bcachefs: Fix bch2_alloc_ciphers()

Don't put error pointers in bch_fs, that's gross.

This fixes (?) the check in bch2_checksum_type_valid() - depending on
our error paths, or depending on what our error paths are doing it at
least makes the code saner.

Reported-by: syzbot+2e3cb81b5d1fe18a374b@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/checksum.c b/fs/bcachefs/checksum.c
index 85198f391e9c8fbb18e44cb53c1c36b5dbf60391..fc9a2b2a916f0fca60852f2e2c2a97b7a01c7a3c 100644 (file)
--- a/fs/bcachefs/checksum.c
+++ b/fs/bcachefs/checksum.c
@@ -648,26 +648,26 @@ err:
 
 static int bch2_alloc_ciphers(struct bch_fs *c)
 {
-       int ret;
-
-       if (!c->chacha20)
-               c->chacha20 = crypto_alloc_sync_skcipher("chacha20", 0, 0);
-       ret = PTR_ERR_OR_ZERO(c->chacha20);
+       if (c->chacha20)
+               return 0;
 
+       struct crypto_sync_skcipher *chacha20 = crypto_alloc_sync_skcipher("chacha20", 0, 0);
+       int ret = PTR_ERR_OR_ZERO(chacha20);
        if (ret) {
                bch_err(c, "error requesting chacha20 module: %s", bch2_err_str(ret));
                return ret;
        }
 
-       if (!c->poly1305)
-               c->poly1305 = crypto_alloc_shash("poly1305", 0, 0);
-       ret = PTR_ERR_OR_ZERO(c->poly1305);
-
+       struct crypto_shash *poly1305 = crypto_alloc_shash("poly1305", 0, 0);
+       ret = PTR_ERR_OR_ZERO(poly1305);
        if (ret) {
                bch_err(c, "error requesting poly1305 module: %s", bch2_err_str(ret));
+               crypto_free_sync_skcipher(chacha20);
                return ret;
        }
 
+       c->chacha20     = chacha20;
+       c->poly1305     = poly1305;
        return 0;
 }
 
@@ -762,11 +762,11 @@ err:
 
 void bch2_fs_encryption_exit(struct bch_fs *c)
 {
-       if (!IS_ERR_OR_NULL(c->poly1305))
+       if (c->poly1305)
                crypto_free_shash(c->poly1305);
-       if (!IS_ERR_OR_NULL(c->chacha20))
+       if (c->chacha20)
                crypto_free_sync_skcipher(c->chacha20);
-       if (!IS_ERR_OR_NULL(c->sha256))
+       if (c->sha256)
                crypto_free_shash(c->sha256);
 }
 
@@ -779,6 +779,7 @@ int bch2_fs_encryption_init(struct bch_fs *c)
        c->sha256 = crypto_alloc_shash("sha256", 0, 0);
        ret = PTR_ERR_OR_ZERO(c->sha256);
        if (ret) {
+               c->sha256 = NULL;
                bch_err(c, "error requesting sha256 module: %s", bch2_err_str(ret));
                goto out;
        }