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d447cd596f
Both Android's libc and glibc support _FORTIFY_SOURCE, a compiler
and libc feature which inserts automatic bounds checking into
common C functions such as memcpy() and strcpy(). If a buffer
overflow occurs when calling a hardened libc function, the
automatic bounds checking will safely shutdown the program and
prevent memory corruption.
Android is experimenting with _FORTIFY_SOURCE=3, a new fortify
level which enhances memcpy() to prevent overflowing an element
of a struct. Under the enhancements, code such as
struct foo {
char empty[0];
char one[1];
char a[10];
char b[10];
};
int main() {
foo myfoo;
int n = atoi("11");
memcpy(myfoo.a, "01234567890123456789", n);
return 0;
}
will cleanly crash when the memcpy() call is made.
Fixup hostap code to support the new level. Specifically:
* Fixup sha1_transform so it works with the enhanced bounds checking.
The old memcpy() code was attempting to write to context.h0, but that
structure element is too small and the write was extending (by design)
into h1, h2, h3, and h4. Use explicit assignments instead of
overflowing the struct element.
* Modify most of the structures in ieee802_11_defs.h to use ISO C99
flexible array members (https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html)
instead of a zero length array. Zero length arrays have zero length,
and any attempt to call memcpy() on such elements will always overflow.
Flexible array members have no such limitation. The only element not
adjusted is probe_req, since doing so will generate a compile time error,
and it's not obvious to me how to fix it.
Signed-off-by: Nick Kralevich <nnk@google.com>
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| doc | ||
| eap_example | ||
| hostapd | ||
| hs20 | ||
| mac80211_hwsim | ||
| patches | ||
| radius_example | ||
| src | ||
| tests | ||
| wlantest | ||
| wpa_supplicant | ||
| wpadebug | ||
| wpaspy | ||
| .gitignore | ||
| Android.mk | ||
| build_release | ||
| CONTRIBUTIONS | ||
| COPYING | ||
| README | ||
wpa_supplicant and hostapd -------------------------- Copyright (c) 2002-2015, Jouni Malinen <j@w1.fi> and contributors All Rights Reserved. These programs are licensed under the BSD license (the one with advertisement clause removed). If you are submitting changes to the project, please see CONTRIBUTIONS file for more instructions. This package may include either wpa_supplicant, hostapd, or both. See README file respective subdirectories (wpa_supplicant/README or hostapd/README) for more details. Source code files were moved around in v0.6.x releases and compared to earlier releases, the programs are now built by first going to a subdirectory (wpa_supplicant or hostapd) and creating build configuration (.config) and running 'make' there (for Linux/BSD/cygwin builds). License ------- This software may be distributed, used, and modified under the terms of BSD license: Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name(s) of the above-listed copyright holder(s) nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.