The size of the ipkgs increase a bit (between 0.7% and 1.1%):
old 2019-04-21 (2.8):
288264 wpad-basic_2019-04-21-63962824-1_mipsel_24kc.ipk
256188 wpad-mini_2019-04-21-63962824-1_mipsel_24kc.ipk
427475 wpad-openssl_2019-04-21-63962824-1_mipsel_24kc.ipk
423071 wpad-wolfssl_2019-04-21-63962824-1_mipsel_24kc.ipk
new 2019-08-08 (2.9):
290217 wpad-basic_2019-08-08-ca8c2bd2-1_mipsel_24kc.ipk
258745 wpad-mini_2019-08-08-ca8c2bd2-1_mipsel_24kc.ipk
431732 wpad-openssl_2019-08-08-ca8c2bd2-1_mipsel_24kc.ipk
427641 wpad-wolfssl_2019-08-08-ca8c2bd2-1_mipsel_24kc.ipk
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
This also syncs the configuration files with the default configuration
files, but no extra options are activated or deactivated.
The mesh patches were partially merged into hostapd 2.8, the remaining
patches were extracted from patchwork and are now applied by OpenWrt.
The patches still have open questions which are not fixed by the author.
They were taken from this page:
https://patchwork.ozlabs.org/project/hostap/list/?series=62725&state=*
The changes in 007-mesh-apply-channel-attributes-before-running-Mesh.patch
where first applied to hostapd, but later reverted in hostapd commit
3e949655ccc5 because they caused memory leaks.
The size of the ipkgs increase a bit (between 1.3% and 2.3%):
old 2018-12-02 (2.7):
283337 wpad-basic_2018-12-02-c2c6c01b-11_mipsel_24kc.ipk
252857 wpad-mini_2018-12-02-c2c6c01b-11_mipsel_24kc.ipk
417473 wpad-openssl_2018-12-02-c2c6c01b-11_mipsel_24kc.ipk
415105 wpad-wolfssl_2018-12-02-c2c6c01b-11_mipsel_24kc.ipk
new 2019-04-21 (2.8):
288264 wpad-basic_2019-04-21-63962824-1_mipsel_24kc.ipk
256188 wpad-mini_2019-04-21-63962824-1_mipsel_24kc.ipk
427475 wpad-openssl_2019-04-21-63962824-1_mipsel_24kc.ipk
423071 wpad-wolfssl_2019-04-21-63962824-1_mipsel_24kc.ipk
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
For AP mode, OpenWrt automatically sets ieee80211w to either 1 or 2, depending
on whether the encryption is set to sae-mixed, or sae/owe/eap suite-b.
Mirror the same defaults for client mode connections, in order to allow an
OpenWrt station to associate to an OpenWrt ap with SAE, OWE or Suite-B encryption
without the need to manually specify "option ieee80211w" on the station.
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
This changes fixes the generation of the wpa_supplicant client configuration
in WPA3 OWE client mode. Instead of incorrectly emitting key_mgmt=NONE, use
the proper key_mgmt=OWE setting instead.
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
wps_supplicant.h assumes that 'struct wpa_bss' is forward declared if
CONFIG_WPS is not defined. With the later inclusion of
600-ubus_support, the issue manifests in warnings like these:
wps_supplicant.h:113:15: warning: 'struct wpa_bss' declared inside parameter list will not be visible outside of this definition or declaration
struct wpa_bss *bss)
^~~~~~~
This patch forward declares 'struct wpa_bss' regardless.
Signed-off-by: Leon M. George <leon@georgemail.eu>
[commit message facelift]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
The original wpa_hexdump uses a 'void *' for the payload. With patch
410-limit_debug_messages, the signature changes and compiler warnings
occur at various places. One such warning is:
wpa_debug.h:106:20: note: expected 'const u8 * {aka const unsigned char *}' but argument is of type 'struct wpa_eapol_key *'
Signed-off-by: Leon M. George <leon@georgemail.eu>
[commit message facelift]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
commit eb204d14f75c ("base-files: implement generic service_running")
introduced generic service_running so it's not needed to copy&paste same
3 lines over and over again.
