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/mpc83xx/cpu.c | 2 +- arch/powerpc/cpu/mpc83xx/ecc.c | 2 +- arch/powerpc/cpu/mpc83xx/interrupts.c | 2 +- arch/powerpc/cpu/mpc83xx/speed.c | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/powerpc/cpu/mpc83xx') diff --git a/arch/powerpc/cpu/mpc83xx/cpu.c b/arch/powerpc/cpu/mpc83xx/cpu.c index d3be90976..b664c641a 100644 --- a/arch/powerpc/cpu/mpc83xx/cpu.c +++ b/arch/powerpc/cpu/mpc83xx/cpu.c @@ -192,7 +192,7 @@ void upmconfig (uint upm, uint *table, uint size) int -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[]) { ulong msr; #ifndef MPC83xx_RESET diff --git a/arch/powerpc/cpu/mpc83xx/ecc.c b/arch/powerpc/cpu/mpc83xx/ecc.c index f3942b411..8dadd64b4 100644 --- a/arch/powerpc/cpu/mpc83xx/ecc.c +++ b/arch/powerpc/cpu/mpc83xx/ecc.c @@ -98,7 +98,7 @@ void ecc_print_status(void) ddr->capture_attributes & ECC_CAPT_ATTR_VLD); } -int do_ecc(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) +int do_ecc(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]) { volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR; volatile ddr83xx_t *ddr = &immap->ddr; diff --git a/arch/powerpc/cpu/mpc83xx/interrupts.c b/arch/powerpc/cpu/mpc83xx/interrupts.c index faffbaf83..446af27c6 100644 --- a/arch/powerpc/cpu/mpc83xx/interrupts.c +++ b/arch/powerpc/cpu/mpc83xx/interrupts.c @@ -90,7 +90,7 @@ void timer_interrupt_cpu (struct pt_regs *regs) */ void -do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[]) +do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char * const argv[]) { } diff --git a/arch/powerpc/cpu/mpc83xx/speed.c b/arch/powerpc/cpu/mpc83xx/speed.c index 500eef1e9..b5076a9af 100644 --- a/arch/powerpc/cpu/mpc83xx/speed.c +++ b/arch/powerpc/cpu/mpc83xx/speed.c @@ -497,7 +497,7 @@ ulong get_bus_freq(ulong dummy) return gd->csb_clk; } -int do_clocks (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) +int do_clocks (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]) { char buf[32]; -- cgit v1.2.3