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 <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/common/cmd_mem.c b/common/cmd_mem.c
index 1839330..bcea399 100644
--- a/common/cmd_mem.c
+++ b/common/cmd_mem.c
@@ -43,7 +43,7 @@
#define PRINTF(fmt,args...)
#endif
-static int mod_mem(cmd_tbl_t *, int, int, int, char *[]);
+static int mod_mem(cmd_tbl_t *, int, int, int, char * const []);
/* Display values from last command.
* Memory modify remembered values are different from display memory.
@@ -60,7 +60,7 @@
* md{.b, .w, .l} {addr} {len}
*/
#define DISP_LINE_LEN 16
-int do_mem_md ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_md ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong addr, length;
#if defined(CONFIG_HAS_DATAFLASH)
@@ -158,16 +158,16 @@
return (rc);
}
-int do_mem_mm ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_mm ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
return mod_mem (cmdtp, 1, flag, argc, argv);
}
-int do_mem_nm ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_nm ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
return mod_mem (cmdtp, 0, flag, argc, argv);
}
-int do_mem_mw ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_mw ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong addr, writeval, count;
int size;
@@ -211,7 +211,7 @@
}
#ifdef CONFIG_MX_CYCLIC
-int do_mem_mdc ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_mdc ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int i;
ulong count;
@@ -240,7 +240,7 @@
return 0;
}
-int do_mem_mwc ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_mwc ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int i;
ulong count;
@@ -270,7 +270,7 @@
}
#endif /* CONFIG_MX_CYCLIC */
-int do_mem_cmp (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_cmp (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong addr1, addr2, count, ngood;
int size;
@@ -355,7 +355,7 @@
return rcode;
}
-int do_mem_cp ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_cp ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong addr, dest, count;
int size;
@@ -463,7 +463,7 @@
return 0;
}
-int do_mem_base (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_base (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
if (argc > 1) {
/* Set new base address.
@@ -476,7 +476,7 @@
return 0;
}
-int do_mem_loop (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_loop (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong addr, length, i, junk;
int size;
@@ -547,7 +547,7 @@
}
#ifdef CONFIG_LOOPW
-int do_mem_loopw (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_loopw (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong addr, length, i, data;
int size;
@@ -626,7 +626,7 @@
* configured using CONFIG_SYS_ALT_MEMTEST. The complete test loops until
* interrupted by ctrl-c or by a failure of one of the sub-tests.
*/
-int do_mem_mtest (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_mtest (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
vu_long *addr, *start, *end;
ulong val;
@@ -984,7 +984,7 @@
* nm{.b, .w, .l} {addr}
*/
static int
-mod_mem(cmd_tbl_t *cmdtp, int incrflag, int flag, int argc, char *argv[])
+mod_mem(cmd_tbl_t *cmdtp, int incrflag, int flag, int argc, char * const argv[])
{
ulong addr, i;
int nbytes, size;
@@ -1089,7 +1089,7 @@
#ifndef CONFIG_CRC32_VERIFY
-int do_mem_crc (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_crc (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong addr, length;
ulong crc;
@@ -1120,7 +1120,7 @@
#else /* CONFIG_CRC32_VERIFY */
-int do_mem_crc (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mem_crc (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong addr, length;
ulong crc;
@@ -1128,7 +1128,7 @@
ulong vcrc;
int verify;
int ac;
- char **av;
+ char * const *av;
if (argc < 3) {
usage:
@@ -1175,7 +1175,7 @@
#endif /* CONFIG_CRC32_VERIFY */
#ifdef CONFIG_CMD_MD5SUM
-int do_md5sum(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_md5sum(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
unsigned long addr, len;
unsigned int i;
@@ -1200,7 +1200,7 @@
#endif
#ifdef CONFIG_CMD_SHA1
-int do_sha1sum(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_sha1sum(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
unsigned long addr, len;
unsigned int i;
@@ -1225,7 +1225,7 @@
#endif
#ifdef CONFIG_CMD_UNZIP
-int do_unzip ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_unzip ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
unsigned long src, dst;
unsigned long src_len = ~0UL, dst_len = ~0UL;