libio: Disable vtable validation for pre-2.1 interposed handles [BZ #25203]

Commit c402355dfa ("libio: Disable
vtable validation in case of interposition [BZ #23313]") only covered
the interposable glibc 2.1 handles, in libio/stdfiles.c.  The
parallel code in libio/oldstdfiles.c needs similar detection logic.

Fixes (again) commit db3476aff1
("libio: Implement vtable verification [BZ #20191]").

Change-Id: Ief6f9f17e91d1f7263421c56a7dc018f4f595c21
(cherry picked from commit cb61630ed7)
This commit is contained in:
Florian Weimer 2019-11-28 14:44:48 +01:00
parent bc42e3bd44
commit 2dc2d678e9
2 changed files with 6 additions and 0 deletions

1
NEWS
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@ -188,6 +188,7 @@ The following bugs are resolved with this release:
[24027] malloc: Integer overflow in realloc
[24097] Can't use 64-bit register for size_t in assembly codes for x32 (CVE-2019-6488)
[24155] x32 memcmp can treat positive length as 0 (if sign bit in RDX is set) (CVE-2019-7309)
[25203] libio: Disable vtable validation for pre-2.1 interposed handles
[25204] Ignore LD_PREFER_MAP_32BIT_EXEC for SUID programs

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@ -87,6 +87,11 @@ _IO_check_libio (void)
stdout->_vtable_offset = stderr->_vtable_offset =
((int) sizeof (struct _IO_FILE)
- (int) sizeof (struct _IO_FILE_complete));
if (_IO_stdin_.vtable != &_IO_old_file_jumps
|| _IO_stdout_.vtable != &_IO_old_file_jumps
|| _IO_stderr_.vtable != &_IO_old_file_jumps)
IO_set_accept_foreign_vtables (&_IO_vtable_check);
}
}