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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2022-01-24 10:46:17 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2022-02-01 14:49:46 -0300
commit32612615c58b394c3eb09f020f31310797ad3854 (patch)
tree3e6b65aaabd471f79a2179e75bbf64ccd1a6fa04 /elf/sotruss-lib.c
parent254d3d5aef2fd8430c469e1938209ac100ebf132 (diff)
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elf: Issue la_symbind for bind-now (BZ #23734)
The audit symbind callback is not called for binaries built with
-Wl,-z,now or when LD_BIND_NOW=1 is used, nor the PLT tracking callbacks
(plt_enter and plt_exit) since this would change the expected
program semantics (where no PLT is expected) and would have performance
implications (such as for BZ#15533).

LAV_CURRENT is also bumped to indicate the audit ABI change (where
la_symbind flags are set by the loader to indicate no possible PLT
trace).

To handle powerpc64 ELFv1 function descriptor, _dl_audit_symbind
requires to know whether bind-now is used so the symbol value is
updated to function text segment instead of the OPD (for lazy binding
this is done by PPC64_LOAD_FUNCPTR on _dl_runtime_resolve).

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
powerpc64-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'elf/sotruss-lib.c')
-rw-r--r--elf/sotruss-lib.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/elf/sotruss-lib.c b/elf/sotruss-lib.c
index 1077458c9d..a5edd438f9 100644
--- a/elf/sotruss-lib.c
+++ b/elf/sotruss-lib.c
@@ -16,6 +16,7 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#include <err.h>
 #include <error.h>
 #include <fcntl.h>
 #include <stdio.h>
@@ -231,6 +232,12 @@ uintptr_t
 la_symbind (Elf_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 	    uintptr_t *defcook, unsigned int *flags, const char *symname)
 {
+  if (*flags & LA_SYMB_NOPLTENTER)
+    warnx ("cannot trace PLT enter (bind-now enabled)");
+
+  if (do_exit && *flags & LA_SYMB_NOPLTEXIT)
+    warnx ("cannot trace PLT exit (bind-now enabled)");
+
   if (!do_exit)
     *flags = LA_SYMB_NOPLTEXIT;