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 --- common/cmd_net.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'common/cmd_net.c') diff --git a/common/cmd_net.c b/common/cmd_net.c index b80a7ad..3cdb07f 100644 --- a/common/cmd_net.c +++ b/common/cmd_net.c @@ -28,11 +28,11 @@ #include #include -extern int do_bootm (cmd_tbl_t *, int, int, char *[]); +extern int do_bootm (cmd_tbl_t *, int, int, char * const []); -static int netboot_common (proto_t, cmd_tbl_t *, int , char *[]); +static int netboot_common (proto_t, cmd_tbl_t *, int , char * const []); -int do_bootp (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_bootp (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { return netboot_common (BOOTP, cmdtp, argc, argv); } @@ -43,7 +43,7 @@ U_BOOT_CMD( "[loadAddress] [[hostIPaddr:]bootfilename]" ); -int do_tftpb (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_tftpb (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { return netboot_common (TFTP, cmdtp, argc, argv); } @@ -54,7 +54,7 @@ U_BOOT_CMD( "[loadAddress] [[hostIPaddr:]bootfilename]" ); -int do_rarpb (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_rarpb (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { return netboot_common (RARP, cmdtp, argc, argv); } @@ -66,7 +66,7 @@ U_BOOT_CMD( ); #if defined(CONFIG_CMD_DHCP) -int do_dhcp (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_dhcp (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { return netboot_common(DHCP, cmdtp, argc, argv); } @@ -79,7 +79,7 @@ U_BOOT_CMD( #endif #if defined(CONFIG_CMD_NFS) -int do_nfs (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_nfs (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { return netboot_common(NFS, cmdtp, argc, argv); } @@ -151,7 +151,7 @@ static void netboot_update_env (void) } static int -netboot_common (proto_t proto, cmd_tbl_t *cmdtp, int argc, char *argv[]) +netboot_common (proto_t proto, cmd_tbl_t *cmdtp, int argc, char * const argv[]) { char *s; char *end; @@ -230,7 +230,7 @@ netboot_common (proto_t proto, cmd_tbl_t *cmdtp, int argc, char *argv[]) } #if defined(CONFIG_CMD_PING) -int do_ping (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_ping (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { if (argc < 2) return -1; @@ -280,7 +280,7 @@ static void cdp_update_env(void) } -int do_cdp (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_cdp (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { int r; @@ -302,7 +302,7 @@ U_BOOT_CMD( #endif #if defined(CONFIG_CMD_SNTP) -int do_sntp (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_sntp (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *toff; @@ -340,7 +340,7 @@ U_BOOT_CMD( #endif #if defined(CONFIG_CMD_DNS) -int do_dns(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_dns(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { if (argc == 1) { cmd_usage(cmdtp); -- cgit v1.1