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/eltec/bab7xx/bab7xx.c | 2 +- board/eltec/elppc/elppc.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'board/eltec') diff --git a/board/eltec/bab7xx/bab7xx.c b/board/eltec/bab7xx/bab7xx.c index 1f78f8d16e..f5c9777ee1 100644 --- a/board/eltec/bab7xx/bab7xx.c +++ b/board/eltec/bab7xx/bab7xx.c @@ -184,7 +184,7 @@ void after_reloc (ulong dest_addr) * do_reset is done here because in this case it is board specific, since the * 7xx CPUs can only be reset by external HW (the RTC in this case). */ -void do_reset (cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[]) +void do_reset (cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[]) { #if defined(CONFIG_RTC_MK48T59) /* trigger watchdog immediately */ diff --git a/board/eltec/elppc/elppc.c b/board/eltec/elppc/elppc.c index e73c712cbb..cb9ab86cb0 100644 --- a/board/eltec/elppc/elppc.c +++ b/board/eltec/elppc/elppc.c @@ -117,7 +117,7 @@ phys_size_t initdram (int board_type) * Register PI in the MPC 107 (at offset 0x41090 of the Embedded Utilities * Memory Block). */ -int do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) +int do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]) { out8 (MPC107_EUMB_PI, 1); return (0); -- cgit v1.2.3