I've removed service_running from netifd/network init script as well,
because it was not working properly, looked quite strange and I didn't
understand the intention:
$ /etc/init.d/network stop
$ service network running && echo "yes" || echo "nope"
( have to wait for 30s )
Command failed: Request timed out
yes
Signed-off-by: Petr Štetiar <ynezz@true.cz>
e73bf11 config: ra_management compatibility support
d818380 odhcpd: router: Fix out of scope memory access
94a1c94 dhcpv6-ia: free assignment when validity timer expires
752fc2c router: speed up initial router advertisements
09aa022 router: close socket upon NETEV_IFINDEX_CHANGE fixed
79eb160 router: fix previous commit
6034b5c router: close socket upon NETEV_IFINDEX_CHANGE
000182f router: fix lingering uloop socket descriptor
f6c2242 router: support ra_lifetime being 0
d111809 router: make RA flags configurable (FS#2019)
Update odhcpd defaults according to the new RA flags implementation
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
This adds the key_type and ec_curve options to enable the generation of
EC keys during initialization, using openssl or the new options added to
px5g.
Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>
This commit will activate CONFIG_IEEE80211W for all, but the mini
variant when at least one driver supports it. This will add ieee80211w
support for the mesh variant for example.
Fixes: FS#2397
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
This changes the default PKG_BUILD_DIR to take BUILD_VARIANT into
account (if set), so that packages do not need to manually override
PKG_BUILD_DIR just to handle variants.
This also updates most base packages with variants to use the updated
default PKG_BUILD_DIR.
Signed-off-by: Jeffery To <jeffery.to@gmail.com>
Backport upstream patches pre 2.81rc for testing purposes.
Let's see what falls out!
Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
To configure the list of allowable TLS 1.3 ciphersuites, the option
tls_ciphersuites is used instead of tls_ciphers.
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
This edjusts the selection of recently removed wolfssl options which
have always been built into the library even in their abscence.
Also remove the selection of libwolfssl itself, allowing the library to
be built as a module.
Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>
This addresses an issue where the list option specified in
/etc/config/openvpn i.e. 'tls_cipher' would instead show up in the
generated openvpn-<name>.conf as 'ncp-ciphers'. For context,
'ncp_ciphers' appears after 'tls_cipher' in OPENVPN_LIST from
openvpn.options.
Also, the ordering of the options in the UCI config file is now
preserved when generating the OpenVPN config. The two currently
supported list options deal with cipher preferences.
Signed-off-by: Matt Merhar <mattmerhar@protonmail.com>
* curve25519: not all linkers support bmi2 and adx
This should allow WireGuard to build on older toolchains.
* global: switch to coarse ktime
Our prior use of fast ktime before meant that sometimes, depending on how
broken the motherboard was, we'd wind up calling into the HPET slow path. Here
we move to coarse ktime which is always super speedy. In the process we had to
fix the resolution of the clock, as well as introduce a new interface for it,
landing in 5.3. Older kernels fall back to a fast-enough mechanism based on
jiffies.
https://lore.kernel.org/lkml/tip-e3ff9c3678b4d80e22d2557b68726174578eaf52@git.kernel.org/https://lore.kernel.org/lkml/20190621203249.3909-3-Jason@zx2c4.com/
* netlink: cast struct over cb->args for type safety
This follow recent upstream changes such as:
https://lore.kernel.org/lkml/20190628144022.31376-1-Jason@zx2c4.com/
* peer: use LIST_HEAD macro
Style nit.
* receive: queue dead packets to napi queue instead of empty rx_queue
This mitigates a WARN_ON being triggered by the workqueue code. It was quite
hard to trigger, except sporadically, or reliably with a PC Engines ALIX, an
extremely slow board with an AMD LX800 that Ryan Whelan of Axatrax was kind
enough to mail me.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Support to disable the timestamp check for certificates in
wpa_supplicant (Useful for devices without RTC that cannot
reliably get the real date/time) has been accepted in the
upstream hostapd. It's implemented in wpa_supplicant as a
per-AP flag tls_disable_time_checks=[0|1].
