copies arguments into the kernel space and one that operates completely in the kernel space; o use kernel-only version of execve(2) to kill another stackgap in linuxlator/i386. Obtained from: DragonFlyBSD (partially) MFC after: 2 weeks
180 lines
5.1 KiB
C
180 lines
5.1 KiB
C
/*-
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* Copyright (c) 1993, David Greenman
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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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* 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 AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* 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/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/exec.h>
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#include <sys/imgact.h>
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#include <sys/kernel.h>
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#if BYTE_ORDER == LITTLE_ENDIAN
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#define SHELLMAGIC 0x2123 /* #! */
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#else
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#define SHELLMAGIC 0x2321
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#endif
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/*
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* Shell interpreter image activator. An interpreter name beginning
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* at imgp->args->begin_argv is the minimal successful exit requirement.
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*/
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int
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exec_shell_imgact(imgp)
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struct image_params *imgp;
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{
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const char *image_header = imgp->image_header;
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const char *ihp;
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int error, length, offset;
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/* a shell script? */
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if (((const short *) image_header)[0] != SHELLMAGIC)
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return(-1);
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/*
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* Don't allow a shell script to be the shell for a shell
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* script. :-)
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*/
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if (imgp->interpreted)
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return(ENOEXEC);
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imgp->interpreted = 1;
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/*
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* Figure out the number of bytes that need to be reserved in the
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* argument string to copy the contents of the interpreter's command
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* line into the argument string.
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*/
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ihp = &image_header[2];
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offset = 0;
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while (ihp < &image_header[MAXSHELLCMDLEN]) {
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/* Skip any whitespace */
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while ((*ihp == ' ') || (*ihp == '\t')) {
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ihp++;
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continue;
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}
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/* End of line? */
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if ((*ihp == '\n') || (*ihp == '#'))
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break;
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/* Found a token */
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while ((*ihp != ' ') && (*ihp != '\t') && (*ihp != '\n') &&
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(*ihp != '#')) {
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offset++;
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ihp++;
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}
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/* Include terminating nulls in the offset */
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offset++;
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}
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/* If the script gives a null line as the interpreter, we bail */
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if (offset == 0)
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return (ENOEXEC);
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/* Check that we aren't too big */
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if (offset > MAXSHELLCMDLEN)
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return (ENAMETOOLONG);
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/*
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* The full path name of the original script file must be tagged
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* onto the end, adjust the offset to deal with it.
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*
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* The original argv[0] is being replaced, set 'length' to the number
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* of bytes being removed. So 'offset' is the number of bytes being
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* added and 'length' is the number of bytes being removed.
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*/
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offset += strlen(imgp->args->fname) + 1; /* add fname */
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length = (imgp->args->argc == 0) ? 0 :
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strlen(imgp->args->begin_argv) + 1; /* bytes to delete */
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if (offset - length > imgp->args->stringspace)
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return (E2BIG);
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bcopy(imgp->args->begin_argv + length, imgp->args->begin_argv + offset,
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imgp->args->endp - (imgp->args->begin_argv + length));
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offset -= length; /* calculate actual adjustment */
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imgp->args->begin_envv += offset;
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imgp->args->endp += offset;
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imgp->args->stringspace -= offset;
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/*
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* If there were no arguments then we've added one, otherwise
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* decr argc remove old argv[0], incr argc for fname add, net 0
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*/
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if (imgp->args->argc == 0)
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imgp->args->argc = 1;
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/*
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* Loop through the interpreter name yet again, copying as
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* we go.
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*/
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ihp = &image_header[2];
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offset = 0;
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while (ihp < &image_header[MAXSHELLCMDLEN]) {
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/* Skip whitespace */
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while ((*ihp == ' ' || *ihp == '\t')) {
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ihp++;
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continue;
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}
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/* End of line? */
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if ((*ihp == '\n') || (*ihp == '#'))
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break;
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/* Found a token, copy it */
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while ((*ihp != ' ') && (*ihp != '\t') &&
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(*ihp != '\n') && (*ihp != '#')) {
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imgp->args->begin_argv[offset++] = *ihp++;
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}
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imgp->args->begin_argv[offset++] = '\0';
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imgp->args->argc++;
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}
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/*
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* Finally, add the filename onto the end for the interpreter to
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* use and copy the interpreter's name to imgp->interpreter_name
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* for exec to use.
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*/
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error = copystr(imgp->args->fname, imgp->args->buf + offset,
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imgp->args->stringspace, &length);
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if (error == 0)
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error = copystr(imgp->args->begin_argv, imgp->interpreter_name,
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MAXSHELLCMDLEN, &length);
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return (error);
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}
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/*
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* Tell kern_execve.c about it, with a little help from the linker.
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*/
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static struct execsw shell_execsw = { exec_shell_imgact, "#!" };
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EXEC_SET(shell, shell_execsw);
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