linux-kernel - [PATCH] Compile-time check re world-writeable module params

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20061029225804.GB9197@martell.zuzino.mipt.ru>
Date:	Mon, 30 Oct 2006 01:58:04 +0300
From:	Alexey Dobriyan <adobriyan@...il.com>
To:	Andrew Morton <akpm@...l.org>
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH] Compile-time check re world-writeable module params

One of mistakes module_param() user can make is to supply default value
of module parameter as the last argument. module_param() accepts
permissions instead. If default value is, say, 3 (-------wx), parameter
becomes world-writeable.

So far, the only remedy was to apply grep(1) and read drivers submitted
to -mm. BTDT.

With this patch applied, compiler will finally do some job.

*) bounds checking on permissions
*) world-writeable bit checking on permissions
*) compile breakage if checks trigger

First version of this check (only "& 2" part) directly caught 4 out of 7
places during my last grep.

    Subject: Neverending module_param() bugs
    [X] drivers/acpi/sbs.c:101:module_param(capacity_mode, int, CAPACITY_UNIT);
    [X] drivers/acpi/sbs.c:102:module_param(update_mode, int, UPDATE_MODE);
    [ ] drivers/acpi/sbs.c:103:module_param(update_info_mode, int, UPDATE_INFO_MODE);
    [ ] drivers/acpi/sbs.c:104:module_param(update_time, int, UPDATE_TIME);
    [ ] drivers/acpi/sbs.c:105:module_param(update_time2, int, UPDATE_TIME2);
    [X] drivers/char/watchdog/sbc8360.c:203:module_param(timeout, int, 27);
    [X] drivers/media/video/tuner-simple.c:13:module_param(offset, int, 0666);

Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
---

 include/linux/moduleparam.h |    3 +++
 1 file changed, 3 insertions(+)

--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -63,6 +63,9 @@ struct kparam_array
    not there, read bits mean it's readable, write bits mean it's
    writable. */
 #define __module_param_call(prefix, name, set, get, arg, perm)		\
+	/* Default value instead of permissions? */			\
+	static int __param_perm_check_##name __attribute__((unused)) =	\
+	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2));	\
 	static char __param_str_##name[] = prefix #name;		\
 	static struct kernel_param const __param_##name			\
 	__attribute_used__						\

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/