diff options
| author | Wolfgang Denk | 2010-06-28 22:00:46 +0200 |
|---|---|---|
| committer | Wolfgang Denk | 2010-07-04 23:55:42 +0200 |
| commit | 54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch) | |
| tree | 400f22f0a12ff0ae6c472bed6ac648befc1744a2 /common/cmd_dcr.c | |
| parent | b218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff) | |
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>
Diffstat (limited to 'common/cmd_dcr.c')
| -rw-r--r-- | common/cmd_dcr.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/common/cmd_dcr.c b/common/cmd_dcr.c index 4f23b8d5911..45de8cd65a8 100644 --- a/common/cmd_dcr.c +++ b/common/cmd_dcr.c @@ -36,7 +36,7 @@ unsigned long set_dcr (unsigned short, unsigned long); * Interpreter command to retrieve an AMCC PPC 4xx Device Control Register * ======================================================================= */ -int do_getdcr ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[] ) +int do_getdcr ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[] ) { unsigned short dcrn; /* Device Control Register Num */ unsigned long value; /* DCR's value */ @@ -63,7 +63,7 @@ int do_getdcr ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[] ) * Interpreter command to set an AMCC PPC 4xx Device Control Register * ====================================================================== */ -int do_setdcr (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) +int do_setdcr (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]) { unsigned short dcrn; /* Device Control Register Num */ unsigned long value; @@ -110,7 +110,7 @@ int do_setdcr (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) * Device Control Register inderect addressing. * ======================================================================= */ -int do_getidcr (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_getidcr (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { unsigned short adr_dcrn; /* Device Control Register Num for Address */ unsigned short dat_dcrn; /* Device Control Register Num for Data */ @@ -166,7 +166,7 @@ int do_getidcr (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) * Device Control Register inderect addressing. * ======================================================================= */ -int do_setidcr (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) +int do_setidcr (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]) { unsigned short adr_dcrn; /* Device Control Register Num for Address */ unsigned short dat_dcrn; /* Device Control Register Num for Data */ |