From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F0BF8748D; Sat, 15 Feb 2025 12:41:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739623305; cv=none; b=UppqY2xAGKEcMb1NMre3WA9hBJil9cNGgADKgQNkG0UtJ5j9O+IQNetyv66k5MuzAxba2Ty8B4Qcvr8tB+mXI0ZuhlVplckqkAnoZAhfw6sxkeMBDhtM0ebaRrwxF6PKjX+u7qhsdAAVLmLBsreu6s0P4r+LGn/wSpysnaYMqvg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739623305; c=relaxed/simple; bh=hTRcluaXCD4NbfY/iwIWF7OPNbAWEt9IUSJEOK1Ncic=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=B7P5h9+YXQWydw4PBzfaMJn9COV0ycC8JDglpAo1DryTNsh/PoojAaAFz2fP1AI/TMEIW8NNzxttUMAUs4fKISvmAFkjZLlKxkNvwTrMxNXghXutSuTspEc0wHbKvgU00FK0iKY74wKLRQHtbJOTNRdL7/+FF8ZKQfizjva045c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=W2zAbfZp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="W2zAbfZp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D719FC4CEDF; Sat, 15 Feb 2025 12:41:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739623304; bh=hTRcluaXCD4NbfY/iwIWF7OPNbAWEt9IUSJEOK1Ncic=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=W2zAbfZp33zLD+9nsL1L2FNdMtoPRt7aKwwKsrq8GvD6wPKmpOM9oI7V/ijbggfpF eAXlGq1PLsSdplakKzKnypR5pvA8El2rFa5F20T5CWL0jdQRChyg6RgQOqrlI/MaqD PEXiaYGxr4ypFgpmhC36DzHbbMEoe8lvZV8Bc7VT0Z8EJfO0gmn2DfD4Dh56T9/TY4 47XE7gzhGHtJF00S2LuYkc/nKzzjQJaI8Ud6t6WMf3VkP8oIIUt7igUTIklWPm5xO0 oTQD+dbkaTQ5TEMKVPcXN5B+nsPdqHxc/YbGMZ/x8nI47mghtDcTxEl8iQOPV2TL7m RYC8QfwDBcacw== Message-ID: Subject: Re: [PATCH 1/2] prep for ceph_encode_encrypted_fname() fixes From: Jeff Layton To: Al Viro , Luis Henriques Cc: ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Ilya Dryomov Date: Sat, 15 Feb 2025 07:41:42 -0500 In-Reply-To: <20250215044714.GA3451131@ZenIV> References: <20250214024756.GY1977892@ZenIV> <20250214032820.GZ1977892@ZenIV> <87frkg7bqh.fsf@igalia.com> <20250215044616.GF1977892@ZenIV> <20250215044714.GA3451131@ZenIV> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 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ceph_encode_encrypted_dname() would be better off with plaintext name > already copied into buffer; we'll lift that into the callers on the > next step, which will allow to fix UAF on races with rename; for now > copy it in the very beginning of ceph_encode_encrypted_dname(). >=20 > That has a pleasant side benefit - we don't need to mess with tmp_buf > anymore (i.e. that's 256 bytes off the stack footprint). >=20 > Signed-off-by: Al Viro > --- > fs/ceph/crypto.c | 40 +++++++++++++++++----------------------- > 1 file changed, 17 insertions(+), 23 deletions(-) >=20 > diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c > index 3b3c4d8d401e..09346b91215a 100644 > --- a/fs/ceph/crypto.c > +++ b/fs/ceph/crypto.c > @@ -265,31 +265,28 @@ int ceph_encode_encrypted_dname(struct inode *paren= t, struct qstr *d_name, > { > struct ceph_client *cl =3D ceph_inode_to_client(parent); > struct inode *dir =3D parent; > - struct qstr iname; > + char *p =3D buf; > u32 len; > int name_len; > int elen; > int ret; > u8 *cryptbuf =3D NULL; > =20 > - iname.name =3D d_name->name; > - name_len =3D d_name->len; > + memcpy(buf, d_name->name, d_name->len); > + elen =3D d_name->len; > + > + name_len =3D elen; > =20 > /* Handle the special case of snapshot names that start with '_' */ > - if ((ceph_snap(dir) =3D=3D CEPH_SNAPDIR) && (name_len > 0) && > - (iname.name[0] =3D=3D '_')) { > - dir =3D parse_longname(parent, iname.name, &name_len); > + if (ceph_snap(dir) =3D=3D CEPH_SNAPDIR && *p =3D=3D '_') { > + dir =3D parse_longname(parent, p, &name_len); > if (IS_ERR(dir)) > return PTR_ERR(dir); > - iname.name++; /* skip initial '_' */ > + p++; /* skip initial '_' */ > } > - iname.len =3D name_len; > =20 > - if (!fscrypt_has_encryption_key(dir)) { > - memcpy(buf, d_name->name, d_name->len); > - elen =3D d_name->len; > + if (!fscrypt_has_encryption_key(dir)) > goto out; > - } > =20 > /* > * Convert cleartext d_name to ciphertext. If result is longer than > @@ -297,7 +294,7 @@ int ceph_encode_encrypted_dname(struct inode *parent,= struct qstr *d_name, > * > * See: fscrypt_setup_filename > */ > - if (!fscrypt_fname_encrypted_size(dir, iname.len, NAME_MAX, &len)) { > + if (!fscrypt_fname_encrypted_size(dir, name_len, NAME_MAX, &len)) { > elen =3D -ENAMETOOLONG; > goto out; > } > @@ -310,7 +307,9 @@ int ceph_encode_encrypted_dname(struct inode *parent,= struct qstr *d_name, > goto out; > } > =20 > - ret =3D fscrypt_fname_encrypt(dir, &iname, cryptbuf, len); > + ret =3D fscrypt_fname_encrypt(dir, > + &(struct qstr)QSTR_INIT(p, name_len), > + cryptbuf, len); > if (ret) { > elen =3D ret; > goto out; > @@ -331,18 +330,13 @@ int ceph_encode_encrypted_dname(struct inode *paren= t, struct qstr *d_name, > } > =20 > /* base64 encode the encrypted name */ > - elen =3D ceph_base64_encode(cryptbuf, len, buf); > - doutc(cl, "base64-encoded ciphertext name =3D %.*s\n", elen, buf); > + elen =3D ceph_base64_encode(cryptbuf, len, p); > + doutc(cl, "base64-encoded ciphertext name =3D %.*s\n", elen, p); > =20 > /* To understand the 240 limit, see CEPH_NOHASH_NAME_MAX comments */ > WARN_ON(elen > 240); > - if ((elen > 0) && (dir !=3D parent)) { > - char tmp_buf[NAME_MAX]; > - > - elen =3D snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld", > - elen, buf, dir->i_ino); > - memcpy(buf, tmp_buf, elen); > - } > + if (dir !=3D parent) // leading _ is already there; append _ > + elen +=3D 1 + sprintf(p + elen, "_%ld", dir->i_ino); > =20 > out: > kfree(cryptbuf); Reviewed-by: Jeff Layton