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author | Florian Weimer <fweimer@redhat.com> | 2017-12-18 20:04:13 +0100 |
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committer | Florian Weimer <fweimer@redhat.com> | 2017-12-18 20:04:13 +0100 |
commit | 8e1472d2c1e25e6eabc2059170731365f6d5b3d1 (patch) | |
tree | 5b29308e6b00178a34422b6f7bb7b4f9252801dc /libio/vtables.c | |
parent | 49b036bce9f021ae994a85aee8b410d20b29c8b7 (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 'libio/vtables.c')
-rw-r--r-- | libio/vtables.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/libio/vtables.c b/libio/vtables.c index 41b48db..4d4afa2 100644 --- a/libio/vtables.c +++ b/libio/vtables.c @@ -19,6 +19,7 @@ #include <dlfcn.h> #include <libioP.h> #include <stdio.h> +#include <ldsodefs.h> #ifdef SHARED @@ -54,7 +55,7 @@ _IO_vtable_check (void) { Dl_info di; struct link_map *l; - if (_dl_open_hook != NULL + if (!rtld_active () || (_dl_addr (_IO_vtable_check, &di, &l, NULL) != 0 && l->l_ns != LM_ID_BASE)) return; |