libio: Disable vtable validation in case of interposition [BZ #23313]

(cherry picked from commit c402355dfa7807b8e0adb27c009135a7e2b9f1b0)
This commit is contained in:
Florian Weimer 2018-06-26 10:24:52 +02:00
parent 74d16a57a3
commit 2781bd5a86
3 changed files with 22 additions and 0 deletions

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@ -1,3 +1,8 @@
2018-06-26 Florian Weimer <fweimer@redhat.com>
[BZ #23313]
* libio/vtables.c (check_stdfiles_vtables): New ELF constructor.
2017-11-15 Steve Ellcey <sellcey@cavium.com>
[BZ #22442]

1
NEWS
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@ -144,6 +144,7 @@ The following bugs are resolved with this release:
[23171] Fix parameter type in C++ version of iseqsig
[23196] __mempcpy_avx512_no_vzeroupper mishandles large copies
[23236] Harden function pointers in _IO_str_fields
[23313] libio: Disable vtable validation in case of interposition
[23349] Various glibc headers no longer compatible with <linux/time.h>
Version 2.26

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@ -70,3 +70,19 @@ _IO_vtable_check (void)
__libc_fatal ("Fatal error: glibc detected an invalid stdio handle\n");
}
/* Some variants of libstdc++ interpose _IO_2_1_stdin_ etc. and
install their own vtables directly, without calling _IO_init or
other functions. Detect this by looking at the vtables values
during startup, and disable vtable validation in this case. */
#ifdef SHARED
__attribute__ ((constructor))
static void
check_stdfiles_vtables (void)
{
if (_IO_2_1_stdin_.vtable != &_IO_file_jumps
|| _IO_2_1_stdout_.vtable != &_IO_file_jumps
|| _IO_2_1_stderr_.vtable != &_IO_file_jumps)
IO_set_accept_foreign_vtables (&_IO_vtable_check);
}
#endif