Messages in this thread Patches in this message | | | Date | Thu, 02 Sep 2010 16:06:16 +0200 | From | Nathael Pajani <> | Subject | [PATCH 1/1] tty : fix tty_line must not be equal to number of allocated tty pointers in tty driver |
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Hi,
I found a bug "by chance" in drivers/char/tty_io.c
I mean "by chance" because I was just reading the code of the tty_find_polling_driver() to make a new tty_find_by_name() function.
--- In tty_find_polling_driver() the driver actually test "tty_line <= p->num" while num refers to the number of struct tty_struct pointers allocated for the p->ttys (p is a tty_driver), and tty_line is scanned in a tty name, which can be for example ttyS2. Then tty_line equals 2. And if p->num is 2, we have only p->ttys[0] and p->ttys[1], but no p->ttys[2].
This is actually unharmful, for tty_find_polling_driver() is used only in drivers/serial/kgdboc.c, and there's a test over there to find a console with a matching index, which will never happen.
This is still a bug anyway.
Signed-off-by: Nathael Pajani <nathael.pajani@ed3l.fr> ---
patch against 2bfc96a127bc1cc94d26bfaa40159966064f9c8c (Linux 2.6.36-rc3) :
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 949067a..613c852 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -355,7 +355,7 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line) if (*stp == '\0') stp = NULL;
- if (tty_line >= 0 && tty_line <= p->num && p->ops && + if (tty_line >= 0 && tty_line < p->num && p->ops && p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) { res = tty_driver_kref_get(p); *line = tty_line;
Have fun. +++ -- Nathaël PAJANI ED3L - Etude et Développement - Linux et Logiciels Libres Internet : http://www.ed3l.fr diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 949067a..613c852 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -355,7 +355,7 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line) if (*stp == '\0') stp = NULL; - if (tty_line >= 0 && tty_line <= p->num && p->ops && + if (tty_line >= 0 && tty_line < p->num && p->ops && p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) { res = tty_driver_kref_get(p); *line = tty_line; | |