Revision 73223e4e2e3867ebf033a5a8eb2e5df0158ccc99 authored by zhong jiang on 18 August 2017, 22:16:24 UTC, committed by Linus Torvalds on 18 August 2017, 22:32:02 UTC
I hit a use after free issue when executing trinity and repoduced it with KASAN enabled. The related call trace is as follows. BUG: KASan: use after free in SyS_get_mempolicy+0x3c8/0x960 at addr ffff8801f582d766 Read of size 2 by task syz-executor1/798 INFO: Allocated in mpol_new.part.2+0x74/0x160 age=3 cpu=1 pid=799 __slab_alloc+0x768/0x970 kmem_cache_alloc+0x2e7/0x450 mpol_new.part.2+0x74/0x160 mpol_new+0x66/0x80 SyS_mbind+0x267/0x9f0 system_call_fastpath+0x16/0x1b INFO: Freed in __mpol_put+0x2b/0x40 age=4 cpu=1 pid=799 __slab_free+0x495/0x8e0 kmem_cache_free+0x2f3/0x4c0 __mpol_put+0x2b/0x40 SyS_mbind+0x383/0x9f0 system_call_fastpath+0x16/0x1b INFO: Slab 0xffffea0009cb8dc0 objects=23 used=8 fp=0xffff8801f582de40 flags=0x200000000004080 INFO: Object 0xffff8801f582d760 @offset=5984 fp=0xffff8801f582d600 Bytes b4 ffff8801f582d750: ae 01 ff ff 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ Object ffff8801f582d760: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff8801f582d770: 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkk. Redzone ffff8801f582d778: bb bb bb bb bb bb bb bb ........ Padding ffff8801f582d8b8: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ Memory state around the buggy address: ffff8801f582d600: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801f582d680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801f582d700: fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb fc !shared memory policy is not protected against parallel removal by other thread which is normally protected by the mmap_sem. do_get_mempolicy, however, drops the lock midway while we can still access it later. Early premature up_read is a historical artifact from times when put_user was called in this path see https://lwn.net/Articles/124754/ but that is gone since 8bccd85ffbaf ("[PATCH] Implement sys_* do_* layering in the memory policy layer."). but when we have the the current mempolicy ref count model. The issue was introduced accordingly. Fix the issue by removing the premature release. Link: http://lkml.kernel.org/r/1502950924-27521-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang <zhongjiang@huawei.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> [2.6+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent da094e4
build_OID_registry
#!/usr/bin/perl -w
#
# Build a static ASN.1 Object Identified (OID) registry
#
# Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
# Written by David Howells (dhowells@redhat.com)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public Licence
# as published by the Free Software Foundation; either version
# 2 of the Licence, or (at your option) any later version.
#
use strict;
my @names = ();
my @oids = ();
if ($#ARGV != 1) {
print STDERR "Format: ", $0, " <in-h-file> <out-c-file>\n";
exit(2);
}
#
# Open the file to read from
#
open IN_FILE, "<$ARGV[0]" || die;
while (<IN_FILE>) {
chomp;
if (m!\s+OID_([a-zA-z][a-zA-Z0-9_]+),\s+/[*]\s+([012][.0-9]*)\s+[*]/!) {
push @names, $1;
push @oids, $2;
}
}
close IN_FILE || die;
#
# Open the files to write into
#
open C_FILE, ">$ARGV[1]" or die;
print C_FILE "/*\n";
print C_FILE " * Automatically generated by ", $0, ". Do not edit\n";
print C_FILE " */\n";
