crypto/shachain: detect if we're inserting a bogus hash.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/ccan/crypto/shachain/shachain.c b/ccan/crypto/shachain/shachain.c
index c66196f71d881ce5e19b9bc088d66b9d2fc8b03b..a14d95b8cd4d4c665dca18ab88313f90677e314d 100644 (file)
--- a/ccan/crypto/shachain/shachain.c
+++ b/ccan/crypto/shachain/shachain.c
@@ -49,7 +49,7 @@ void shachain_init(struct shachain *shachain)
        shachain->num_valid = 0;
 }
 
-void shachain_add_hash(struct shachain *chain,
+bool shachain_add_hash(struct shachain *chain,
                       shachain_index_t index, const struct sha256 *hash)
 {
        int i;
@@ -57,8 +57,16 @@ void shachain_add_hash(struct shachain *chain,
        for (i = 0; i < chain->num_valid; i++) {
                /* If we could derive this value, we don't need it,
                 * not any others (since they're in order). */
-               if (can_derive(index, chain->known[i].index))
+               if (can_derive(index, chain->known[i].index)) {
+                       struct sha256 expect;
+
+                       /* Make sure the others derive as expected! */
+                       derive(index, chain->known[i].index, hash, &expect);
+                       if (memcmp(&expect, &chain->known[i].hash,
+                                  sizeof(expect)) != 0)
+                               return false;
                        break;
+               }
        }
 
        /* This can happen if you skip indices! */
@@ -66,6 +74,7 @@ void shachain_add_hash(struct shachain *chain,
        chain->known[i].index = index;
        chain->known[i].hash = *hash;
        chain->num_valid = i+1;
+       return true;
 }
 
 bool shachain_get_hash(const struct shachain *chain,

diff --git a/ccan/crypto/shachain/shachain.h b/ccan/crypto/shachain/shachain.h
index b0f947e90c112ba2c1038978f15984fbea872394..39d6f3c4c6897b73112fa6ba02646c3dfb5e5115 100644 (file)
--- a/ccan/crypto/shachain/shachain.h
+++ b/ccan/crypto/shachain/shachain.h
@@ -24,7 +24,7 @@ struct shachain {
 
 void shachain_init(struct shachain *shachain);
 
-void shachain_add_hash(struct shachain *shachain,
+bool shachain_add_hash(struct shachain *shachain,
                       shachain_index_t index, const struct sha256 *hash);
 
 bool shachain_get_hash(const struct shachain *shachain,

diff --git a/ccan/crypto/shachain/test/run-8bit.c b/ccan/crypto/shachain/test/run-8bit.c
index 10520bc354d8f4ce2aa99e424bf0d218b71098af..64b1c7f44b9f7fa32bcf651f48945ce40c379a91 100644 (file)
--- a/ccan/crypto/shachain/test/run-8bit.c
+++ b/ccan/crypto/shachain/test/run-8bit.c
@@ -17,7 +17,7 @@ int main(void)
        size_t i, j;
 
        /* This is how many tests you plan to run */
-       plan_tests(NUM_TESTS + NUM_TESTS * (NUM_TESTS + 1) + NUM_TESTS);
+       plan_tests(NUM_TESTS * 3 + NUM_TESTS * (NUM_TESTS + 1));
 
        memset(&seed, 0, sizeof(seed));
        /* Generate a whole heap. */
@@ -34,7 +34,7 @@ int main(void)
        for (i = 0; i < NUM_TESTS; i++) {
                struct sha256 hash;
 
-               shachain_add_hash(&chain, i, &expect[i]);
+               ok1(shachain_add_hash(&chain, i, &expect[i]));
                for (j = 0; j <= i; j++) {
                        ok1(shachain_get_hash(&chain, j, &hash));
                        ok1(memcmp(&hash, &expect[j], sizeof(hash)) == 0);

diff --git a/ccan/crypto/shachain/test/run-badhash.c b/ccan/crypto/shachain/test/run-badhash.c
new file mode 100644 (file)
index 0000000..bc97851
--- /dev/null
+++ b/ccan/crypto/shachain/test/run-badhash.c
@@ -0,0 +1,38 @@
+#include <ccan/crypto/shachain/shachain.h>
+/* Include the C files directly. */
+#include <ccan/crypto/shachain/shachain.c>
+#include <ccan/tap/tap.h>
+
+#define NUM_TESTS 1000
+
+int main(void)
+{
+       struct sha256 seed;
+       struct shachain chain;
+       size_t i;
+
+       plan_tests(NUM_TESTS);
+
+       memset(&seed, 0xFF, sizeof(seed));
+       shachain_init(&chain);
+
+       for (i = 0; i < NUM_TESTS; i++) {
+               struct sha256 expect;
+               unsigned int num_known = chain.num_valid;
+
+               shachain_from_seed(&seed, i, &expect);
+               /* Screw it up. */
+               expect.u.u8[0]++;
+
+               /* Either it should fail, or it couldn't derive any others. */
+               if (shachain_add_hash(&chain, i, &expect)) {
+                       ok1(chain.num_valid == num_known + 1);
+                       /* Fix it up in-place */
+                       chain.known[num_known].hash.u.u8[0]--;
+               } else {
+                       expect.u.u8[0]--;
+                       ok1(shachain_add_hash(&chain, i, &expect));
+               }
+       }
+       return exit_status();
+}

diff --git a/ccan/crypto/shachain/test/run.c b/ccan/crypto/shachain/test/run.c
index 39391685606109e8a51e1c5ec7836859d871dac4..16fc5e871cf3149df0f62c50880165fb18890aea 100644 (file)
--- a/ccan/crypto/shachain/test/run.c
+++ b/ccan/crypto/shachain/test/run.c
@@ -13,7 +13,7 @@ int main(void)
        size_t i, j;
 
        /* This is how many tests you plan to run */
-       plan_tests(NUM_TESTS + NUM_TESTS * (NUM_TESTS + 1) + NUM_TESTS);
+       plan_tests(NUM_TESTS * 3 + NUM_TESTS * (NUM_TESTS + 1));
 
        memset(&seed, 0, sizeof(seed));
        /* Generate a whole heap. */
@@ -30,7 +30,7 @@ int main(void)
        for (i = 0; i < NUM_TESTS; i++) {
                struct sha256 hash;
 
-               shachain_add_hash(&chain, i, &expect[i]);
+               ok1(shachain_add_hash(&chain, i, &expect[i]));
                for (j = 0; j <= i; j++) {
                        ok1(shachain_get_hash(&chain, j, &hash));
                        ok1(memcmp(&hash, &expect[j], sizeof(hash)) == 0);