From: Ahmad Fatoum <ahmad@a3f.at>
To: barebox@lists.infradead.org
Subject: [PATCH v1 1/4] console: disallow opening for writing when no write method defined
Date: Fri, 20 Sep 2019 09:58:10 +0200 [thread overview]
Message-ID: <20190920075813.22471-1-ahmad@a3f.at> (raw)
Some consoles, like the input console (usually /dev/cs0), don't feature
a puts or putc callback. Trying to echo out of them would thus crash:
barebox@Embest MarS Board i.MX6Dual:/ echo -a /dev/cs0
prefetch abort
pc : [<00000004>] lr : [<4fd05071>]
WARNING: [<...>] (fops_write+0xd/0x10)
WARNING: [<...>] (devfs_write+0x21/0x2a)
WARNING: [<...>] (__write+0xcb/0xf0)
WARNING: [<...>] (write+0x2d/0x68)
WARNING: [<...>] (dputc+0x31/0x34)
WARNING: [<...>] (do_echo+0xcb/0x144)
Fix this by only allowing open(.., O_WRONLY) or open(..., O_RDWR) when
puts is defined. Consoles defining putc are covered by this as well as
those have putc-calling __console_puts assigned as their puts when they
are registered. Now echo -a /dev/cs0 would yield:
open: Operation not permitted
Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
common/console.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/common/console.c b/common/console.c
index d04aae58f96e..e6e029848d41 100644
--- a/common/console.c
+++ b/common/console.c
@@ -272,6 +272,9 @@ static int fops_open(struct cdev *cdev, unsigned long flags)
{
struct console_device *priv = cdev->priv;
+ if ((flags & (O_WRONLY | O_RDWR)) && !priv->puts )
+ return -EPERM;
+
return console_open(priv);
}
--
2.20.1
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next reply other threads:[~2019-09-20 7:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-20 7:58 Ahmad Fatoum [this message]
2019-09-20 7:58 ` [PATCH v1 2/4] input: set console input name as input Ahmad Fatoum
2019-09-20 7:58 ` [PATCH v1 3/4] common: ubsan: ignore shifting one into sign bit Ahmad Fatoum
2019-09-21 7:47 ` Rouven Czerwinski
2019-09-21 10:59 ` Ahmad Fatoum
2019-09-20 7:58 ` [PATCH v1 4/4] USB: gadget: ACM: don't announce V.25ter support Ahmad Fatoum
2019-09-20 8:51 ` Ahmad Fatoum
2019-09-21 11:00 ` Ahmad Fatoum
2019-09-23 6:59 ` [PATCH v1 1/4] console: disallow opening for writing when no write method defined Sascha Hauer
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