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
The OpenWrt buildroot ABI version rebuild tracker does not handle
transient dependencies, therefor add all libraries linked by uhttpd
as direct dependencies to the corresponding binary package definition.
This ensures that uhttpd is automatically rebuilt and relinked if any
of these libraries has its ABI_VERSION updated in the future.
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
This is to make life easier for users with customized build of
dnsmasq-full variant. Currently dnsmasq config generated by current
service script will be rejected by dnsmasq build lacking DHCP feature
- Options like --dhcp-leasefile have default values. Deleting them
from uci config or setting them to empty value will make them take on
default value in the end
- Options like --dhcp-broadcast are output unconditionally
Tackle this by
- Check availablility of features from output of "dnsmasq --version"
- Make a list of options guarded by HAVE_xx macros in src/options.c of
dnsmasq source code
- Ignore these options in xappend()
Two things to note in this implementation
- The option list is not exhaustive. Supposedly only those options that
may cause dnsmasq to reject with "unsupported option (check that
dnsmasq was compiled with DHCP/TFTP/DNSSEC/DBus support)" are taken
into account here
- This provides a way out but users' cooperation is still needed. E.g.
option dnssec needs to be turned off, otherwise the service script
will try to add --conf-file pointing to dnssec specific anchor file
which dnsmasq lacking dnssec support will reject
Resolves FS#2281
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>
There was an issue with the backport compat layer in yesterday's snapshot,
causing issues on certain (mostly Atom) Intel chips on kernels older than
4.2, due to the use of xgetbv without checking cpu flags for xsave support.
This manifested itself simply at module load time. Indeed it's somewhat tricky
to support 33 different kernel versions (3.10+), plus weird distro
frankenkernels.
If OpenWRT doesn't support < 4.2, you probably don't need to apply this.
But it also can't hurt, and probably best to stay updated.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
* tools: add wincompat layer to wg(8)
Consistent with a lot of the Windows work we've been doing this last cycle,
wg(8) now supports the WireGuard for Windows app by talking through a named
pipe. You can compile this as `PLATFORM=windows make -C src/tools` with mingw.
Because programming things for Windows is pretty ugly, we've done this via a
separate standalone wincompat layer, so that we don't pollute our pretty *nix
utility.
* compat: udp_tunnel: force cast sk_data_ready
This is a hack to work around broken Android kernel wrapper scripts.
* wg-quick: freebsd: workaround SIOCGIFSTATUS race in FreeBSD kernel
FreeBSD had a number of kernel race conditions, some of which we can vaguely
work around. These are in the process of being fixed upstream, but probably
people won't update for a while.
* wg-quick: make darwin and freebsd path search strict like linux
Correctness.
* socket: set ignore_df=1 on xmit
This was intended from early on but didn't work on IPv6 without the ignore_df
flag. It allows sending fragments over IPv6.
* qemu: use newer iproute2 and kernel
* qemu: build iproute2 with libmnl support
* qemu: do not check for alignment with ubsan
The QEMU build system has been improved to compile newer versions. Linking
against libmnl gives us better error messages. As well, enabling the alignment
check on x86 UBSAN isn't realistic.
* wg-quick: look up existing routes properly
* wg-quick: specify protocol to ip(8), because of inconsistencies
The route inclusion check was wrong prior, and Linux 5.1 made it break
entirely. This makes a better invocation of `ip route show match`.
* netlink: use new strict length types in policy for 5.2
* kbuild: account for recent upstream changes
* zinc: arm64: use cpu_get_elf_hwcap accessor for 5.2
The usual churn of changes required for the upcoming 5.2.
* timers: add jitter on ack failure reinitiation
Correctness tweak in the timer system.
* blake2s,chacha: latency tweak
* blake2s: shorten ssse3 loop
In every odd-numbered round, instead of operating over the state
x00 x01 x02 x03
x05 x06 x07 x04
x10 x11 x08 x09
x15 x12 x13 x14
we operate over the rotated state
x03 x00 x01 x02
x04 x05 x06 x07
x09 x10 x11 x08
x14 x15 x12 x13
The advantage here is that this requires no changes to the 'x04 x05 x06 x07'
row, which is in the critical path. This results in a noticeable latency
improvement of roughly R cycles, for R diagonal rounds in the primitive. As
well, the blake2s AVX implementation is now SSSE3 and considerably shorter.
