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/sparc/cpu/leon2/cpu.c | 2 +- arch/sparc/cpu/leon2/interrupts.c | 2 +- arch/sparc/cpu/leon3/cpu.c | 2 +- arch/sparc/cpu/leon3/interrupts.c | 2 +- arch/sparc/include/asm/prom.h | 2 +- arch/sparc/lib/board.c | 2 +- arch/sparc/lib/bootm.c | 2 +- 7 files changed, 7 insertions(+), 7 deletions(-) (limited to 'arch/sparc') diff --git a/arch/sparc/cpu/leon2/cpu.c b/arch/sparc/cpu/leon2/cpu.c index d6e23b1..46512c7 100644 --- a/arch/sparc/cpu/leon2/cpu.c +++ b/arch/sparc/cpu/leon2/cpu.c @@ -49,7 +49,7 @@ void cpu_reset(void) _reset_reloc(); } -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[]) { cpu_reset(); diff --git a/arch/sparc/cpu/leon2/interrupts.c b/arch/sparc/cpu/leon2/interrupts.c index 9b0da96..5149550 100644 --- a/arch/sparc/cpu/leon2/interrupts.c +++ b/arch/sparc/cpu/leon2/interrupts.c @@ -195,7 +195,7 @@ void irq_free_handler(int irq) /****************************************************************************/ #if defined(CONFIG_CMD_IRQ) -void do_irqinfo(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[]) +void do_irqinfo(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[]) { int irq; unsigned int pil = get_pil(); diff --git a/arch/sparc/cpu/leon3/cpu.c b/arch/sparc/cpu/leon3/cpu.c index 976f311..a1646e2 100644 --- a/arch/sparc/cpu/leon3/cpu.c +++ b/arch/sparc/cpu/leon3/cpu.c @@ -52,7 +52,7 @@ void cpu_reset(void) _reset_reloc(); } -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[]) { cpu_reset(); diff --git a/arch/sparc/cpu/leon3/interrupts.c b/arch/sparc/cpu/leon3/interrupts.c index ac6aca5..4138f9b 100644 --- a/arch/sparc/cpu/leon3/interrupts.c +++ b/arch/sparc/cpu/leon3/interrupts.c @@ -197,7 +197,7 @@ void irq_free_handler(int irq) /****************************************************************************/ #if defined(CONFIG_CMD_IRQ) -void do_irqinfo(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[]) +void do_irqinfo(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[]) { int irq; unsigned int pil = get_pil(); diff --git a/arch/sparc/include/asm/prom.h b/arch/sparc/include/asm/prom.h index d55cc86..12901bc 100644 --- a/arch/sparc/include/asm/prom.h +++ b/arch/sparc/include/asm/prom.h @@ -79,7 +79,7 @@ struct linux_mem_v0 { /* Arguments sent to the kernel from the boot prompt. */ struct linux_arguments_v0 { - char *argv[8]; + char * const argv[8]; char args[100]; char boot_dev[2]; int boot_dev_ctrl; diff --git a/arch/sparc/lib/board.c b/arch/sparc/lib/board.c index 11eea60..b776c21 100644 --- a/arch/sparc/lib/board.c +++ b/arch/sparc/lib/board.c @@ -63,7 +63,7 @@ DECLARE_GLOBAL_DATA_PTR; extern void timer_interrupt_init(void); extern void malloc_bin_reloc(void); -extern int do_ambapp_print(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]); +extern int do_ambapp_print(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]); extern int prom_init(void); #if defined(CONFIG__CMD_DOC) diff --git a/arch/sparc/lib/bootm.c b/arch/sparc/lib/bootm.c index c62cf57..4c226a3 100644 --- a/arch/sparc/lib/bootm.c +++ b/arch/sparc/lib/bootm.c @@ -92,7 +92,7 @@ void arch_lmb_reserve(struct lmb *lmb) } /* boot the linux kernel */ -int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t * images) +int do_bootm_linux(int flag, int argc, char * const argv[], bootm_headers_t * images) { char *bootargs; ulong initrd_start, initrd_end; -- cgit v1.1