fada901819
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).
93 lines
2.9 KiB
C
93 lines
2.9 KiB
C
/* Memory management for dlerror messages.
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Copyright (C) 2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _DLERROR_H
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#define _DLERROR_H
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#include <dlfcn.h>
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#include <ldsodefs.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdlib.h>
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/* Source of the errstring member in struct dl_action_result, for
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finding the right deallocation routine. */
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enum dl_action_result_errstring_source
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{
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dl_action_result_errstring_constant, /* String literal, no deallocation. */
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dl_action_result_errstring_rtld, /* libc in the primary namespace. */
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dl_action_result_errstring_local, /* libc in the current namespace. */
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};
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struct dl_action_result
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{
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int errcode;
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char errstring_source;
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bool returned;
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const char *objname;
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char *errstring;
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};
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/* Used to free the errstring member of struct dl_action_result in the
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dl_action_result_errstring_rtld case. */
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static inline void
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dl_error_free (void *ptr)
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{
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#ifdef SHARED
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/* In the shared case, ld.so may use a different malloc than this
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namespace. */
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GLRO (dl_error_free (ptr));
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#else
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/* Call the implementation directly. It still has to check for
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pointers which cannot be freed, so do not call free directly
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here. */
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_dl_error_free (ptr);
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#endif
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}
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/* Deallocate RESULT->errstring, leaving *RESULT itself allocated. */
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static inline void
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dl_action_result_errstring_free (struct dl_action_result *result)
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{
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switch (result->errstring_source)
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{
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case dl_action_result_errstring_constant:
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break;
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case dl_action_result_errstring_rtld:
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dl_error_free (result->errstring);
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break;
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case dl_action_result_errstring_local:
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free (result->errstring);
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break;
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}
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}
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/* Stand-in for an error result object whose allocation failed. No
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precise message can be reported for this, but an error must still
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be signaled. */
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static struct dl_action_result *const dl_action_result_malloc_failed
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__attribute__ ((unused)) = (struct dl_action_result *) (intptr_t) -1;
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/* Thread-local variable for storing dlfcn failures for subsequent
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reporting via dlerror. */
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extern __thread struct dl_action_result *__libc_dlerror_result
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attribute_tls_model_ie;
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void __libc_dlerror_result_free (void) attribute_hidden;
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#endif /* _DLERROR_H */
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