Make SSP available for package builds #121
Open
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Partially addresses #22
Already tested by @areynold, @dismantl, and @hawkinswnaf.
Assigning to @technosopher to merge, since it will require a build server toolchain rebuild.
Instructions:
src-git areynold git://github.com/areynold/commotion-feed.git
to feeds.conf. (ssp_test does not need to be merged.)./setup.sh
cd openwrt
make menuconfig
4a. Select Commotion > Utilities > ssp_test, which includes SSP compile flags in its Makefile. (Note: I have occasionally had to deselect and reselect Advanced Configuration Options > Toolchain Options > Enable Stack-Smashing-Protection to make the test utility available.)
4b. Save and exit
cd /root
./smash
to find the address of the vulnerable function. Note that the address format is 0x followed by 8 digits. You only need the digits after "0x". If smash provides fewer than 8, pad the address with 0s as needed. Also note that you will need to reverse the address on little-endian machines. See examples below.printf "meat\x01\x12\x23\x34\x01\x12\x23\x34\x01\x12\x23\x34\x01\x12\x23\x34" | ./smash
. If the package was compiled with SSP, smash will abort with the message*** stack smashing detected ***: smash terminated Trace/breakpoint trap
. If not, it will execute the target function and print a message to the screen.Alternately, you can run
strings ./smash
and grep for "__stack_chk_fail", but that's not nearly as cool.Examples:
If smash returns 0x804849d, you will first need to pad the address (making it 0804849d).
On a big-endian device (such as ubiquiti routers) you would enter \x08\x04\x84\x9d.
On a little-endian device (such as x86) you would enter \x9d\x84\x04\x08.