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 --- board/netstar/crcit.c | 2 +- board/netstar/eeprom.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'board/netstar') diff --git a/board/netstar/crcit.c b/board/netstar/crcit.c index 0eef41a11ed..a16264914cb 100644 --- a/board/netstar/crcit.c +++ b/board/netstar/crcit.c @@ -71,7 +71,7 @@ static int do_crc(char *path, unsigned version) return EXIT_SUCCESS; } -int main(int argc, char **argv) +int main(int argc, char * const *argv) { if (argc == 2) { return do_crc(argv[1], 0); diff --git a/board/netstar/eeprom.c b/board/netstar/eeprom.c index aca4458e29b..aa375a4b1a7 100644 --- a/board/netstar/eeprom.c +++ b/board/netstar/eeprom.c @@ -149,7 +149,7 @@ static int parse_element(char *s, unsigned char *buf, int len) return cnt; } -int eeprom(int argc, char *argv[]) +int eeprom(int argc, char * const argv[]) { int i, len, ret; unsigned char buf[58], *p; -- cgit v1.2.3