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 --- arch/powerpc/cpu/mpc86xx/cpu.c | 2 +- arch/powerpc/cpu/mpc86xx/interrupts.c | 2 +- arch/powerpc/cpu/mpc86xx/mp.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/cpu/mpc86xx') diff --git a/arch/powerpc/cpu/mpc86xx/cpu.c b/arch/powerpc/cpu/mpc86xx/cpu.c index 188757587..9064e7803 100644 --- a/arch/powerpc/cpu/mpc86xx/cpu.c +++ b/arch/powerpc/cpu/mpc86xx/cpu.c @@ -124,7 +124,7 @@ checkcpu(void) void -do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { volatile immap_t *immap = (immap_t *)CONFIG_SYS_IMMR; volatile ccsr_gur_t *gur = &immap->im_gur; diff --git a/arch/powerpc/cpu/mpc86xx/interrupts.c b/arch/powerpc/cpu/mpc86xx/interrupts.c index c78fc7225..d8ad6d30d 100644 --- a/arch/powerpc/cpu/mpc86xx/interrupts.c +++ b/arch/powerpc/cpu/mpc86xx/interrupts.c @@ -101,7 +101,7 @@ void irq_free_handler(int vec) /* * irqinfo - print information about PCI devices,not implemented. */ -int do_irqinfo(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_irqinfo(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { return 0; } diff --git a/arch/powerpc/cpu/mpc86xx/mp.c b/arch/powerpc/cpu/mpc86xx/mp.c index b4a0faacd..24eb30aaa 100644 --- a/arch/powerpc/cpu/mpc86xx/mp.c +++ b/arch/powerpc/cpu/mpc86xx/mp.c @@ -66,7 +66,7 @@ int cpu_disable(int nr) return 0; } -int cpu_release(int nr, int argc, char *argv[]) +int cpu_release(int nr, int argc, char * const argv[]) { /* dummy function so common/cmd_mp.c will build * should be implemented in the future */ -- cgit v1.2.3