Add `--enable-asan` and `--enable-ubsan` switches

`configure` now accepts `--enable-asan` and `--enable-ubsan` switches
which results in passing `-fsanitize=address`
and `-fsanitize=undefined`, respectively, to the compiler. Those
flags are enabled in GitHub workflows for ZTS and zloop. Errors
reported by both instrumentations are corrected, except for:

- Memory leak reporting is (temporarily) suppressed. The cost of
  fixing them is relatively high compared to the gains.

- Checksum computing functions in `module/zcommon/zfs_fletcher*`
  have UBSan errors suppressed. It is completely impractical
  to enforce 64-byte payload alignment there due to performance
  impact.

- There's no ASan heap poisoning in `module/zstd/lib/zstd.c`. A custom
  memory allocator is used there rendering that measure
  unfeasible.

- Memory leaks detection has to be suppressed for `cmd/zvol_id`.
  `zvol_id` is run by udev with the help of `ptrace(2)`. Tracing is
  incompatible with memory leaks detection.

Reviewed-by: Ahelenia Ziemiańska <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: szubersk <[email protected]>
Closes #12928 

1 files changed, 7 insertions, 2 deletions

diff --git a/module/icp/io/sha2_mod.c b/module/icp/io/sha2_mod.c
index a43c7c5b7..7ee16e137 100644
--- a/module/icp/io/sha2_mod.c
+++ b/module/icp/io/sha2_mod.c
@@ -710,8 +710,13 @@ sha2_mac_init_ctx(sha2_hmac_ctx_t *ctx, void *keyval, uint_t length_in_bytes)
 
 	(void) bzero(ipad, block_size);
 	(void) bzero(opad, block_size);
-	(void) bcopy(keyval, ipad, length_in_bytes);
-	(void) bcopy(keyval, opad, length_in_bytes);
+
+	if (keyval != NULL) {
+		(void) bcopy(keyval, ipad, length_in_bytes);
+		(void) bcopy(keyval, opad, length_in_bytes);
+	} else {
+		ASSERT0(length_in_bytes);
+	}
 
 	/* XOR key with ipad (0x36) and opad (0x5c) */
 	for (i = 0; i < blocks_per_int64; i ++) {