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/freescale/common/ngpixis.c | 2 +- board/freescale/common/pixis.c | 6 +++--- board/freescale/common/sys_eeprom.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) (limited to 'board/freescale/common') diff --git a/board/freescale/common/ngpixis.c b/board/freescale/common/ngpixis.c index bb6794e859..a135fbe5ef 100644 --- a/board/freescale/common/ngpixis.c +++ b/board/freescale/common/ngpixis.c @@ -92,7 +92,7 @@ void set_altbank(void) } -int pixis_reset_cmd(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int pixis_reset_cmd(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { unsigned int i; char *p_altbank = NULL; diff --git a/board/freescale/common/pixis.c b/board/freescale/common/pixis.c index 119eaf95af..a35b5cfe3e 100644 --- a/board/freescale/common/pixis.c +++ b/board/freescale/common/pixis.c @@ -284,7 +284,7 @@ static void set_px_go_with_watchdog(void) * */ static int pixis_disable_watchdog_cmd(cmd_tbl_t *cmdtp, int flag, int argc, - char *argv[]) + char * const argv[]) { /* Disable the VELA sequencer and the watchdog */ clrbits_8(pixis_base + PIXIS_VCTL, 9); @@ -302,7 +302,7 @@ U_BOOT_CMD( /* Enable or disable SGMII mode for a TSEC */ -static int pixis_set_sgmii(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int pixis_set_sgmii(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { int which_tsec = -1; unsigned char mask; @@ -430,7 +430,7 @@ static unsigned long strfractoint(char *strptr) return intval + decval; } -static int pixis_reset_cmd(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int pixis_reset_cmd(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { unsigned int i; char *p_cf = NULL; diff --git a/board/freescale/common/sys_eeprom.c b/board/freescale/common/sys_eeprom.c index 661015e000..5a8f4f5810 100644 --- a/board/freescale/common/sys_eeprom.c +++ b/board/freescale/common/sys_eeprom.c @@ -314,7 +314,7 @@ static void set_mac_address(unsigned int index, const char *string) update_crc(); } -int do_mac(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_mac(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char cmd; -- cgit