4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Zev Weiss zev@bewilderbeest.net
commit 8cf7630b29701d364f8df4a50e4f1f5e752b2778 upstream.
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().
Link: http://lkml.kernel.org/r/20190207123426.9202-3-zev@bewilderbeest.net Signed-off-by: Zev Weiss zev@bewilderbeest.net Cc: Brendan Higgins brendanhiggins@google.com Cc: Iurii Zaikin yzaikin@google.com Cc: Kees Cook keescook@chromium.org Cc: Luis Chamberlain mcgrof@kernel.org Cc: stable@vger.kernel.org [2.6.2+] Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/sysctl.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
--- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2377,7 +2377,16 @@ static int do_proc_dointvec_minmax_conv( { 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;