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[glibc/release/2.28/master] libio: Disable vtable validation for pre-2.1 interposed handles [BZ #25203]
- From: Florian Weimer <fw at sourceware dot org>
- To: glibc-cvs at sourceware dot org
- Date: 28 Nov 2019 14:13:37 -0000
- Subject: [glibc/release/2.28/master] libio: Disable vtable validation for pre-2.1 interposed handles [BZ #25203]
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f55e312bcd6582b5ff68fdcc1781c7017796dc91
commit f55e312bcd6582b5ff68fdcc1781c7017796dc91
Author: Florian Weimer <fweimer@redhat.com>
Date: Thu Nov 28 14:42:11 2019 +0100
libio: Disable vtable validation for pre-2.1 interposed handles [BZ #25203]
Commit c402355dfa7807b8e0adb27c009135a7e2b9f1b0 ("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 db3476aff19b75c4fdefbe65fcd5f0a90588ba51
("libio: Implement vtable verification [BZ #20191]").
Change-Id: Ief6f9f17e91d1f7263421c56a7dc018f4f595c21
(cherry picked from commit cb61630ed712d033f54295f776967532d3f4b46a)
Diff:
---
NEWS | 1 +
libio/oldstdfiles.c | 5 +++++
2 files changed, 6 insertions(+)
diff --git a/NEWS b/NEWS
index 2a97ce5..74efb0e 100644
--- a/NEWS
+++ b/NEWS
@@ -69,6 +69,7 @@ The following bugs are resolved with this release:
[24228] old x86 applications that use legacy libio crash on exit
[24476] dlfcn: Guard __dlerror_main_freeres with __libc_once_get (once)
[24744] io: Remove the copy_file_range emulation.
+ [25203] libio: Disable vtable validation for pre-2.1 interposed handles
[25204] Ignore LD_PREFER_MAP_32BIT_EXEC for SUID programs
Security related changes:
diff --git a/libio/oldstdfiles.c b/libio/oldstdfiles.c
index f3dda89..9fe809b 100644
--- a/libio/oldstdfiles.c
+++ b/libio/oldstdfiles.c
@@ -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);
}
}