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libc dlfcn.c: make dl_iterate_phdr() from libc more useful

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Apparently there are applications that resolve dl_iterate_phdr from libc
and try to call the symbol. Our libc only provides stubs for dl* to
satisfy static linker or statically linked binaries, and is not prepared
to this situation.

Add a code to dso libc to find real dl_iterate_phdr and redirect the
call to it.

Reported by:	yuri
PR:	272992
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2023-08-09 08:07:05 +03:00
parent 0f613ab85e
commit 21a52f9944
1 changed files with 12 additions and 3 deletions
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15
lib/libc/gen/dlfcn.c
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@ -169,7 +169,9 @@ _rtld_thread_init(void *li __unused)
#ifndef IN_LIBDL
static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT;
static struct dl_phdr_info phdr_info;
#ifndef PIC
static mutex_t dl_phdr_info_lock = MUTEX_INITIALIZER;
#endif
static void
dl_init_phdr_info(void)
@ -208,7 +210,16 @@ int
dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused,
void *data __unused)
{
#ifndef IN_LIBDL
#if defined IN_LIBDL
return (0);
#elif defined PIC
int (*r)(int (*)(struct dl_phdr_info *, size_t, void *), void *);
r = dlsym(RTLD_DEFAULT, "dl_iterate_phdr");
if (r == NULL)
return (0);
return (r(callback, data));
#else
tls_index ti;
int ret;
@ -223,8 +234,6 @@ dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused,
ret = callback(&phdr_info, sizeof(phdr_info), data);
mutex_unlock(&dl_phdr_info_lock);
return (ret);
#else
return (0);
#endif
}