Hi Tony,
I saw a few patches floating around regarding world writeable sysfs
files and decided to grep around arch/arm/*omap* to try and see if we
were safe. Turns out anyone can change MUX entries via the debugfs
interface:
static void __init omap_mux_dbg_create_entry(
struct omap_mux_partition *partition,
struct dentry *mux_dbg_dir)
{
struct omap_mux_entry *e;
list_for_each_entry(e, &partition->muxmodes, node) {
struct omap_mux *m = &e->mux;
(void)debugfs_create_file(m->muxnames[0], S_IWUGO, mux_dbg_dir,
m, &omap_mux_dbg_signal_fops);
}
}
is that really expected ? I guess not, attached there's a small patch to
fix that one.
--
balbi
>From d3e0b6d3ddd82b1f9ab0299105cb8bf29d142ac4 Mon Sep 17 00:00:00 2001
From: Felipe Balbi <balbi@xxxxxx>
Date: Fri, 4 Feb 2011 14:42:16 +0200
Subject: [PATCH] arm: omap2: fix a world writeable debugfs file
Organization: Texas Instruments\n
don't allow anyone to fiddle with the mux settings.
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---
arch/arm/mach-omap2/mux.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/arm/mach-omap2/mux.c b/arch/arm/mach-omap2/mux.c
index fae49d1..2727e58 100644
--- a/arch/arm/mach-omap2/mux.c
+++ b/arch/arm/mach-omap2/mux.c
@@ -605,7 +605,7 @@ static void __init omap_mux_dbg_create_entry(
list_for_each_entry(e, &partition->muxmodes, node) {
struct omap_mux *m = &e->mux;
- (void)debugfs_create_file(m->muxnames[0], S_IWUGO, mux_dbg_dir,
+ (void)debugfs_create_file(m->muxnames[0], S_IWUSR, mux_dbg_dir,
m, &omap_mux_dbg_signal_fops);
}
}
--
1.7.4.rc2