* tools: allow setting WG_ENDPOINT_RESOLUTION_RETRIES
System integrators can now specify things like
WG_ENDPOINT_RESOLUTION_RETRIES=infinity when building wg(8)-based init
scripts and services, or 0, or any other integer.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Upstream PPP project has added in commit 8e77984 options to tune discovery
timeout and attempts in the rp-pppoe plugin.
Expose these options in the uci datamodel for pppoe:
padi_attempts: Number of discovery attempts
padi_timeout: Initial timeout for discovery packets in seconds
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
c9d9dbf pppoe: Custom host-uniq tag
44012ae plugins/rp-pppoe: Fix compile errors
Refresh patches
Drop 520-uniq patch as upstream accepted
Drop 150-debug_compile_fix patch as fixed upstream
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
41a74cb config: remove 'ignore' config option
c0c8034 treewide: init assignment lists head
f98b7ee config: use list safe iterator in lease_delete
3c9810b dhcpv4: fix lease ordering by ip address
b60c384 config: use multi-stage parsing of uci sections
a2dd8d6 treewide: always init interface list heads during initialization
a17665e dhcpv4: do not allow pool end address to overlap with broadcast address
6b951c5 treewide: give file descriptors safe initial value
39e11ed dhcpv4: DHCP pool size is off-by-one
4a600ce dhcpv4: add support for Parameter Request List option 55
09e5eca dhcpv4: fix DHCP packet size
3cd4876 ndp: fix syslog flooding (FS#2242)
79fbba1 config: set default loglevel to LOG_WARNING
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
fcb076c Various fixes for errors found by coverity static analysis (#109)
d98ab38 Merge branch 'pppd_print_changes' of https://github.com/nlhintz/ppp into nlhintz-pppd_print_changes
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
This reverts commit c6aa9ff388.
Further testing has revealed that we will need to allow concurrent
requests after all, especially for situations where CGI processes
initiate further HTTP requests to the local host.
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
EAP-pwd missing commit validation
Published: April 10, 2019
Identifiers:
- CVE-2019-9497 (EAP-pwd server not checking for reflection attack)
- CVE-2019-9498 (EAP-pwd server missing commit validation for
scalar/element)
- CVE-2019-9499 (EAP-pwd peer missing commit validation for
scalar/element)
Latest version available from: https://w1.fi/security/2019-4/
Vulnerability
EAP-pwd implementation in hostapd (EAP server) and wpa_supplicant (EAP
peer) was discovered not to validate the received scalar and element
values in EAP-pwd-Commit messages properly. This could result in attacks
that would be able to complete EAP-pwd authentication exchange without
the attacker having to know the used password.
A reflection attack is possible against the EAP-pwd server since the
hostapd EAP server did not verify that the EAP-pwd-Commit contains
scalar/element values that differ from the ones the server sent out
itself. This allows the attacker to complete EAP-pwd authentication
without knowing the password, but this does not result in the attacker
being able to derive the session key (MSK), i.e., the attacker would not
be able to complete the following key exchange (e.g., 4-way handshake in
RSN/WPA).
An attack using invalid scalar/element values is possible against both
the EAP-pwd server and peer since hostapd and wpa_supplicant did not
validate these values in the received EAP-pwd-Commit messages. If the
used crypto library does not implement additional checks for the element
(EC point), this could result in attacks where the attacker could use a
specially crafted commit message values to manipulate the exchange to
result in deriving a session key value from a very small set of possible
values. This could further be used to attack the EAP-pwd server in a
practical manner. An attack against the EAP-pwd peer is slightly more
complex, but still consider practical. These invalid scalar/element
attacks could result in the attacker being able to complete
authentication and learn the session key and MSK to allow the key
exchange to be completed as well, i.e., the attacker gaining access to
the network in case of the attack against the EAP server or the attacker
being able to operate a rogue AP in case of the attack against the EAP
peer.
