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authorWolfgang Denk <wd@denx.de>2010-06-28 22:00:46 +0200
committerWolfgang Denk <wd@denx.de>2010-07-04 23:55:42 +0200
commit54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch)
tree400f22f0a12ff0ae6c472bed6ac648befc1744a2 /common/cmd_net.c
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
downloadu-boot-linaro-natty-54841ab50c20d6fa6c9cc3eb826989da3a22d934.tar.gz
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_net.c')
-rw-r--r--common/cmd_net.c24
1 files changed, 12 insertions, 12 deletions
diff --git a/common/cmd_net.c b/common/cmd_net.c
index b80a7ad8e..3cdb07fdc 100644
--- a/common/cmd_net.c
+++ b/common/cmd_net.c
@@ -28,11 +28,11 @@
#include <command.h>
#include <net.h>
-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);