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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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11
elf/dl-exception.c
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@ -30,6 +30,17 @@
a pointer comparison. See below and in dlfcn/dlerror.c. */
static const char _dl_out_of_memory[] = "out of memory";
/* Call free in the main libc.so. This allows other namespaces to
free pointers on the main libc heap, via GLRO (dl_error_free). It
also avoids calling free on the special, pre-allocated
out-of-memory error message. */
void
_dl_error_free (void *ptr)
{
if (ptr != _dl_out_of_memory)
free (ptr);
}
/* Dummy allocation object used if allocating the message buffer
fails. */
static void