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authorFlorian Weimer <fweimer@redhat.com>2017-12-18 20:04:13 +0100
committerFlorian Weimer <fweimer@redhat.com>2017-12-18 20:04:13 +0100
commit8e1472d2c1e25e6eabc2059170731365f6d5b3d1 (patch)
tree5b29308e6b00178a34422b6f7bb7b4f9252801dc /elf/rtld.c
parent49b036bce9f021ae994a85aee8b410d20b29c8b7 (diff)
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ld.so: Examine GLRO to detect inactive loader [BZ #20204]
GLRO (_rtld_global_ro) is read-only after initialization and can
therefore not be patched at run time, unlike the hook table addresses
and their contents, so this is a desirable hardening feature.

The hooks are only needed if ld.so has not been initialized, and this
happens only after static dlopen (dlmopen uses a single ld.so object
across all namespaces).

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'elf/rtld.c')
-rw-r--r--elf/rtld.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/elf/rtld.c b/elf/rtld.c
index cfd3729b8e..c01b7e3641 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -2096,7 +2096,9 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
   GLRO(dl_initial_searchlist) = *GL(dl_ns)[LM_ID_BASE]._ns_main_searchlist;
 
   /* Remember the last search directory added at startup, now that
-     malloc will no longer be the one from dl-minimal.c.  */
+     malloc will no longer be the one from dl-minimal.c.  As a side
+     effect, this marks ld.so as initialized, so that the rtld_active
+     function returns true from now on.  */
   GLRO(dl_init_all_dirs) = GL(dl_all_dirs);
 
   /* Print scope information.  */