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f83bb9b8e9
GLIBC execl{e,p} implementation might use malloc if the total number of
arguments exceed initial assumption size (1024). This might lead to
issues in two situations:
1. execl/execle is stated to be async-signal-safe by POSIX [1]. However
if execl is used in a signal handler with a large argument set (that
may call malloc internally) and if the resulting call fails it might
lead malloc in the program in a bad state.
2. If the functions are used in a vfork/clone(VFORK) situation it also
might issue malloc internal bad state.
This patch fixes it by using stack allocation instead. It also fixes
BZ#19534.
Tested on x86_64.
[1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html
[BZ #19534]
* posix/execl.c (execl): Remove dynamic memory allocation.
* posix/execle.c (execle): Likewise.
* posix/execlp.c (execlp): Likewise.
58 lines
1.8 KiB
C
58 lines
1.8 KiB
C
/* Copyright (C) 1991-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <unistd.h>
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#include <errno.h>
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#include <stdarg.h>
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#include <sys/param.h>
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/* Execute PATH with all arguments after PATH until
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a NULL pointer and environment from `environ'. */
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int
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execl (const char *path, const char *arg, ...)
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{
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ptrdiff_t argc;
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va_list ap;
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va_start (ap, arg);
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for (argc = 1; va_arg (ap, const char *); argc++)
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{
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if (argc == INT_MAX)
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{
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va_end (ap);
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errno = E2BIG;
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return -1;
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}
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}
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va_end (ap);
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/* Avoid dynamic memory allocation due two main issues:
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1. The function should be async-signal-safe and a running on a signal
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handler with a fail outcome might lead to malloc bad state.
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2. It might be used in a vfork/clone(VFORK) scenario where using
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malloc also might lead to internal bad state. */
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ptrdiff_t i;
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char *argv[argc + 1];
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va_start (ap, arg);
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argv[0] = (char *) arg;
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for (i = 1; i <= argc; i++)
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argv[i] = va_arg (ap, char *);
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va_end (ap);
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return __execve (path, argv, __environ);
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}
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libc_hidden_def (execl)
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