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/evb64260/zuma_pbb.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'board/evb64260') diff --git a/board/evb64260/zuma_pbb.c b/board/evb64260/zuma_pbb.c index cab4fca..aa15fa0 100644 --- a/board/evb64260/zuma_pbb.c +++ b/board/evb64260/zuma_pbb.c @@ -174,14 +174,14 @@ static int last_cmd = 4; /* write increment */ static int last_size = 64; int -do_zuma_init_pbb (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +do_zuma_init_pbb (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { zuma_init_pbb (); return 0; } int -do_zuma_test_dma (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +do_zuma_test_dma (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { if (argc > 1) { last_cmd = simple_strtoul (argv[1], NULL, 10); @@ -194,7 +194,7 @@ do_zuma_test_dma (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) } int -do_zuma_init_mbox (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +do_zuma_init_mbox (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { zuma_mbox_init (); return 0; -- cgit v1.1