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dlfcn: dlerror needs to call free from the base namespace [BZ #24773]

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Calling free directly may end up freeing a pointer allocated by the
dynamic loader using malloc from libc.so in the base namespace using
the allocator from libc.so in a secondary namespace, which results in
crashes.

This commit redirects the free call through GLRO and the dynamic
linker, to reach the correct namespace.  It also cleans up the dlerror
handling along the way, so that pthread_setspecific is no longer
needed (which avoids triggering bug 24774).
This commit is contained in:
Florian Weimer
2021-04-21 19:49:51 +02:00
parent b2964eb1d9
commit fada901819
14 changed files with 335 additions and 235 deletions
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10
malloc/set-freeres.c
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@ -20,6 +20,7 @@
#include <set-hooks.h>
#include <libc-internal.h>
#include <unwind-link.h>
#include <dlfcn/dlerror.h>
#include "../nss/nsswitch.h"
#include "../libio/libioP.h"
@ -28,8 +29,6 @@ DEFINE_HOOK (__libc_subfreeres, (void));
symbol_set_define (__libc_freeres_ptrs);
extern __attribute__ ((weak)) void __libdl_freeres (void);
extern __attribute__ ((weak)) void __libpthread_freeres (void);
void __libc_freeres_fn_section
@ -52,11 +51,6 @@ __libc_freeres (void)
/* We run the resource freeing after IO cleanup. */
RUN_HOOK (__libc_subfreeres, ());
/* Call the libdl list of cleanup functions
(weak-ref-and-check). */
if (&__libdl_freeres != NULL)
__libdl_freeres ();
/* Call the libpthread list of cleanup functions
(weak-ref-and-check). */
if (&__libpthread_freeres != NULL)
@ -66,6 +60,8 @@ __libc_freeres (void)
__libc_unwind_link_freeres ();
#endif
call_function_static_weak (__libc_dlerror_result_free);
for (p = symbol_set_first_element (__libc_freeres_ptrs);
!symbol_set_end_p (__libc_freeres_ptrs, p); ++p)
free (*p);

2
malloc/thread-freeres.c
View File

@ -16,6 +16,7 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <dlfcn/dlerror.h>
#include <libc-internal.h>
#include <malloc-internal.h>
#include <resolv/resolv-internal.h>
@ -36,6 +37,7 @@ __libc_thread_freeres (void)
#endif
call_function_static_weak (__res_thread_freeres);
__glibc_tls_internal_free ();
call_function_static_weak (__libc_dlerror_result_free);
/* This should come last because it shuts down malloc for this
thread and the other shutdown functions might well call free. */