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--- linux/drivers/char/tty_io.c Mon Dec 11 01:49:42 2000
+++ linux-2.2.16/drivers/char/tty_io.c Tue Jan 30 17:49:00 2001
@@ -145,6 +145,168 @@
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
+#ifdef CONFIG_TTYTAP
+
+#include <linux/skbuff.h>
+#include <linux/ttytap.h>
+
+static int tap_major = 0;
+static int tap_minor = 0;
+static int tap_overrun = 0;
+static int tap_qmax = 1024;
+static int tap_used = 0;
+
+typedef struct {
+ struct sk_buff *skb;
+} tap_info;
+
+static struct sk_buff_head tap_queue;
+static struct wait_queue *tap_waitq;
+
+static void record_tap(int io, const char *buf, int len) {
+ struct sk_buff *skb = (struct sk_buff *)dev_alloc_skb(len + sizeof(tapheader));
+ tapheader th;
+
+ if (!skb) {
+ printk(KERN_WARNING "Out of memory in serial record_tap\n");
+ return;
+ }
+ if (skb_queue_len(&tap_queue) > tap_qmax) {
+ tap_overrun = TTYTAP_OVERRUN;
+ dev_kfree_skb(skb);
+ return;
+ }
+ th.io = io | tap_overrun;
+ tap_overrun = 0;
+ th.len = len;
+ th.stamp = xtime;
+ memcpy(skb_put(skb, sizeof(tapheader)), &th, sizeof(tapheader));
+ copy_from_user(skb_put(skb, len), buf, len);
+ skb_queue_tail(&tap_queue, skb);
+ wake_up_interruptible(&tap_waitq);
+}
+
+static ssize_t tap_read(struct file *file, char *buf, size_t count, loff_t *off)
+{
+ tap_info *info = (tap_info *) file->private_data;
+ int rcount = 0;
+
+ if (off != &file->f_pos)
+ return -ESPIPE;
+
+ while (!(info->skb || (info->skb = skb_dequeue(&tap_queue)))) {
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+ interruptible_sleep_on(&tap_waitq);
+ if (signal_pending(current))
+ return -ERESTARTSYS;
+ }
+ while (count > 0) {
+ int len;
+
+ if (!info->skb)
+ info->skb = skb_dequeue(&tap_queue);
+ if (!info->skb)
+ break;
+ len = (info->skb->len > count) ? count : info->skb->len;
+ if (len > 0) {
+ if (copy_to_user(buf, info->skb->data, len))
+ return -EFAULT;
+ skb_pull(info->skb, len);
+ buf += len;
+ rcount += len;
+ count -= len;
+ if (info->skb->len == 0) {
+ kfree_skb(info->skb);
+ info->skb = NULL;
+ }
+ } else
+ break;
+ }
+ return rcount;
+}
+
+static int tap_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
+{
+ int v;
+
+ switch (cmd) {
+ case TTYTAP_SETDEV:
+ tap_major = (arg >> 8) & 255;
+ tap_minor = arg & 255;
+ if ((tap_major == 0) && (tap_minor == 0)) {
+ skb_queue_purge(&tap_queue);
+ tap_overrun = 0;
+ }
+ return 0;
+ case TTYTAP_GETDEV:
+ v = (tap_major << 8) | tap_minor;
+ if (copy_to_user((char *)arg, &v, sizeof(v)))
+ return -EFAULT;
+ return 0;
+ case TTYTAP_SETQLEN:
+ tap_qmax = arg;
+ return 0;
+ case TTYTAP_GETQLEN:
+ if (copy_to_user((char *)arg, &tap_qmax, sizeof(tap_qmax)))
+ return -EFAULT;
+ return 0;
+ }
+ return -EINVAL;
+}
+
+static int tap_open(struct inode *inode, struct file *file)
+{
+ tap_info *info;
+
+ if (test_and_set_bit(0, &tap_used))
+ return -EBUSY;
+ info = kmalloc(sizeof(tap_info), GFP_KERNEL);
+ if (!info) {
+ clear_bit(0, &tap_used);
+ return -ENOMEM;
+ }
+ memset(info, 0, sizeof(tap_info));
+ file->private_data = (void *)info;
+ return 0;
+}
+
+static int tap_close(struct inode *inode, struct file *file)
+{
+ tap_info *info = (tap_info *)file->private_data;
+ if (info->skb)
+ kfree_skb(info->skb);
+ kfree(info);
+ clear_bit(0, &tap_used);
+ return 0;
+}
+
+static struct file_operations tap_fops = {
+ NULL, /* lseek */
+ tap_read, /* read */
+ NULL, /* write */
+ NULL, /* readdir */
+ NULL, /* poll */
+ tap_ioctl, /* ioctl */
+ NULL, /* mmap */
+ tap_open, /* open */
+ NULL, /* flush */
+ tap_close, /* close */
+ NULL, /* fsync */
+};
+
+static struct inode_operations tap_iops = {
+ &tap_fops,
+};
+
+static struct proc_dir_entry tap_entry = {
+ 0, 6, "ttytap",
+ S_IFREG | S_IRUSR | S_IWUSR, 1, 0, 0,
+ 0, &tap_iops,
+};
+
+#endif
+
/*
* This routine returns the name of tty.
