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/cm5200/fwupdate.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'board/cm5200/fwupdate.c') diff --git a/board/cm5200/fwupdate.c b/board/cm5200/fwupdate.c index 5a27191352..c1a4a19cc0 100644 --- a/board/cm5200/fwupdate.c +++ b/board/cm5200/fwupdate.c @@ -35,9 +35,9 @@ #include "fwupdate.h" -extern int do_bootm(cmd_tbl_t *, int, int, char *[]); +extern int do_bootm(cmd_tbl_t *, int, int, char * const []); extern long do_fat_read(const char *, void *, unsigned long, int); -extern int do_fat_fsload(cmd_tbl_t *, int, int, char *[]); +extern int do_fat_fsload(cmd_tbl_t *, int, int, char * const []); static int load_rescue_image(ulong); @@ -47,7 +47,7 @@ void cm5200_fwupdate(void) char *rsargs; char *tmp = NULL; char ka[16]; - char *argv[3] = { "bootm", ka, NULL }; + char * const argv[3] = { "bootm", ka, NULL }; /* Check if rescue system is disabled... */ if (getenv("norescue")) { @@ -99,7 +99,7 @@ static int load_rescue_image(ulong addr) char *tmp; char dev[7]; char addr_str[16]; - char *argv[6] = { "fatload", "usb", dev, addr_str, nxri, NULL }; + char * const argv[6] = { "fatload", "usb", dev, addr_str, nxri, NULL }; block_dev_desc_t *stor_dev = NULL; cmd_tbl_t *bcmd; -- cgit v1.2.1