fscrypt: make fscrypt_set_test_dummy_encryption() take a 'const char *'

fscrypt_set_test_dummy_encryption() requires that the optional argument
to the test_dummy_encryption mount option be specified as a substring_t.
That doesn't work well with filesystems that use the new mount API,
since the new way of parsing mount options doesn't use substring_t.

Make it take the argument as a 'const char *' instead.

Instead of moving the match_strdup() into the callers in ext4 and f2fs,
make them just use arg->from directly.  Since the pattern is
"test_dummy_encryption=%s", the argument will be null-terminated.

Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-14-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 97cf07543651f54c603451cfa747d61982acb000..4441d9944b9effe67d2b1c58e2ebf8b85a699b3a 100644 (file)
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -697,8 +697,7 @@ EXPORT_SYMBOL_GPL(fscrypt_set_context);
 /**
  * fscrypt_set_test_dummy_encryption() - handle '-o test_dummy_encryption'
  * @sb: the filesystem on which test_dummy_encryption is being specified
- * @arg: the argument to the test_dummy_encryption option.
- *      If no argument was specified, then @arg->from == NULL.
+ * @arg: the argument to the test_dummy_encryption option.  May be NULL.
  * @dummy_policy: the filesystem's current dummy policy (input/output, see
  *               below)
  *
@@ -712,29 +711,23 @@ EXPORT_SYMBOL_GPL(fscrypt_set_context);
  *         -EEXIST if a different dummy policy is already set;
  *         or another -errno value.
  */
-int fscrypt_set_test_dummy_encryption(struct super_block *sb,
-                                     const substring_t *arg,
+int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
                                      struct fscrypt_dummy_policy *dummy_policy)
 {
-       const char *argstr = "v2";
-       const char *argstr_to_free = NULL;
        struct fscrypt_key_specifier key_spec = { 0 };
        int version;
        union fscrypt_policy *policy = NULL;
        int err;
 
-       if (arg->from) {
-               argstr = argstr_to_free = match_strdup(arg);
-               if (!argstr)
-                       return -ENOMEM;
-       }
+       if (!arg)
+               arg = "v2";
 
-       if (!strcmp(argstr, "v1")) {
+       if (!strcmp(arg, "v1")) {
                version = FSCRYPT_POLICY_V1;
                key_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
                memset(key_spec.u.descriptor, 0x42,
                       FSCRYPT_KEY_DESCRIPTOR_SIZE);
-       } else if (!strcmp(argstr, "v2")) {
+       } else if (!strcmp(arg, "v2")) {
                version = FSCRYPT_POLICY_V2;
                key_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
                /* key_spec.u.identifier gets filled in when adding the key */
@@ -785,7 +778,6 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb,
        err = 0;
 out:
        kfree(policy);
-       kfree(argstr_to_free);
        return err;
 }
 EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption);

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index aa6f64badf58a6315b9c011fbdcd9a1336c91d31..8b273628348131002763471b2251a7e5d8799a93 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1892,7 +1892,7 @@ static int ext4_set_test_dummy_encryption(struct super_block *sb,
                         "Can't set test_dummy_encryption on remount");
                return -1;
        }
-       err = fscrypt_set_test_dummy_encryption(sb, arg,
+       err = fscrypt_set_test_dummy_encryption(sb, arg->from,
                                                &sbi->s_dummy_enc_policy);
        if (err) {
                if (err == -EEXIST)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index f05ee33f5f26bfb11d0526b41789d67ee94b84e0..bef2be3fa3d0680398a264a06d891bd717fed4f5 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -438,7 +438,7 @@ static int f2fs_set_test_dummy_encryption(struct super_block *sb,
                return -EINVAL;
        }
        err = fscrypt_set_test_dummy_encryption(
-               sb, arg, &F2FS_OPTION(sbi).dummy_enc_policy);
+               sb, arg->from, &F2FS_OPTION(sbi).dummy_enc_policy);
        if (err) {
                if (err == -EEXIST)
                        f2fs_warn(sbi,

diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index b3b0c5675c6b1909ed35f8fd968d507e324e527f..fc67c4cbaa9681e376747ff95f4ca7f027a30ea0 100644 (file)
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -15,7 +15,6 @@
 
 #include <linux/fs.h>
 #include <linux/mm.h>
-#include <linux/parser.h>
 #include <linux/slab.h>
 #include <uapi/linux/fscrypt.h>
 
@@ -153,9 +152,7 @@ struct fscrypt_dummy_policy {
        const union fscrypt_policy *policy;
 };
 
-int fscrypt_set_test_dummy_encryption(
-                               struct super_block *sb,
-                               const substring_t *arg,
+int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
                                struct fscrypt_dummy_policy *dummy_policy);
 void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
                                        struct super_block *sb);