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/digsy_mtc/cmd_mtc.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'board/digsy_mtc') diff --git a/board/digsy_mtc/cmd_mtc.c b/board/digsy_mtc/cmd_mtc.c index ecea5b3c54..621980dfce 100644 --- a/board/digsy_mtc/cmd_mtc.c +++ b/board/digsy_mtc/cmd_mtc.c @@ -68,7 +68,7 @@ static void mtc_calculate_checksum(tx_msp_cmd *packet) packet->cks += buff[i]; } -static int do_mtc_led(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int do_mtc_led(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { tx_msp_cmd pcmd; rx_msp_cmd prx; @@ -120,7 +120,7 @@ static int do_mtc_led(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return err; } -static int do_mtc_key(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int do_mtc_key(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { tx_msp_cmd pcmd; rx_msp_cmd prx; @@ -142,7 +142,7 @@ static int do_mtc_key(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return err; } -static int do_mtc_digout(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int do_mtc_digout(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { tx_msp_cmd pcmd; rx_msp_cmd prx; @@ -171,7 +171,7 @@ static int do_mtc_digout(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return err; } -static int do_mtc_digin(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int do_mtc_digin(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { tx_msp_cmd pcmd; rx_msp_cmd prx; @@ -205,7 +205,7 @@ static int do_mtc_digin(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return err; } -static int do_mtc_appreg(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int do_mtc_appreg(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { tx_msp_cmd pcmd; rx_msp_cmd prx; @@ -232,7 +232,7 @@ static int do_mtc_appreg(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return err; } -static int do_mtc_version(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int do_mtc_version(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { tx_msp_cmd pcmd; rx_msp_cmd prx; @@ -254,7 +254,7 @@ static int do_mtc_version(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return err; } -static int do_mtc_state(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int do_mtc_state(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { tx_msp_cmd pcmd; rx_msp_cmd prx; @@ -281,7 +281,7 @@ static int do_mtc_state(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return err; } -static int do_mtc_help(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]); +static int do_mtc_help(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]); cmd_tbl_t cmd_mtc_sub[] = { U_BOOT_CMD_MKENT(led, 3, 1, do_mtc_led, @@ -308,11 +308,11 @@ cmd_tbl_t cmd_mtc_sub[] = { "[command] - get help for command\n"), }; -static int do_mtc_help(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int do_mtc_help(cmd_tbl_t *cmdtp, int flag, 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[]); #ifdef CONFIG_SYS_LONGHELP puts("mtc "); #endif @@ -320,7 +320,7 @@ static int do_mtc_help(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) ARRAY_SIZE(cmd_mtc_sub), cmdtp, flag, argc, argv); } -int cmd_mtc(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int cmd_mtc(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { cmd_tbl_t *c; int err = 0; -- cgit v1.2.3