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Make sure that argv[] argument pointers are not modified.

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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 <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
This commit is contained in:
Wolfgang Denk 2010-06-28 22:00:46 +02:00
parent b218ccb543
commit 54841ab50c
295 changed files with 671 additions and 670 deletions
Download patch file Download diff file Expand all files Collapse all files

16
common/cmd_bedbug.c
View file

@ -73,7 +73,7 @@ void bedbug_init (void)
* Entry point from the interpreter to the disassembler. Repeated calls
* will resume from the last disassembled address.
* ====================================================================== */
int do_bedbug_dis (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
int do_bedbug_dis (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
ulong addr; /* Address to start disassembly from */
ulong len; /* # of instructions to disassemble */
@ -115,7 +115,7 @@ U_BOOT_CMD (ds, 3, 1, do_bedbug_dis,
* instructions in consecutive memory locations until a '.' (period) is
* entered on a line by itself.
* ====================================================================== */
int do_bedbug_asm (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
int do_bedbug_asm (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
long mem_addr; /* Address to assemble into */
unsigned long instr; /* Machine code for text */
@ -167,7 +167,7 @@ U_BOOT_CMD (as, 2, 0, do_bedbug_asm,
* CPU-specific break point set routine.
* ====================================================================== */
int do_bedbug_break (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
int do_bedbug_break (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
/* -------------------------------------------------- */
if (bug_ctx.do_break)
@ -263,7 +263,7 @@ void bedbug_main_loop (unsigned long addr, struct pt_regs *regs)
* stopped flag in the context so that the breakpoint routine will
* return.
* ====================================================================== */
int do_bedbug_continue (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
int do_bedbug_continue (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
/* -------------------------------------------------- */
@ -286,7 +286,7 @@ U_BOOT_CMD (continue, 1, 0, do_bedbug_continue,
* the address passes control to the CPU-specific set breakpoint routine
* for the current breakpoint number.
* ====================================================================== */
int do_bedbug_step (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
int do_bedbug_step (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned long addr; /* Address to stop at */
@ -317,7 +317,7 @@ U_BOOT_CMD (step, 1, 1, do_bedbug_step,
* the address passes control to the CPU-specific set breakpoint routine
* for the current breakpoint number.
* ====================================================================== */
int do_bedbug_next (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
int do_bedbug_next (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned long addr; /* Address to stop at */
@ -346,7 +346,7 @@ U_BOOT_CMD (next, 1, 1, do_bedbug_next,
* Interpreter command to print the current stack. This assumes an EABI
* architecture, so it starts with GPR R1 and works back up the stack.
* ====================================================================== */
int do_bedbug_stack (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
int do_bedbug_stack (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned long sp; /* Stack pointer */
unsigned long func; /* LR from stack */
@ -391,7 +391,7 @@ U_BOOT_CMD (where, 1, 1, do_bedbug_stack,
* Interpreter command to dump the registers. Calls the CPU-specific
* show registers routine.
* ====================================================================== */
int do_bedbug_rdump (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
int do_bedbug_rdump (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
/* -------------------------------------------------- */