Eric Biggers <ebiggers@xxxxxxxxxx> writes: > On Fri, Mar 15, 2019 at 03:24:35PM +1100, Daniel Axtens wrote: ... >> >> This leads to corruption of the IV, which leads to subsequent blocks >> >> being corrupted. >> >> >> >> This can be detected with libkcapi test suite, which is available at >> >> https://github.com/smuellerDD/libkcapi >> > >> > Is this also detected by the kernel's crypto self-tests, and if not why not? >> > What about with the new option CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y? >> >> It seems the self-tests do not catch it. To catch it, there has to be a >> test where the blkcipher_walk creates a walk.nbytes such that >> [(the number of AES blocks) mod 8] is either 2 or 3. This happens with >> AF_ALG pretty frequently, but when I booted with self-tests it only hit >> 1, 4, 5, 6 and 7 - it missed 0, 2 and 3. >> >> I don't have the EXTRA_TESTS option - I'm testing with 5.0-rc6. Is it in >> -next? > > The improvements I recently made to the self-tests are intended to catch exactly > this sort of bug. They were just merged for v5.1, so try the latest mainline. > This almost certainly would be caught by EXTRA_TESTS (and if not I'd want to > know), but it may be caught by the regular self-tests now too. Enabling the crypto tests (CONFIG_CRYPTO_MANAGER_DISABLE_TESTS=n) actually hides the bug for me. By which I mean I can't trigger the bug via kcapi-enc-tests.sh, because the VMX code is never called. ie: # zgrep -e CRYPTO_MANAGER -e VMX /proc/config.gz CONFIG_CRYPTO_MANAGER=y CONFIG_CRYPTO_MANAGER2=y # CONFIG_CRYPTO_MANAGER_DISABLE_TESTS is not set # CONFIG_CRYPTO_MANAGER_EXTRA_TESTS is not set CONFIG_CRYPTO_DEV_VMX=y CONFIG_CRYPTO_DEV_VMX_ENCRYPT=y # echo "p:p8_aes_ctr_crypt p8_aes_ctr_crypt" > /sys/kernel/debug/tracing/kprobe_events # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable # ./kcapi-enc-test.sh ... Number of failures: 0 # grep -c p8_aes_ctr_crypt /sys/kernel/debug/tracing/trace 0 I don't understand how the crypto core chooses which crypto_alg to use, but I didn't expect enabling the tests to change it? cheers
