From 54841ab50c20d6fa6c9cc3eb826989da3a22d934 Mon Sep 17 00:00:00 2001 From: Wolfgang Denk Date: Mon, 28 Jun 2010 22:00:46 +0200 Subject: Make sure that argv[] argument pointers are not modified. 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 Acked-by: Mike Frysinger --- board/inka4x0/inkadiag.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'board/inka4x0/inkadiag.c') diff --git a/board/inka4x0/inkadiag.c b/board/inka4x0/inkadiag.c index 0a75abd..637bb5a 100644 --- a/board/inka4x0/inkadiag.c +++ b/board/inka4x0/inkadiag.c @@ -131,7 +131,7 @@ static void inka_digio_set_output(unsigned int state, int which) } static int do_inkadiag_io(cmd_tbl_t *cmdtp, int flag, int argc, - char *argv[]) { + char * const argv[]) { unsigned int state, val; switch (argc) { @@ -237,7 +237,7 @@ static int ser_getc(volatile struct mpc5xxx_psc *psc) } static int do_inkadiag_serial(cmd_tbl_t *cmdtp, int flag, int argc, - char *argv[]) { + char * const argv[]) { volatile struct NS16550 *uart; volatile struct mpc5xxx_psc *psc; unsigned int num, mode; @@ -389,7 +389,7 @@ static void buzzer_turn_off(void) } static int do_inkadiag_buzzer(cmd_tbl_t *cmdtp, int flag, int argc, - char *argv[]) { + char * const argv[]) { unsigned int period, freq; int prev, i; @@ -435,7 +435,7 @@ static int do_inkadiag_buzzer(cmd_tbl_t *cmdtp, int flag, int argc, return 0; } -static int do_inkadiag_help(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]); +static int do_inkadiag_help(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]); cmd_tbl_t cmd_inkadiag_sub[] = { U_BOOT_CMD_MKENT(io, 1, 1, do_inkadiag_io, "read digital input", @@ -450,10 +450,10 @@ cmd_tbl_t cmd_inkadiag_sub[] = { }; static int do_inkadiag_help(cmd_tbl_t *cmdtp, int flag, - int argc, char *argv[]) { + int argc, char * const argv[]) { extern int _do_help (cmd_tbl_t *cmd_start, int cmd_items, cmd_tbl_t *cmdtp, int flag, - int argc, char *argv[]); + int argc, char * const argv[]); /* do_help prints command name - we prepend inkadiag to our subcommands! */ #ifdef CONFIG_SYS_LONGHELP puts ("inkadiag "); @@ -463,7 +463,7 @@ static int do_inkadiag_help(cmd_tbl_t *cmdtp, int flag, } static int do_inkadiag(cmd_tbl_t *cmdtp, int flag, int argc, - char *argv[]) { + char * const argv[]) { cmd_tbl_t *c; c = find_cmd_tbl(argv[1], &cmd_inkadiag_sub[0], ARRAY_SIZE(cmd_inkadiag_sub)); -- cgit v1.1