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https://github.com/smaeul/u-boot.git
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54841ab50c
The hush shell dynamically allocates (and re-allocates) memory for the
argument strings in the "char *argv[]" argument vector passed to
commands. Any code that modifies these pointers will cause serious
corruption of the malloc data structures and crash U-Boot, so make
sure the compiler can check that no such modifications are being done
by changing the code into "char * const argv[]".
This modification is the result of debugging a strange crash caused
after adding a new command, which used the following argument
processing code which has been working perfectly fine in all Unix
systems since version 6 - but not so in U-Boot:
int main (int argc, char **argv)
{
while (--argc > 0 && **++argv == '-') {
/* ====> */ while (*++*argv) {
switch (**argv) {
case 'd':
debug++;
break;
...
default:
usage ();
}
}
}
...
}
The line marked "====>" will corrupt the malloc data structures and
usually cause U-Boot to crash when the next command gets executed by
the shell. With the modification, the compiler will prevent this with
an
error: increment of read-only location '*argv'
N.B.: The code above can be trivially rewritten like this:
while (--argc > 0 && **++argv == '-') {
char *arg = *argv;
while (*++arg) {
switch (*arg) {
...
Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
/*
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* (C) Copyright 2005
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* 2N Telekomunikace, Ladislav Michl <michl@2n.cz>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include "crcek.h"
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extern uint32_t crc32(uint32_t, const unsigned char *, uint);
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static uint32_t data[LOADER_SIZE/4 + 3];
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static int do_crc(char *path, unsigned version)
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{
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uint32_t *p;
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ssize_t size;
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int fd;
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fd = open(path, O_RDONLY);
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if (fd == -1) {
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perror("Error opening file");
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return EXIT_FAILURE;
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}
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p = data + 2;
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size = read(fd, p, LOADER_SIZE + 4);
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if (size == -1) {
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perror("Error reading file");
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return EXIT_FAILURE;
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}
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if (size > LOADER_SIZE) {
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fprintf(stderr, "File too large\n");
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return EXIT_FAILURE;
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}
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size = (size + 3) & ~3; /* round up to 4 bytes */
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size += 4; /* add size of version field */
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data[0] = size;
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data[1] = version;
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data[size/4 + 1] = crc32(0, (unsigned char *)(data + 1), size);
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close(fd);
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if (write(STDOUT_FILENO, data, size + 4 /*size*/ + 4 /*crc*/) == -1) {
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perror("Error writing file");
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return EXIT_FAILURE;
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}
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return EXIT_SUCCESS;
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}
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int main(int argc, char * const *argv)
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{
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if (argc == 2) {
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return do_crc(argv[1], 0);
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} else if ((argc == 4) && (strcmp(argv[1], "-v") == 0)) {
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char *endptr, *nptr = argv[2];
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unsigned ver = strtoul(nptr, &endptr, 0);
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if (*nptr != '\0' && *endptr == '\0')
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return do_crc(argv[3], ver);
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}
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fprintf(stderr, "Usage: crcit [-v version] <image>\n");
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return EXIT_FAILURE;
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}
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