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/mpc85xx/cpu.c | 2 +- arch/powerpc/cpu/mpc85xx/interrupts.c | 2 +- arch/powerpc/cpu/mpc85xx/mp.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/cpu/mpc85xx') diff --git a/arch/powerpc/cpu/mpc85xx/cpu.c b/arch/powerpc/cpu/mpc85xx/cpu.c index fddeb2f..6f81fdf 100644 --- a/arch/powerpc/cpu/mpc85xx/cpu.c +++ b/arch/powerpc/cpu/mpc85xx/cpu.c @@ -186,7 +186,7 @@ int checkcpu (void) /* ------------------------------------------------------------------------- */ -int do_reset (cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[]) +int do_reset (cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char * const argv[]) { /* Everything after the first generation of PQ3 parts has RSTCR */ #if defined(CONFIG_MPC8540) || defined(CONFIG_MPC8541) || \ diff --git a/arch/powerpc/cpu/mpc85xx/interrupts.c b/arch/powerpc/cpu/mpc85xx/interrupts.c index 409367d..ac8c01a 100644 --- a/arch/powerpc/cpu/mpc85xx/interrupts.c +++ b/arch/powerpc/cpu/mpc85xx/interrupts.c @@ -103,7 +103,7 @@ void timer_interrupt_cpu(struct pt_regs *regs) #if defined(CONFIG_CMD_IRQ) /* 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/mpc85xx/mp.c b/arch/powerpc/cpu/mpc85xx/mp.c index 826bf32..ddbc221 100644 --- a/arch/powerpc/cpu/mpc85xx/mp.c +++ b/arch/powerpc/cpu/mpc85xx/mp.c @@ -105,7 +105,7 @@ static u8 boot_entry_map[4] = { BOOT_ENTRY_R6_LOWER, }; -int cpu_release(int nr, int argc, char *argv[]) +int cpu_release(int nr, int argc, char * const argv[]) { u32 i, val, *table = (u32 *)get_spin_virt_addr() + nr * NUM_BOOT_ENTRY; u64 boot_addr; -- cgit v1.1