diff options
| author | Greg Kroah-Hartman <greg@kroah.com> | 2018-10-04 11:06:14 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-01 09:46:41 +0100 |
| commit | 2b7e9180b4017a28867f27786266cbd4e4a7cf8b (patch) | |
| tree | 29de1efb302c94212dba016b67c05ae4ce8e9c2f /drivers/tty | |
| parent | d196147ecf0951e15db959cac24d0ce8695a1897 (diff) | |
tty: wipe buffer if not echoing data
commit b97b3d9fb57860a60592859e332de7759fd54c2e upstream.
If we are not echoing the data to userspace or the console is in icanon
mode, then perhaps it is a "secret" so we should wipe it once we are
done with it.
This mirrors the logic that the audit code has.
Reported-by: aszlig <aszlig@nix.build>
Tested-by: Milan Broz <gmazyland@gmail.com>
Tested-by: Daniel Zatovic <daniel.zatovic@gmail.com>
Tested-by: aszlig <aszlig@nix.build>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/n_tty.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index b1ec202099b2..b74de014cef1 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -165,15 +165,29 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x, return put_user(x, ptr); } +/* If we are not echoing the data, perhaps this is a secret so erase it */ +static inline void zero_buffer(struct tty_struct *tty, u8 *buffer, int size) +{ + bool icanon = !!L_ICANON(tty); + bool no_echo = !L_ECHO(tty); + + if (icanon && no_echo) + memset(buffer, 0x00, size); +} + static inline int tty_copy_to_user(struct tty_struct *tty, void __user *to, - const void *from, + void *from, unsigned long n) { struct n_tty_data *ldata = tty->disc_data; + int retval; tty_audit_add_data(tty, from, n, ldata->icanon); - return copy_to_user(to, from, n); + retval = copy_to_user(to, from, n); + if (!retval) + zero_buffer(tty, from, n); + return retval; } /** @@ -2005,6 +2019,7 @@ static int copy_from_read_buf(struct tty_struct *tty, is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty); tty_audit_add_data(tty, read_buf_addr(ldata, tail), n, ldata->icanon); + zero_buffer(tty, read_buf_addr(ldata, tail), n); smp_store_release(&ldata->read_tail, ldata->read_tail + n); /* Turn single EOF into zero-length read */ if (L_EXTPROC(tty) && ldata->icanon && is_eof && |