diff options
| author | Nicolai Stange <nstange@suse.de> | 2021-11-30 17:10:09 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2021-12-11 08:48:06 +0300 |
| commit | 710ce4b88f9a93a6b2c2267e8f27ba65af3cb6ac (patch) | |
| tree | eb7681a897a48f8a653422d7acf37a02ba9d397b /crypto | |
| parent | b454fb702515276041b701a4eda468b6cd6b384d (diff) | |
| download | linux-710ce4b88f9a93a6b2c2267e8f27ba65af3cb6ac.tar.xz | |
crypto: jitter - quit sample collection loop upon RCT failure
The jitterentropy collection loop in jent_gen_entropy() can in principle
run indefinitely without making any progress if it only receives stuck
measurements as determined by jent_stuck(). After 31 consecutive stuck
samples, the Repetition Count Test (RCT) would fail anyway and the
jitterentropy RNG instances moved into ->health_failure == 1 state.
jent_gen_entropy()'s caller, jent_read_entropy() would then check for
this ->health_failure condition and return an error if found set. It
follows that there's absolutely no point in continuing the collection loop
in jent_gen_entropy() once the RCT has failed.
Make the jitterentropy collection loop more robust by terminating it upon
jent_health_failure() so that it won't continue to run indefinitely without
making any progress.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/jitterentropy.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/crypto/jitterentropy.c b/crypto/jitterentropy.c index 24e087c3f526..8f5283f28ed3 100644 --- a/crypto/jitterentropy.c +++ b/crypto/jitterentropy.c @@ -547,7 +547,7 @@ static void jent_gen_entropy(struct rand_data *ec) /* priming of the ->prev_time value */ jent_measure_jitter(ec); - while (1) { + while (!jent_health_failure(ec)) { /* If a stuck measurement is received, repeat measurement */ if (jent_measure_jitter(ec)) continue; |