From: Heinrich Schuchardt <xypron.glpk@gmx.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Nazarewicz <mina86@mina86.com>,
Ingo Molnar <mingo@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Joe Perches <joe@perches.com>, Josh Hunt <johunt@akamai.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Rusty Russell <rusty@rustcorp.com.au>,
Daniel Walter <dwalter@google.com>,
David Rientjes <rientjes@google.com>,
Kees Cook <keescook@chromium.org>,
"David S. Miller" <davem@davemloft.net>,
Johannes Weiner <hannes@cmpxchg.org>,
Aaron Tomlin <atomlin@redhat.com>,
Prarit Bhargava <prarit@redhat.com>,
Eric B Munson <emunson@akamai.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Sam Ravnborg <sam@ravnborg.org>,
linux-kernel@vger.kernel.org,
Alexey Dobriyan <adobriyan@gmail.com>
Subject: Fwd: [PATCH 3/3] sysctl: detect overflows when converting to int
Date: Tue, 31 Mar 2015 19:12:59 +0200 [thread overview]
Message-ID: <551AD59B.8060906@gmx.de> (raw)
In-Reply-To: <1427657309-4344-4-git-send-email-xypron.glpk@gmx.de>
Hello Andrew,
could you, please, propagate the patch in
https://lkml.org/lkml/2015/3/29/189
to the MM tree.
It is independent of the other two patches in the patch series.
Rework for the other patches was requested by Alexey Dobriyan in
https://lkml.org/lkml/2015/3/31/251
Best regards
Heinrich Schuchardt
On 29.03.2015 21:28, Heinrich Schuchardt wrote:
> When converting unsigned long to int overflows may occur.
> These currently are not detected when writing to the sysctl
> file system.
>
> E.g. on a system where int has 32 bits and long has 64 bits
> echo 0x800001234 > /proc/sys/kernel/threads-max
> has the same effect as
> echo 0x1234 > /proc/sys/kernel/threads-max
>
> The patch adds the missing check in do_proc_dointvec_conv.
>
> With the patch an overflow will result in an error EINVAL when
> writing to the the sysctl file system.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
> ---
> kernel/sysctl.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 4d9d139..2fd6b82 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -1953,7 +1953,15 @@ static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
> int write, void *data)
> {
> if (write) {
> - *valp = *negp ? -*lvalp : *lvalp;
> + if (*negp) {
> + if (*lvalp > (unsigned long) INT_MAX + 1)
> + return -EINVAL;
> + *valp = -*lvalp;
> + } else {
> + if (*lvalp > (unsigned long) INT_MAX)
> + return -EINVAL;
> + *valp = *lvalp;
> + }
> } else {
> int val = *valp;
> if (val < 0) {
>
next prev parent reply other threads:[~2015-03-31 17:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-29 19:28 [PATCH 0/3] sysctl: detect overflows when setting integers Heinrich Schuchardt
2015-03-29 19:28 ` [PATCH 1/3] lib/kstrtox.c: functions returning end of string Heinrich Schuchardt
2015-03-29 19:28 ` [PATCH 2/3] sysctl: detect overflows in proc_get_long Heinrich Schuchardt
2015-03-29 19:28 ` [PATCH 3/3] sysctl: detect overflows when converting to int Heinrich Schuchardt
2015-03-31 17:12 ` Heinrich Schuchardt [this message]
2015-03-31 22:45 ` Andrew Morton
2015-04-01 17:31 ` Heinrich Schuchardt
2015-06-08 22:41 ` Kees Cook
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