This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: glibc 2.19 - asyn-signal safe TLS and ASan.
- From: Paul Pluzhnikov <ppluzhnikov at google dot com>
- To: OndÅej BÃlka <neleai at seznam dot cz>
- Cc: Kostya Serebryany <kcc at google dot com>, "Joseph S. Myers" <joseph at codesourcery dot com>, Andrew Hunter <ahh at google dot com>, "Carlos O'Donell" <carlos at redhat dot com>, GNU C Library <libc-alpha at sourceware dot org>, Roland McGrath <roland at hack dot frob dot com>, address-sanitizer at googlegroups dot com
- Date: Fri, 24 Jan 2014 17:12:28 -0800
- Subject: Re: glibc 2.19 - asyn-signal safe TLS and ASan.
- Authentication-results: sourceware.org; auth=none
- References: <52D0BCED dot 3000109 at redhat dot com> <52DDBF0E dot 8010501 at redhat dot com> <CAN=P9piS3Xczq2AKrzh4rsK9JxiHtJXawcQs9_+xsYXxrbLQWQ at mail dot gmail dot com> <CADroS=6vODmWCdBsynOf7oM9uVDymwdxrSDFbmD6kT5P9gbBRw at mail dot gmail dot com> <CAN=P9pgAYNZBUBbg2_SiwCjB5vXJ6ZXTNS=yoZWSvS3JoX1bGQ at mail dot gmail dot com> <52E2A098 dot 7060908 at google dot com> <Pine dot LNX dot 4 dot 64 dot 1401241747120 dot 9799 at digraph dot polyomino dot org dot uk> <CAN=P9pio-MWtJ=F4MmjA5_NJexv1nC12tR=Ue7iD3uq-ootG+w at mail dot gmail dot com> <20140125010534 dot GA14587 at domone dot podge>
On Fri, Jan 24, 2014 at 5:05 PM, OndÅej BÃlka <neleai@seznam.cz> wrote:
> There would be a possible hack to override mmap and look for mmap that
> with dl_addr in backtrace.
That is unlikely to work:
(gdb) disas __signal_safe_memalign
Dump of assembler code for function __signal_safe_memalign:
...
0x00000000000103e2 <+114>: callq 0x18500 <mmap64>
...
That is, the call to mmap64 does not go through PLT, and overriding it is
just as difficult as overriding __signal_safe_memalign :-(
--
Paul Pluzhnikov