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authorEric Biggers <ebiggers@google.com>2018-01-11 23:30:08 -0500
committerTheodore Ts'o <tytso@mit.edu>2018-01-11 23:30:08 -0500
commit2cbadadcfdf0d8a538ce32ed12e18ef487773b07 (patch)
tree27e38f4642a9dd981e8cc7451b4f116cc678dea8 /fs/crypto
parent50c961de59ec841c1185c18457e6dab227f3bbf3 (diff)
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fscrypt: define fscrypt_fname_alloc_buffer() to be for presented names
Previously fscrypt_fname_alloc_buffer() was used to allocate buffers for both presented (decrypted or encoded) and encrypted filenames. That was confusing, because it had to allocate the worst-case size for either, e.g. including NUL-padding even when it was meaningless. But now that fscrypt_setup_filename() no longer calls it, it is only used in the ->get_link() and ->readdir() paths, which specifically want a buffer for presented filenames. Therefore, switch the behavior over to allocating the buffer for presented filenames only. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/crypto')
-rw-r--r--fs/crypto/fname.c29
1 files changed, 14 insertions, 15 deletions
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 65424b89a1d1..44ddd094b7c5 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -204,37 +204,36 @@ u32 fscrypt_fname_encrypted_size(const struct inode *inode, u32 ilen)
EXPORT_SYMBOL(fscrypt_fname_encrypted_size);
/**
- * fscrypt_fname_crypto_alloc_obuff() -
+ * fscrypt_fname_alloc_buffer - allocate a buffer for presented filenames
*
- * Allocates an output buffer that is sufficient for the crypto operation
- * specified by the context and the direction.
+ * Allocate a buffer that is large enough to hold any decrypted or encoded
+ * filename (null-terminated), for the given maximum encrypted filename length.
+ *
+ * Return: 0 on success, -errno on failure
*/
int fscrypt_fname_alloc_buffer(const struct inode *inode,
- u32 ilen, struct fscrypt_str *crypto_str)
+ u32 max_encrypted_len,
+ struct fscrypt_str *crypto_str)
{
- u32 olen = fscrypt_fname_encrypted_size(inode, ilen);
const u32 max_encoded_len =
max_t(u32, BASE64_CHARS(FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE),
1 + BASE64_CHARS(sizeof(struct fscrypt_digested_name)));
+ u32 max_presented_len;
- crypto_str->len = olen;
- olen = max(olen, max_encoded_len);
+ max_presented_len = max(max_encoded_len, max_encrypted_len);
- /*
- * Allocated buffer can hold one more character to null-terminate the
- * string
- */
- crypto_str->name = kmalloc(olen + 1, GFP_NOFS);
- if (!(crypto_str->name))
+ crypto_str->name = kmalloc(max_presented_len + 1, GFP_NOFS);
+ if (!crypto_str->name)
return -ENOMEM;
+ crypto_str->len = max_presented_len;
return 0;
}
EXPORT_SYMBOL(fscrypt_fname_alloc_buffer);
/**
- * fscrypt_fname_crypto_free_buffer() -
+ * fscrypt_fname_free_buffer - free the buffer for presented filenames
*
- * Frees the buffer allocated for crypto operation.
+ * Free the buffer allocated by fscrypt_fname_alloc_buffer().
*/
void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
{