*/
@@ -649,6 +811,11 @@
i = -EIO;
if (i > 0)
inode->i_atime = CURRENT_TIME;
+#ifdef CONFIG_TTYTAP
+ if ((MAJOR(inode->i_rdev) == tap_major) &&
+ (MINOR(inode->i_rdev) == tap_minor) && (i > 0))
+ record_tap(TTYTAP_IN, buf, i);
+#endif
return i;
}
@@ -709,6 +876,9 @@
int is_console;
struct tty_struct * tty;
struct inode *inode;
+#ifdef CONFIG_TTYTAP
+ ssize_t ret;
+#endif
/* Can't seek (pwrite) on ttys. */
if (ppos != &file->f_pos)
@@ -743,8 +913,19 @@
#endif
if (!tty->ldisc.write)
return -EIO;
+#ifdef CONFIG_TTYTAP
+ ret = do_tty_write(tty->ldisc.write, tty, file,
+ (const unsigned char *)buf, count);
+#else
return do_tty_write(tty->ldisc.write, tty, file,
(const unsigned char *)buf, count);
+#endif
+#ifdef CONFIG_TTYTAP
+ if ((MAJOR(inode->i_rdev) == tap_major) &&
+ (MINOR(inode->i_rdev) == tap_minor) && (ret > 0))
+ record_tap(TTYTAP_OUT, buf, ret);
+ return ret;
+#endif
}
/* Semaphore to protect creating and releasing a tty */
@@ -2243,6 +2424,11 @@
#endif
#ifdef CONFIG_VT
vcs_init();
+#endif
+#ifdef CONFIG_TTYTAP
+ skb_queue_head_init(&tap_queue);
+ clear_bit(0, &tap_used);
+ proc_register(&proc_root, &tap_entry);
#endif
return 0;
}
--- linux/include/linux/ttytap.h Thu Jan 1 01:00:00 1970
+++ linux-2.2.16/include/linux/ttytap.h Mon Sep 11 08:47:09 2000
@@ -0,0 +1,19 @@
+#ifndef _TTYTAP_H_
+#define _TTYTAP_H_
+
+#define TTYTAP_IN 0
+#define TTYTAP_OUT 1
+#define TTYTAP_OVERRUN 2
+
+#define TTYTAP_SETDEV _IO('T', 1)
+#define TTYTAP_GETDEV _IO('T', 2)
+#define TTYTAP_SETQLEN _IO('T', 3)
+#define TTYTAP_GETQLEN _IO('T', 4)
+
+typedef struct {
+ int io;
+ int len;
+ struct timeval stamp;
+} tapheader;
+
+#endif
--- linux/Documentation/Configure.help Mon Dec 11 01:49:41 2000
+++ linux-2.2.16/Documentation/Configure.help Tue Jan 30 17:55:33 2001
@@ -13506,6 +13506,19 @@
another UltraSPARC-IIi-cEngine boardset with digital display,
you should say N to this option.
+Tty tapping
+CONFIG_TTYTAP
+ Enable this if you want to analyze traffic on serial lines.
+ You will get a special file /proc/ttytap which can be used
+ from userlevel to record all data that goes thru a specified
+ tty.
+
+ WARNING:
+ Although /proc/ttytap is readable by root only, on multi-user
+ systems, this may be a security hole since root has the ability
+ to easily grab anything (including passwords) that was typed at
+ any tty. Users who care about security, therefore should say N here.
+
#
# A couple of things I keep forgetting:
# capitalize: AppleTalk, Ethernet, DOS, DMA, FAT, FTP, Internet,
--- linux/drivers/char/Config.in Mon Dec 11 01:49:41 2000
+++ linux-2.2.16/drivers/char/Config.in Tue Jan 30 17:57:25 2001
@@ -5,6 +5,7 @@
comment 'Character devices'
bool 'Virtual terminal' CONFIG_VT
+bool 'Tty tapping' CONFIG_TTYTAP
if [ "$CONFIG_VT" = "y" ]; then
bool 'Support for console on virtual terminal' CONFIG_VT_CONSOLE
fi
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