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[glibc/release/2.24/master] libio: Disable vtable validation in case of interposition [BZ #23313]
- From: Florian Weimer <fw at sourceware dot org>
- To: glibc-cvs at sourceware dot org
- Date: 28 Nov 2019 16:45:26 -0000
- Subject: [glibc/release/2.24/master] libio: Disable vtable validation in case of interposition [BZ #23313]
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=1154cb63e725a579def2d7ba8383fd950931342b
commit 1154cb63e725a579def2d7ba8383fd950931342b
Author: Florian Weimer <fweimer@redhat.com>
Date: Tue Jun 26 10:24:52 2018 +0200
libio: Disable vtable validation in case of interposition [BZ #23313]
(cherry picked from commit c402355dfa7807b8e0adb27c009135a7e2b9f1b0)
Diff:
---
ChangeLog | 5 +++++
libio/vtables.c | 16 ++++++++++++++++
2 files changed, 21 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index 3ca1f72..3eba763 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2018-06-26 Florian Weimer <fweimer@redhat.com>
+
+ [BZ #23313]
+ * libio/vtables.c (check_stdfiles_vtables): New ELF constructor.
+
2019-11-01 Dragan Mladjenovic <dmladjenovic@wavecomp.com>
* sysdeps/unix/sysv/linux/mips/Makefile
diff --git a/libio/vtables.c b/libio/vtables.c
index b361f44..722a090 100644
--- a/libio/vtables.c
+++ b/libio/vtables.c
@@ -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