While similar attacks might be applicable against SAE, it should be
noted that the SAE implementation in hostapd and wpa_supplicant does
have the validation steps that were missing from the EAP-pwd
implementation and as such, these attacks do not apply to the current
SAE implementation. Old versions of wpa_supplicant/hostapd did not
include the reflection attack check in the SAE implementation, though,
since that was added in June 2015 for v2.5 (commit 6a58444d27fd 'SAE:
Verify that own/peer commit-scalar and COMMIT-ELEMENT are different').
Vulnerable versions/configurations
All hostapd versions with EAP-pwd support (CONFIG_EAP_PWD=y in the build
configuration and EAP-pwd being enabled in the runtime configuration)
are vulnerable against the reflection attack.
All wpa_supplicant and hostapd versions with EAP-pwd support
(CONFIG_EAP_PWD=y in the build configuration and EAP-pwd being enabled
in the runtime configuration) are vulnerable against the invalid
scalar/element attack when built against a crypto library that does not
have an explicit validation step on imported EC points. The following
list indicates which cases are vulnerable/not vulnerable:
- OpenSSL v1.0.2 or older: vulnerable
- OpenSSL v1.1.0 or newer: not vulnerable
- BoringSSL with commit 38feb990a183 ('Require that EC points are on the
curve.') from September 2015: not vulnerable
- BoringSSL without commit 38feb990a183: vulnerable
- LibreSSL: vulnerable
- wolfssl: vulnerable
Acknowledgments
Thanks to Mathy Vanhoef (New York University Abu Dhabi) for discovering
and reporting the issues and for proposing changes to address them in
the implementation.
Possible mitigation steps
- Merge the following commits to wpa_supplicant/hostapd and rebuild:
CVE-2019-9497:
EAP-pwd server: Detect reflection attacks
CVE-2019-9498:
EAP-pwd server: Verify received scalar and element
EAP-pwd: Check element x,y coordinates explicitly
CVE-2019-9499:
EAP-pwd client: Verify received scalar and element
EAP-pwd: Check element x,y coordinates explicitly
These patches are available from https://w1.fi/security/2019-4/
- Update to wpa_supplicant/hostapd v2.8 or newer, once available
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
[bump PKG_RELEASE]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
hostapd: fix SAE confirm missing state validation
Published: April 10, 2019
Identifiers:
- CVE-2019-9496 (SAE confirm missing state validation in hostapd/AP)
Latest version available from: https://w1.fi/security/2019-3/
Vulnerability
When hostapd is used to operate an access point with SAE (Simultaneous
Authentication of Equals; also known as WPA3-Personal), an invalid
authentication sequence could result in the hostapd process terminating
due to a NULL pointer dereference when processing SAE confirm
message. This was caused by missing state validation steps when
processing the SAE confirm message in hostapd/AP mode.
Similar cases against the wpa_supplicant SAE station implementation had
already been tested by the hwsim test cases, but those sequences did not
trigger this specific code path in AP mode which is why the issue was
not discovered earlier.
An attacker in radio range of an access point using hostapd in SAE
configuration could use this issue to perform a denial of service attack
by forcing the hostapd process to terminate.
Vulnerable versions/configurations
All hostapd versions with SAE support (CONFIG_SAE=y in the build
configuration and SAE being enabled in the runtime configuration).
Possible mitigation steps
- Merge the following commit to hostapd and rebuild:
SAE: Fix confirm message validation in error cases
These patches are available from https://w1.fi/security/2019-3/
- Update to hostapd v2.8 or newer, once available
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
[bump PKG_RELEASE]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
EAP-pwd side-channel attack
Published: April 10, 2019
Identifiers:
- CVE-2019-9495 (cache attack against EAP-pwd)
Latest version available from: https://w1.fi/security/2019-2/
Vulnerability
Number of potential side channel attacks were recently discovered in the
SAE implementations used by both hostapd and wpa_supplicant (see
security advisory 2019-1 and VU#871675). EAP-pwd uses a similar design
for deriving PWE from the password and while a specific attack against
EAP-pwd is not yet known to be tested, there is no reason to believe
that the EAP-pwd implementation would be immune against the type of
cache attack that was identified for the SAE implementation. Since the
EAP-pwd implementation in hostapd (EAP server) and wpa_supplicant (EAP
peer) does not support MODP groups, the timing attack described against
SAE is not applicable for the EAP-pwd implementation.
