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Daniel Borkmann 67c05d9414 bpf, array: fix overflow in max_entries and undefined behavior in index_mask
commit bbeb6e4323 upstream.

syzkaller tried to alloc a map with 0xfffffffd entries out of a userns,
and thus unprivileged. With the recently added logic in b2157399cc
("bpf: prevent out-of-bounds speculation") we round this up to the next
power of two value for max_entries for unprivileged such that we can
apply proper masking into potentially zeroed out map slots.

However, this will generate an index_mask of 0xffffffff, and therefore
a + 1 will let this overflow into new max_entries of 0. This will pass
allocation, etc, and later on map access we still enforce on the original
attr->max_entries value which was 0xfffffffd, therefore triggering GPF
all over the place. Thus bail out on overflow in such case.

Moreover, on 32 bit archs roundup_pow_of_two() can also not be used,
since fls_long(max_entries - 1) can result in 32 and 1UL << 32 in 32 bit
space is undefined. Therefore, do this by hand in a 64 bit variable.

This fixes all the issues triggered by syzkaller's reproducers.

Fixes: b2157399cc ("bpf: prevent out-of-bounds speculation")
Reported-by: syzbot+b0efb8e572d01bce1ae0@syzkaller.appspotmail.com
Reported-by: syzbot+6c15e9744f75f2364773@syzkaller.appspotmail.com
Reported-by: syzbot+d2f5524fb46fd3b312ee@syzkaller.appspotmail.com
Reported-by: syzbot+61d23c95395cc90dbc2b@syzkaller.appspotmail.com
Reported-by: syzbot+0d363c942452cca68c01@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2018-01-17 09:45:25 +01:00
arch KVM: PPC: Book3S HV: Always flush TLB in kvmppc_alloc_reset_hpt() 2018-01-17 09:45:24 +01:00
block block: don't let passthrough IO go into .make_request_fn() 2018-01-02 20:31:05 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: algapi - fix NULL dereference in crypto_remove_spawns() 2018-01-17 09:45:23 +01:00
Documentation x86/kaslr: Fix the vaddr_end mess 2018-01-10 09:31:16 +01:00
drivers drm/i915: Fix init_clock_gating for resume 2018-01-17 09:45:25 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs x86 / CPU: Always show current CPU frequency in /proc/cpuinfo 2018-01-10 09:31:20 +01:00
include bpf: prevent out-of-bounds speculation 2018-01-17 09:45:25 +01:00
init x86/mm/pti: Add infrastructure for page table isolation 2018-01-02 20:30:56 +01:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel bpf, array: fix overflow in max_entries and undefined behavior in index_mask 2018-01-17 09:45:25 +01:00
lib x86/unwind: Rename unwinder config options to 'CONFIG_UNWINDER_*' 2017-12-25 14:26:13 +01:00
mm mm/sparse.c: wrong allocation for mem_section 2018-01-10 09:31:17 +01:00
net ipv6: sr: fix TLVs not being copied using setsockopt 2018-01-17 09:45:23 +01:00
samples samples/bpf: adjust rlimit RLIMIT_MEMLOCK for xdp1 2017-12-20 10:10:31 +01:00
scripts linux/compiler.h: Split into compiler.h and compiler_types.h 2017-12-25 14:26:33 +01:00
security apparmor: fix regression in mount mediation when feature set is pinned 2018-01-10 09:31:22 +01:00
sound ALSA: aloop: Fix racy hw constraints adjustment 2018-01-17 09:45:20 +01:00
tools usbip: fix usbip bind writing random string after command in match_busid 2018-01-02 20:31:13 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: Fix stack-out-of-bounds read in write_mmio 2018-01-17 09:45:17 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2017-11-09 18:26:51 -08:00
Makefile Linux 4.14.13 2018-01-10 09:31:23 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.