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Add a new sysctl: kern.tty_inq_flush_secure.

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When enabled all TTY input queue buffers are zeroed when flushing or
closing the TTY. Because TTY input queues are also used to store filled
in passwords, this may be an interesting switch to enable for security
minded people.
This commit is contained in:
Ed Schouten 2009-05-21 16:19:54 +00:00
parent d422da9a0a
commit 770c15f60f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=192544
1 changed files with 8 additions and 14 deletions
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22
sys/kern/tty_inq.c
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@ -68,6 +68,9 @@ SYSCTL_ULONG(_kern, OID_AUTO, tty_inq_nfast, CTLFLAG_RD,
static unsigned long ttyinq_nslow = 0;
SYSCTL_ULONG(_kern, OID_AUTO, tty_inq_nslow, CTLFLAG_RD,
&ttyinq_nslow, 0, "Buffered reads to userspace on input");
static int ttyinq_flush_secure = 0;
SYSCTL_INT(_kern, OID_AUTO, tty_inq_flush_secure, CTLFLAG_RW,
&ttyinq_flush_secure, 0, "Zero buffers while flushing");
#define TTYINQ_QUOTESIZE (TTYINQ_DATASIZE / BMSIZE)
#define BMSIZE 32
@ -376,28 +379,19 @@ ttyinq_findchar(struct ttyinq *ti, const char *breakc, size_t maxlen,
void
ttyinq_flush(struct ttyinq *ti)
{
struct ttyinq_block *tib = ti->ti_lastblock;
ti->ti_begin = 0;
ti->ti_linestart = 0;
ti->ti_reprint = 0;
ti->ti_end = 0;
}
#if 0
void
ttyinq_flush_safe(struct ttyinq *ti)
{
struct ttyinq_block *tib;
ttyinq_flush(ti);
/* Zero all data in the input queue to make it more safe */
TAILQ_FOREACH(tib, &ti->ti_list, tib_list) {
bzero(&tib->tib_quotes, sizeof tib->tib_quotes);
bzero(&tib->tib_data, sizeof tib->tib_data);
/* Zero all data in the input queue to get rid of passwords. */
if (ttyinq_flush_secure) {
for (tib = ti->ti_firstblock; tib != NULL; tib = tib->tib_next)
bzero(&tib->tib_data, sizeof tib->tib_data);
}
}
#endif
int
ttyinq_peekchar(struct ttyinq *ti, char *c, int *quote)