A novel cache-based attack against SAE handshake would likely be
applicable against the EAP-pwd implementation. Even though the
wpa_supplicant/hostapd PWE derivation iteration for EAP-pwd has
protections against timing attacks, this new cache-based attack might
enable an attacker to determine which code branch is taken in the
iteration if the attacker is able to run unprivileged code on the victim
machine (e.g., an app installed on a smart phone or potentially a
JavaScript code on a web site loaded by a web browser). This depends on
the used CPU not providing sufficient protection to prevent unprivileged
applications from observing memory access patterns through the shared
cache (which is the most likely case with today's designs).
The attacker could use information about the selected branch to learn
information about the password and combine this information from number
of handshake instances with an offline dictionary attack. With
sufficient number of handshakes and sufficiently weak password, this
might result in full recovery of the used password if that password is
not strong enough to protect against dictionary attacks.
This attack requires the attacker to be able to run a program on the
target device. This is not commonly the case on an authentication server
(EAP server), so the most likely target for this would be a client
device using EAP-pwd.
The commits listed in the end of this advisory change the EAP-pwd
implementation shared by hostapd and wpa_supplicant to perform the PWE
derivation loop using operations that use constant time and memory
access pattern to minimize the externally observable differences from
operations that depend on the password even for the case where the
attacker might be able to run unprivileged code on the same device.
Vulnerable versions/configurations
All wpa_supplicant and hostapd versions with EAP-pwd support
(CONFIG_EAP_PWD=y in the build configuration and EAP-pwd being enabled
in the runtime configuration).
It should also be noted that older versions of wpa_supplicant/hostapd
prior to v2.7 did not include additional protection against certain
timing differences. The definition of the EAP-pwd (RFC 5931) does not
describe such protection, but the same issue that was addressed in SAE
earlier can be applicable against EAP-pwd as well and as such, that
implementation specific extra protection (commit 22ac3dfebf7b, "EAP-pwd:
Mask timing of PWE derivation") is needed to avoid showing externally
visible timing differences that could leak information about the
password. Any uses of older wpa_supplicant/hostapd versions with EAP-pwd
are recommended to update to v2.7 or newer in addition to the mitigation
steps listed below for the more recently discovered issue.
Possible mitigation steps
- Merge the following commits to wpa_supplicant/hostapd and rebuild:
OpenSSL: Use constant time operations for private bignums
Add helper functions for constant time operations
OpenSSL: Use constant time selection for crypto_bignum_legendre()
EAP-pwd: Use constant time and memory access for finding the PWE
These patches are available from https://w1.fi/security/2019-2/
- Update to wpa_supplicant/hostapd v2.8 or newer, once available
- Use strong passwords to prevent dictionary attacks
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
[bump PKG_RELEASE]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
SAE side-channel attacks
Published: April 10, 2019
Identifiers:
- VU#871675
- CVE-2019-9494 (cache attack against SAE)
Latest version available from: https://w1.fi/security/2019-1/
Vulnerability
Number of potential side channel attacks were discovered in the SAE
implementations used by both hostapd (AP) and wpa_supplicant
(infrastructure BSS station/mesh station). SAE (Simultaneous
Authentication of Equals) is also known as WPA3-Personal. The discovered
side channel attacks may be able to leak information about the used
password based on observable timing differences and cache access
patterns. This might result in full password recovery when combined with
an offline dictionary attack and if the password is not strong enough to
protect against dictionary attacks.
Cache attack
A novel cache-based attack against SAE handshake was discovered. This
attack targets SAE with ECC groups. ECC group 19 being the mandatory
group to support and the most likely used group for SAE today, so this
attack applies to the most common SAE use case. Even though the PWE
derivation iteration in SAE has protections against timing attacks, this
new cache-based attack enables an attacker to determine which code
branch is taken in the iteration if the attacker is able to run
unprivileged code on the victim machine (e.g., an app installed on a
smart phone or potentially a JavaScript code on a web site loaded by a
web browser). This depends on the used CPU not providing sufficient
protection to prevent unprivileged applications from observing memory
access patterns through the shared cache (which is the most likely case
with today's designs).
