From 888d33b208bd6929808abdc0728e3e5f744b60dc Mon Sep 17 00:00:00 2001 From: Sam Edwards Date: Fri, 29 May 2026 20:06:45 -0700 Subject: [PATCH] ceph: pass fscrypt `tname` buffers directly ceph_fname_to_usr() needs a temporary buffer for some operations (currently only base64-decoding ciphertext) and it is convenient to allow the caller to specify this buffer to avoid a heap allocation, so it has a (nullable) `tname` argument. Until now, this argument was a `struct fscrypt_str`; however, this is unnecessary for two reasons: 1. `tname->len` isn't used anywhere: ceph_fname_to_usr() assumes a buffer large enough to hold the ciphertext, and parse_reply_info_readdir() -- the only caller to use tname -- doesn't set it. 2. While the `tname` parameter is documented "may be NULL," parse_reply_info_readdir() always passes it but with `tname->name` sometimes NULL in violation of the contract, indicating that the unnecessary container creates actual confusion. Therefore, change the type to `unsigned char *` and pass the buffer directly. Signed-off-by: Sam Edwards Reviewed-by: Alex Markuze Signed-off-by: Ilya Dryomov --- fs/ceph/crypto.c | 9 ++++----- fs/ceph/crypto.h | 4 ++-- fs/ceph/mds_client.c | 6 +++--- 3 files changed, 9 insertions(+), 10 deletions(-) diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c index 64d240759277..7493a3acd7d0 100644 --- a/fs/ceph/crypto.c +++ b/fs/ceph/crypto.c @@ -300,7 +300,7 @@ int ceph_encode_encrypted_dname(struct inode *parent, char *buf, int elen) * * Returns 0 on success or negative error code on error. */ -int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, +int ceph_fname_to_usr(const struct ceph_fname *fname, unsigned char *tname, struct fscrypt_str *oname, bool *is_nokey) { struct inode *dir = fname->dir; @@ -357,16 +357,15 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, ret = fscrypt_fname_alloc_buffer(NAME_MAX, &_tname); if (ret) goto out_inode; - tname = &_tname; + tname = _tname.name; } - declen = base64_decode(name, name_len, - tname->name, false, BASE64_IMAP); + declen = base64_decode(name, name_len, tname, false, BASE64_IMAP); if (declen <= 0) { ret = -EIO; goto out; } - iname.name = tname->name; + iname.name = tname; iname.len = declen; } else { iname.name = fname->ctext; diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h index b748e2060bc9..79cb563fd887 100644 --- a/fs/ceph/crypto.h +++ b/fs/ceph/crypto.h @@ -115,7 +115,7 @@ static inline void ceph_fname_free_buffer(struct inode *parent, fscrypt_fname_free_buffer(fname); } -int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, +int ceph_fname_to_usr(const struct ceph_fname *fname, unsigned char *tname, struct fscrypt_str *oname, bool *is_nokey); int ceph_fscrypt_prepare_readdir(struct inode *dir); @@ -204,7 +204,7 @@ static inline void ceph_fname_free_buffer(struct inode *parent, } static inline int ceph_fname_to_usr(const struct ceph_fname *fname, - struct fscrypt_str *tname, + unsigned char *tname, struct fscrypt_str *oname, bool *is_nokey) { oname->name = fname->name; diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 3c692ad02c85..80c72f295bcb 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -491,11 +491,11 @@ static int parse_reply_info_readdir(void **p, void *end, struct inode *inode = d_inode(req->r_dentry); struct ceph_inode_info *ci = ceph_inode(inode); struct ceph_mds_reply_dir_entry *rde = info->dir_entries + i; - struct fscrypt_str tname = FSTR_INIT(NULL, 0); struct fscrypt_str oname = FSTR_INIT(NULL, 0); struct ceph_fname fname; u32 altname_len, _name_len; u8 *altname, *_name; + u8 *tname = NULL; /* dentry */ ceph_decode_32_safe(p, end, _name_len, bad); @@ -543,7 +543,7 @@ static int parse_reply_info_readdir(void **p, void *end, * always be shorter, which is 3/4 of origin * string. */ - tname.name = _name; + tname = _name; /* * Set oname to _name too, and this will be @@ -560,7 +560,7 @@ static int parse_reply_info_readdir(void **p, void *end, oname.len = altname_len; } rde->is_nokey = false; - err = ceph_fname_to_usr(&fname, &tname, &oname, &rde->is_nokey); + err = ceph_fname_to_usr(&fname, tname, &oname, &rde->is_nokey); if (err) { pr_err_client(cl, "unable to decode %.*s, got %d\n", _name_len, _name, err);