The patch titled
make reading /proc/sys/kernel/cap-bould not require CAP_SYS_MODULE
has been added to the -mm tree. Its filename is
make-reading-proc-sys-kernel-cap-bould-not-require.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: make reading /proc/sys/kernel/cap-bould not require CAP_SYS_MODULE
From: Eric Paris <eparis@xxxxxxxxxx>
Reading /proc/sys/kernel/cap-bound requires CAP_SYS_MODULE. (see
proc_dointvec_bset in kernel/sysctl.c)
sysctl appears to drive all over proc reading everything it can get it's
hands on and is complaining when it is being denied access to read
cap-bound. Clearly writing to cap-bound should be a sensitive operation
but requiring CAP_SYS_MODULE to read cap-bound seems a bit to strong. I
believe the information could with reasonable certainty be obtained by
looking at a bunch of the output of /proc/pid/status which has very low
security protection, so at best we are just getting a little obfuscation of
information.
Currently SELinux policy has to 'dontaudit' capability checks for
CAP_SYS_MODULE for things like sysctl which just want to read cap-bound.
In doing so we also as a byproduct have to hide warnings of potential
exploits such as if at some time that sysctl actually tried to load a
module. I wondered if anyone would have a problem opening cap-bound up to
read from anyone?
Cc: Chris Wright <chrisw@xxxxxxxxxxxx>
Cc: Stephen Smalley <sds@xxxxxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/sysctl.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
diff -puN kernel/sysctl.c~make-reading-proc-sys-kernel-cap-bould-not-require kernel/sysctl.c
--- a/kernel/sysctl.c~make-reading-proc-sys-kernel-cap-bould-not-require
+++ a/kernel/sysctl.c
@@ -1961,7 +1961,7 @@ int proc_dointvec_bset(ctl_table *table,
{
int op;
- if (!capable(CAP_SYS_MODULE)) {
+ if (write && !capable(CAP_SYS_MODULE)) {
return -EPERM;
}
_
Patches currently in -mm which might be from eparis@xxxxxxxxxx are
make-reading-proc-sys-kernel-cap-bould-not-require.patch
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