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From: Zev Weiss <zev@bewilderbeest.net>
To: Luis Chamberlain <mcgrof@kernel.org>, Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	yzaikin@google.com, brendanhiggins@google.com,
	Zev Weiss <zev@bewilderbeest.net>,
	stable@vger.kernel.org
Subject: [PATCH v2 2/3] kernel/sysctl.c: add missing range check in do_proc_dointvec_minmax_conv
Date: Thu,  7 Feb 2019 06:34:25 -0600
Message-ID: <20190207123426.9202-3-zev@bewilderbeest.net> (raw)
In-Reply-To: <20190207123426.9202-1-zev@bewilderbeest.net>

This bug has apparently existed since the introduction of this function
in the pre-git era (4500e91754d3 in Thomas Gleixner's history.git,
"[NET]: Add proc_dointvec_userhz_jiffies, use it for proper handling of
neighbour sysctls.").  As a minimal fix we can simply duplicate the
corresponding check in do_proc_dointvec_conv().

Cc: <stable@vger.kernel.org> # v2.6.2+
Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
---
 kernel/sysctl.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 5fc724e4e454..a71c4b3935bc 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2564,7 +2564,16 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
 {
 	struct do_proc_dointvec_minmax_conv_param *param = data;
 	if (write) {
-		int val = *negp ? -*lvalp : *lvalp;
+		int val;
+		if (*negp) {
+			if (*lvalp > (unsigned long) INT_MAX + 1)
+				return -EINVAL;
+			val = -*lvalp;
+		} else {
+			if (*lvalp > (unsigned long) INT_MAX)
+				return -EINVAL;
+			val = *lvalp;
+		}
 		if ((param->min && *param->min > val) ||
 		    (param->max && *param->max < val))
 			return -EINVAL;
-- 
2.20.1


  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-27 11:12 [PATCH 0/2] sysctl: fix range-checking in do_proc_dointvec_minmax_conv() Zev Weiss
2018-12-27 11:12 ` [PATCH 1/2] test_sysctl: add tests for >32-bit values written to 32-bit integers Zev Weiss
2018-12-27 11:12 ` [PATCH 2/2] kernel/sysctl.c: define minmax conv functions in terms of non-minmax versions Zev Weiss
2019-02-06 19:58   ` Luis Chamberlain
2019-02-07 12:34     ` [PATCH v2 0/3] sysctl: fix range-checking in do_proc_dointvec_minmax_conv() Zev Weiss
2019-02-07 12:34       ` [PATCH v2 1/3] test_sysctl: add tests for >32-bit values written to 32-bit integers Zev Weiss
2019-02-07 12:34       ` Zev Weiss [this message]
2019-02-07 12:34       ` [PATCH v2 3/3] kernel/sysctl.c: define minmax conv functions in terms of non-minmax versions Zev Weiss
2019-02-07 15:51       ` [PATCH v2 0/3] sysctl: fix range-checking in do_proc_dointvec_minmax_conv() Luis Chamberlain
2019-02-07 16:54         ` Zev Weiss
2019-02-07 16:51       ` [PATCH v2 3/3] kernel/sysctl.c: define minmax conv functions in terms of non-minmax versions Zev Weiss
2019-02-05 16:23 ` [PATCH 0/2] sysctl: fix range-checking in do_proc_dointvec_minmax_conv() Zev Weiss

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