#
# Split the data up into separate lists and also determine the lengths of the
# encoded data arrays.
#
my @indices = ();
my @lengths = ();
my $total_length = 0;
for (my $i = 0; $i <= $#names; $i++) {
my $name = $names[$i];
my $oid = $oids[$i];
my @components = split(/[.]/, $oid);
# Determine the encoded length of this OID
my $size = $#components;
for (my $loop = 2; $loop <= $#components; $loop++) {
my $c = $components[$loop];
# We will base128 encode the number
my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
$tmp = int($tmp / 7);
$size += $tmp;
}
push @lengths, $size;
push @indices, $total_length;
$total_length += $size;
}
#
# Emit the look-up-by-OID index table
#
print C_FILE "\n";
if ($total_length <= 255) {
print C_FILE "static const unsigned char oid_index[OID__NR + 1] = {\n";
} else {
print C_FILE "static const unsigned short oid_index[OID__NR + 1] = {\n";
}
for (my $i = 0; $i <= $#names; $i++) {
print C_FILE "\t[OID_", $names[$i], "] = ", $indices[$i], ",\n"
}
print C_FILE "\t[OID__NR] = ", $total_length, "\n";
print C_FILE "};\n";
#
# Encode the OIDs
#
my @encoded_oids = ();
for (my $i = 0; $i <= $#names; $i++) {
my @octets = ();
my @components = split(/[.]/, $oids[$i]);
push @octets, $components[0] * 40 + $components[1];
for (my $loop = 2; $loop <= $#components; $loop++) {
my $c = $components[$loop];
# Base128 encode the number
my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
$tmp = int($tmp / 7);
for (; $tmp > 0; $tmp--) {
push @octets, (($c >> $tmp * 7) & 0x7f) | 0x80;
}
push @octets, $c & 0x7f;
}
push @encoded_oids, \@octets;
}
#
# Create a hash value for each OID
#
my @hash_values = ();
for (my $i = 0; $i <= $#names; $i++) {
my @octets = @{$encoded_oids[$i]};
my $hash = $#octets;
foreach (@octets) {
$hash += $_ * 33;
}
$hash = ($hash >> 24) ^ ($hash >> 16) ^ ($hash >> 8) ^ ($hash);
push @hash_values, $hash & 0xff;
}
#
# Emit the OID data
#
print C_FILE "\n";
print C_FILE "static const unsigned char oid_data[", $total_length, "] = {\n";
for (my $i = 0; $i <= $#names; $i++) {
my @octets = @{$encoded_oids[$i]};
print C_FILE "\t";
print C_FILE $_, ", " foreach (@octets);
print C_FILE "\t// ", $names[$i];
print C_FILE "\n";
}
print C_FILE "};\n";
#
# Build the search index table (ordered by length then hash then content)
#
my @index_table = ( 0 .. $#names );
@index_table = sort {
my @octets_a = @{$encoded_oids[$a]};
my @octets_b = @{$encoded_oids[$b]};
return $hash_values[$a] <=> $hash_values[$b]
if ($hash_values[$a] != $hash_values[$b]);
return $#octets_a <=> $#octets_b
if ($#octets_a != $#octets_b);
for (my $i = $#octets_a; $i >= 0; $i--) {
return $octets_a[$i] <=> $octets_b[$i]
if ($octets_a[$i] != $octets_b[$i]);
}
return 0;
} @index_table;
#
# Emit the search index and hash value table
#
print C_FILE "\n";
print C_FILE "static const struct {\n";
print C_FILE "\tunsigned char hash;\n";
if ($#names <= 255) {
print C_FILE "\tenum OID oid : 8;\n";
} else {
print C_FILE "\tenum OID oid : 16;\n";
}
print C_FILE "} oid_search_table[OID__NR] = {\n";
for (my $i = 0; $i <= $#names; $i++) {
my @octets = @{$encoded_oids[$index_table[$i]]};
printf(C_FILE "\t[%3u] = { %3u, OID_%-35s }, // ",
$i,
$hash_values[$index_table[$i]],
$names[$index_table[$i]]);
printf C_FILE "%02x", $_ foreach (@octets);
print C_FILE "\n";
}
print C_FILE "};\n";
#
# Emit the OID debugging name table
#
#print C_FILE "\n";
#print C_FILE "const char *const oid_name_table[OID__NR + 1] = {\n";
#
#for (my $i = 0; $i <= $#names; $i++) {
# print C_FILE "\t\"", $names[$i], "\",\n"
#}
#print C_FILE "\t\"Unknown-OID\"\n";
#print C_FILE "};\n";
#
# Polish off
#
close C_FILE or die;
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