cciss: prevent write to cmd[-1] (on stack);

Signed-off-by: Randy Dunlap <rddunlap@osdl.org>

diffstat:=
 drivers/block/cciss.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff -Naurp ./drivers/block/cciss.c~cciss_strlen ./drivers/block/cciss.c
--- ./drivers/block/cciss.c~cciss_strlen	2005-03-14 15:28:18.000000000 -0800
+++ ./drivers/block/cciss.c	2005-03-15 14:53:52.000000000 -0800
@@ -304,7 +304,7 @@ cciss_proc_write(struct file *file, cons
 	if (copy_from_user(cmd, buffer, count)) return -EFAULT;
 	cmd[count] = '\0';
 	len = strlen(cmd);	// above 3 lines ensure safety
-	if (cmd[len-1] == '\n') 
+	if (len && cmd[len-1] == '\n') 
 		cmd[--len] = '\0';
 #	ifdef CONFIG_CISS_SCSI_TAPE
 		if (strcmp("engage scsi", cmd)==0) {