From 50c961de59ec841c1185c18457e6dab227f3bbf3 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 11 Jan 2018 23:30:08 -0500 Subject: fscrypt: calculate NUL-padding length in one place only Currently, when encrypting a filename (either a real filename or a symlink target) we calculate the amount of NUL-padding twice: once before encryption and once during encryption in fname_encrypt(). It is needed before encryption to allocate the needed buffer size as well as calculate the size the symlink target will take up on-disk before creating the symlink inode. Calculating the size during encryption as well is redundant. Remove this redundancy by always calculating the exact size beforehand, and making fname_encrypt() just add as much NUL padding as is needed to fill the output buffer. Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o --- fs/crypto/hooks.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'fs/crypto/hooks.c') diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 8900e348ba6e..5bf38d94c5d2 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -161,7 +161,6 @@ int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, struct qstr iname = { .name = target, .len = len }; struct fscrypt_symlink_data *sd; unsigned int ciphertext_len; - struct fscrypt_str oname; err = fscrypt_require_key(inode); if (err) @@ -178,16 +177,12 @@ int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, ciphertext_len = disk_link->len - sizeof(*sd); sd->len = cpu_to_le16(ciphertext_len); - oname.name = sd->encrypted_path; - oname.len = ciphertext_len; - err = fname_encrypt(inode, &iname, &oname); + err = fname_encrypt(inode, &iname, sd->encrypted_path, ciphertext_len); if (err) { if (!disk_link->name) kfree(sd); return err; } - BUG_ON(oname.len != ciphertext_len); - /* * Null-terminating the ciphertext doesn't make sense, but we still * count the null terminator in the length, so we might as well -- cgit v1.2.3