On 8/14/24 04:10, Hongbo Li wrote:
On 2024/8/13 21:16, Mae Kasza wrote:
On 8/12/24 04:50, Hongbo Li wrote:
On 2024/8/12 9:41, Kent Overstreet wrote:
On Sun, Aug 11, 2024 at 11:40:38PM GMT, Mae Kasza wrote:
From: mae <[email protected]>
The set-passphrase command failed to derive the key for disks
initially
formatted with --encrypted and --no_passphrase.
This happened because bch_sb_crypt_init only configures the KDF
params
if a passphrase is specified.
This commit makes the command initialize the KDF with the same
parameters
as bch_sb_crypt_init if the key wasn't encrypted before.
Signed-off-by: Mae Kasza <[email protected]>
This looks good to me, but I'm in the middle of a 20 hour drive and
not
feeling super confident to review crypto stuff tonight, so maybe
someone
else can go over it too before I pull it in..
---
c_src/cmd_key.c | 9 +++++++--
c_src/crypto.c | 13 ++++++++-----
c_src/crypto.h | 1 +
3 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/c_src/cmd_key.c b/c_src/cmd_key.c
index adb0ac8d..2da83758 100644
--- a/c_src/cmd_key.c
+++ b/c_src/cmd_key.c
@@ -104,7 +104,8 @@ int cmd_set_passphrase(int argc, char *argv[])
if (IS_ERR(c))
die("Error opening %s: %s", argv[1],
bch2_err_str(PTR_ERR(c)));
- struct bch_sb_field_crypt *crypt =
bch2_sb_field_get(c->disk_sb.sb, crypt);
+ struct bch_sb *sb = c->disk_sb.sb;
+ struct bch_sb_field_crypt *crypt = bch2_sb_field_get(sb, crypt);
if (!crypt)
die("Filesystem does not have encryption enabled");
@@ -116,9 +117,13 @@ int cmd_set_passphrase(int argc, char *argv[])
die("Error getting current key");
char *new_passphrase = read_passphrase_twice("Enter new
passphrase: ");
+ if (!bch2_key_is_encrypted(&crypt->key)) {
+ bch_crypt_default_kdf_init(crypt);
It works, but using bch_sb_crypt_init to reinitialize crypt may be
better. In bch_sb_crypt_init, it has initialized the crypt and also
cleaned new_passphrase.
Thanks
Hongbo
bch_sb_crypt_init also reinitializes the crypt->key, so I can't just
reuse it here.
Yeah, it will change crypt->key. It seems the main point is not clean
the password.
Do we need keep the crypt->key even the password is changed? Or does
the crypt->key like a random seed and need to be kept in the whole
lifecycle? Sorry I am a bit confused about this.
Thanks,
Hongbo
crypt->key does need to stay constant for the entire lifetime of a
partition, since that's what's actually used to encrypt the data on the
partition. The passphrase is just used to encrypt the crypt->key
Thanks,
Mae
I could extract it into a bch_crypt_update_passphrase function.
Originally I wanted to avoid doing that to limit the scope of this
patchset, but I'll give it a shot
Thanks for the review!
Mae
+ }
+
struct bch_key passphrase_key = derive_passphrase(crypt,
new_passphrase);
- if (bch2_chacha_encrypt_key(&passphrase_key,
__bch2_sb_key_nonce(c->disk_sb.sb),
+ if (bch2_chacha_encrypt_key(&passphrase_key,
__bch2_sb_key_nonce(sb),
&new_key, sizeof(new_key)))
die("error encrypting key");
crypt->key = new_key;
diff --git a/c_src/crypto.c b/c_src/crypto.c
index 32671bd8..30ad92d4 100644
--- a/c_src/crypto.c
+++ b/c_src/crypto.c
@@ -180,11 +180,7 @@ void bch_sb_crypt_init(struct bch_sb *sb,
get_random_bytes(&crypt->key.key, sizeof(crypt->key.key));
if (passphrase) {
-
- SET_BCH_CRYPT_KDF_TYPE(crypt, BCH_KDF_SCRYPT);
- SET_BCH_KDF_SCRYPT_N(crypt, ilog2(16384));
- SET_BCH_KDF_SCRYPT_R(crypt, ilog2(8));
- SET_BCH_KDF_SCRYPT_P(crypt, ilog2(16));
+ bch_crypt_default_kdf_init(crypt);
struct bch_key passphrase_key =
derive_passphrase(crypt, passphrase);
@@ -199,3 +195,10 @@ void bch_sb_crypt_init(struct bch_sb *sb,
memzero_explicit(&passphrase_key, sizeof(passphrase_key));
}
}
+
+void bch_crypt_default_kdf_init(struct bch_sb_field_crypt *crypt) {
+ SET_BCH_CRYPT_KDF_TYPE(crypt, BCH_KDF_SCRYPT);
+ SET_BCH_KDF_SCRYPT_N(crypt, ilog2(16384));
+ SET_BCH_KDF_SCRYPT_R(crypt, ilog2(8));
+ SET_BCH_KDF_SCRYPT_P(crypt, ilog2(16));
+}
diff --git a/c_src/crypto.h b/c_src/crypto.h
index baea6d86..846a8931 100644
--- a/c_src/crypto.h
+++ b/c_src/crypto.h
@@ -18,5 +18,6 @@ void bch2_passphrase_check(struct bch_sb *,
const char *,
void bch2_add_key(struct bch_sb *, const char *, const char *,
const char *);
void bch_sb_crypt_init(struct bch_sb *sb, struct
bch_sb_field_crypt *,
const char *);
+void bch_crypt_default_kdf_init(struct bch_sb_field_crypt *);
#endif /* _CRYPTO_H */
--
2.45.2
