diff options
author | Steven Noonan <steven@uplinklabs.net> | 2015-12-27 12:07:31 +0100 |
---|---|---|
committer | Thomas Petazzoni <thomas.petazzoni@free-electrons.com> | 2015-12-27 15:30:09 +0100 |
commit | d29c7196bf5e610123dcc697197d4013d5869f68 (patch) | |
tree | 208807555bb34233bab2817d968bc7e427a31daa /Config.in | |
parent | 9ac65b37bd34a4ba9a97156ace0fe91ce3670912 (diff) |
toolchain: granular choice for stack protector
Currently, we only support two levels of stach-smashing protection:
- entirely disabled,
- protect _all_ functions with -fstack-protector-all.
-fstack-protector-all tends to be far too aggressive and impacts
performance too much to be worth on a real product.
Add a choice that allows us to select between different levels of
stack-smashing protection:
- none
- basic (NEW)
- strong (NEW)
- all
The differences are documented in the GCC online documentation:
https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Optimize-Options.html
Signed-off-by: Steven Noonan <steven@uplinklabs.net>
[yann.morin.1998@free.fr:
- rebase
- add legacy handling
- SSP-strong depends on gcc >= 4.9
- slightly simple ifeq-block in package/Makefile.in
- keep the comment in the choice; add a comment shen strong is not
available
- drop the defaults (only keep the legacy)
- update commit log
]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
[Thomas:
- only show the choice if the toolchain has SSP support
- add details for the BR2_SSP_ALL option that it has a significant
performance impact.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Diffstat (limited to 'Config.in')
-rw-r--r-- | Config.in | 45 |
1 files changed, 41 insertions, 4 deletions
@@ -522,12 +522,13 @@ config BR2_GOOGLE_BREAKPAD_INCLUDE_FILES endif -config BR2_ENABLE_SSP +choice bool "build code with Stack Smashing Protection" + default BR2_SSP_ALL if BR2_ENABLE_SSP # legacy depends on BR2_TOOLCHAIN_HAS_SSP help - Enable stack smashing protection support using GCCs - -fstack-protector-all option. + Enable stack smashing protection support using GCC's + -fstack-protector option family. See http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt for details. @@ -536,7 +537,43 @@ config BR2_ENABLE_SSP support. This is always the case for glibc and eglibc toolchain, but is optional in uClibc toolchains. -comment "enabling Stack Smashing Protection requires support in the toolchain" +config BR2_SSP_NONE + bool "None" + help + Disable stack-smashing protection. + +config BR2_SSP_REGULAR + bool "-fstack-protector" + help + Emit extra code to check for buffer overflows, such as stack + smashing attacks. This is done by adding a guard variable to + functions with vulnerable objects. This includes functions + that call alloca, and functions with buffers larger than 8 + bytes. The guards are initialized when a function is entered + and then checked when the function exits. If a guard check + fails, an error message is printed and the program exits. + +config BR2_SSP_STRONG + bool "-fstack-protector-strong" + depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_9 + help + Like -fstack-protector but includes additional functions to be + protected - those that have local array definitions, or have + references to local frame addresses. + +comment "Stack Smashing Protection strong needs a toolchain w/ gcc >= 4.9" + depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_4_9 + +config BR2_SSP_ALL + bool "-fstack-protector-all" + help + Like -fstack-protector except that all functions are + protected. This option might have a significant performance + impact on the compiled binaries. + +endchoice + +comment "Stack Smashing Protection needs a toolchain w/ SSP" depends on !BR2_TOOLCHAIN_HAS_SSP choice |