55a1911ef2
check_deferred_signal() returns twice, since handle_signal() emulates the return from the normal signal handler by sigreturn(2)ing the passed context. Second return is performed on the destroyed stack frame, because __fillcontextx() has already returned. This causes undefined and bad behaviour, usually the victim thread gets SIGSEGV. Avoid nested frame and the need to return from it by doing direct call to getcontext() in the check_deferred_signal() and using a new private libc helper __fillcontextx2() to complement the context with the extended CPU state if the deferred signal is still present. The __fillcontextx() is now unused, but is kept to allow older libthr.so to be used with the new libc. Mark __fillcontextx() as returning twice [1]. Reported by: pgj Pointy hat to: kib Discussed with: dim Tested by: pgj, dim Suggested by: jilles [1] MFC after: 1 week
77 lines
2.0 KiB
C
77 lines
2.0 KiB
C
/*
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* Copyright (c) 2011 Konstantin Belousov <kib@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/ucontext.h>
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#include <errno.h>
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#include <stdlib.h>
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int
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__getcontextx_size(void)
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{
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return (sizeof(ucontext_t));
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}
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int
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__fillcontextx2(char *ctx)
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{
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return (0);
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}
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int
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__fillcontextx(char *ctx)
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{
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ucontext_t *ucp;
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ucp = (ucontext_t *)ctx;
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return (getcontext(ucp));
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}
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__weak_reference(__getcontextx, getcontextx);
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ucontext_t *
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__getcontextx(void)
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{
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char *ctx;
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int error;
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ctx = malloc(__getcontextx_size());
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if (ctx == NULL)
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return (NULL);
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if (__fillcontextx(ctx) == -1) {
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error = errno;
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free(ctx);
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errno = error;
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return (NULL);
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}
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return ((ucontext_t *)ctx);
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}
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