_info (struct link_map *l, bool check)
 {
 #if __ELF_NATIVE_CLASS == 32
   typedef Elf32_Word d_tag_utype;
@@ -112,16 +112,19 @@ elf_get_dynamic_info (struct link_map *l)
     assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
 #endif
 #ifdef RTLD_BOOTSTRAP
-  /* Only the bind now flags are allowed.  */
-  assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
-	  || (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
-  /* Flags must not be set for ld.so.  */
-  assert (info[DT_FLAGS] == NULL
-	  || (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
-#endif
-#if defined RTLD_BOOTSTRAP || defined STATIC_PIE_BOOTSTRAP
-  assert (info[DT_RUNPATH] == NULL);
-  assert (info[DT_RPATH] == NULL);
+  if (check)
+    {
+      /* Only the bind now flags are allowed.  */
+      assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
+	      || (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
+      /* Flags must not be set for ld.so.  */
+      assert (info[DT_FLAGS] == NULL
+	      || (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
+# ifdef STATIC_PIE_BOOTSTRAP
+      assert (info[DT_RUNPATH] == NULL);
+      assert (info[DT_RPATH] == NULL);
+# endif
+    }
 #else
   if (info[DT_FLAGS] != NULL)
     {
diff --git a/elf/rtld.c b/elf/rtld.c
index e5653d8e3c..23207112a1 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -513,6 +513,7 @@ _dl_start_final (void *arg, struct dl_start_final_info *info)
      is trivial: always the map of ld.so itself.  */
 #define RTLD_BOOTSTRAP
 #define RESOLVE_MAP(map, scope, sym, version, flags) map
+#include "get-dynamic-info.h"
 #include "dynamic-link.h"
 
 static ElfW(Addr) __attribute_used__
@@ -548,7 +549,7 @@ _dl_start (void *arg)
   /* Read our own dynamic section and fill in the info array.  */
   bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
   bootstrap_map.l_ld_readonly = DL_RO_DYN_SECTION;
-  elf_get_dynamic_info (&bootstrap_map);
+  elf_get_dynamic_info (&bootstrap_map, true);
 
 #if NO_TLS_OFFSET != 0
   bootstrap_map.l_tls_offset = NO_TLS_OFFSET;
@@ -1616,7 +1617,7 @@ dl_main (const ElfW(Phdr) *phdr,
   if (! rtld_is_main)
     {
       /* Extract the contents of the dynamic section for easy access.  */
-      elf_get_dynamic_info (main_map);
+      elf_get_dynamic_info (main_map, false);
 
       /* If the main map is libc.so, update the base namespace to
 	 refer to this map.  If libc.so is loaded later, this happens
diff --git a/elf/setup-vdso.h b/elf/setup-vdso.h
index f44748bc98..6fdffafcca 100644
--- a/elf/setup-vdso.h
+++ b/elf/setup-vdso.h
@@ -64,7 +64,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
       l->l_map_end += l->l_addr;
       l->l_text_end += l->l_addr;
       l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);
-      elf_get_dynamic_info (l);
+      elf_get_dynamic_info (l, false);
       _dl_setup_hash (l);
       l->l_relocated = 1;
 
diff --git a/sysdeps/arm/dl-machine.h b/sysdeps/arm/dl-machine.h
index 7e6761bbe8..86f866ca7c 100644
--- a/sysdeps/arm/dl-machine.h
+++ b/sysdeps/arm/dl-machine.h
@@ -21,6 +21,7 @@
 
 #define ELF_MACHINE_NAME "ARM"
 
+#include <assert.h>
 #include <sys/param.h>
 #include <tls.h>
 #include <dl-tlsdesc.h>
diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h
index 78ce890c0f..fa902612ca 100644
--- a/sysdeps/i386/dl-machine.h
+++ b/sysdeps/i386/dl-machine.h
@@ -21,6 +21,7 @@
 
 #define ELF_MACHINE_NAME "i386"
 
+#include <assert.h>
 #include <sys/param.h>
 #include <sysdep.h>
 #include <tls.h>
diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h
index d3fcbb37bf..90c77cfea1 100644
--- a/sysdeps/x86_64/dl-machine.h
+++ b/sysdeps/x86_64/dl-machine.h
@@ -22,6 +22,7 @@
 
 #define ELF_MACHINE_NAME "x86_64"
 
+#include <assert.h>
 #include <sys/param.h>
 #include <sysdep.h>
 #include <tls.h>