The attacker can use information about the selected branch to learn
information about the password and combine this information from number
of handshake instances with an offline dictionary attack. With
sufficient number of handshakes and sufficiently weak password, this
might result in full discovery of the used password.
This attack requires the attacker to be able to run a program on the
target device. This is not commonly the case on access points, so the
most likely target for this would be a client device using SAE in an
infrastructure BSS or mesh BSS.
The commits listed in the end of this advisory change the SAE
implementation shared by hostapd and wpa_supplicant to perform the PWE
derivation loop using operations that use constant time and memory
access pattern to minimize the externally observable differences from
operations that depend on the password even for the case where the
attacker might be able to run unprivileged code on the same device.
Timing attack
The timing attack applies to the MODP groups 22, 23, and 24 where the
PWE generation algorithm defined for SAE can have sufficient timing
differences for an attacker to be able to determine how many rounds were
needed to find the PWE based on the used password and MAC
addresses. When the attack is repeated with multiple times, the attacker
may be able to gather enough information about the password to be able
to recover it fully using an offline dictionary attack if the password
is not strong enough to protect against dictionary attacks. This attack
could be performed by an attacker in radio range of an access point or a
station enabling the specific MODP groups.
This timing attack requires the applicable MODP groups to be enabled
explicitly in hostapd/wpa_supplicant configuration (sae_groups
parameter). All versions of hostapd/wpa_supplicant have disabled these
groups by default.
While this security advisory lists couple of commits introducing
additional protection for MODP groups in SAE, it should be noted that
the groups 22, 23, and 24 are not considered strong enough to meet the
current expectation for a secure system. As such, their use is
discouraged even if the additional protection mechanisms in the
implementation are included.
Vulnerable versions/configurations
All wpa_supplicant and hostapd versions with SAE support (CONFIG_SAE=y
in the build configuration and SAE being enabled in the runtime
configuration).
Acknowledgments
Thanks to Mathy Vanhoef (New York University Abu Dhabi) and Eyal Ronen
(Tel Aviv University) for discovering the issues and for discussions on
how to address them.
Possible mitigation steps
- Merge the following commits to wpa_supplicant/hostapd and rebuild:
OpenSSL: Use constant time operations for private bignums
Add helper functions for constant time operations
OpenSSL: Use constant time selection for crypto_bignum_legendre()
SAE: Minimize timing differences in PWE derivation
SAE: Avoid branches in is_quadratic_residue_blind()
SAE: Mask timing of MODP groups 22, 23, 24
SAE: Use const_time selection for PWE in FFC
SAE: Use constant time operations in sae_test_pwd_seed_ffc()
These patches are available from https://w1.fi/security/2019-1/
- Update to wpa_supplicant/hostapd v2.8 or newer, once available
- In addition to either of the above alternatives, disable MODP groups
1, 2, 5, 22, 23, and 24 by removing them from hostapd/wpa_supplicant
sae_groups runtime configuration parameter, if they were explicitly
enabled since those groups are not considered strong enough to meet
current security expectations. The groups 22, 23, and 24 are related
to the discovered side channel (timing) attack. The other groups in
the list are consider too weak to provide sufficient security. Note
that all these groups have been disabled by default in all
hostapd/wpa_supplicant versions and these would be used only if
explicitly enabled in the configuration.
- Use strong passwords to prevent dictionary attacks
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
[bump PKG_RELEASE]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
Hauke Mehrtens
Jo-Philipp Wich
Leon M. George
Petr Štetiar
Hans Dedecker
Eneas U de Queiroz
Jeffery To
Kevin Darbyshire-Bryant
Martin Schiller
Matt Merhar
Jason A. Donenfeld
Christian Lamparter
Yousong Zhou
Lucian Cristian
Rosy Song
Stefan Lippers-Hollmann
Florian Eckert