From patchwork Tue Aug 6 23:09:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 13755418 X-Patchwork-Delegate: bpf@iogearbox.net 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 99B5618D644; Tue, 6 Aug 2024 23:09:18 +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=1722985758; cv=none; b=lRzKA2IaTtxRzKvzArF9xkD+JMCvUvJjgM2kkSVi/O9txf+0CWCCBHTfcS5yV/L0iqCE6g2JfMhYNYB0JurToduEmC4YX5wdc7Sc9171bY9QW1A2YMjjsKwlu3DSWp/edf4zfxVSZu6P881fZEJD4ec0KdhOjCFGXSXn5RRXV6A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722985758; c=relaxed/simple; bh=jwYZyFVonBCcgA3xtSOFJjNT72e2XtxQf3pPEQ4zm6Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OPvGDtIY1Rmlf2SeTUjlIz/317wBdYP2VTq4VMGSY4sRI+mZsRjA9ApzZo+ANiMV+Rzo0evdHPPxoCEjshGGxeUZpVjRIKrNxJZgRl8rOL1R+MvbWLNx1QN+QoLqK6eV16X0Q0CRQHSf79OpsrTg4KpAJ3thuCz6hAfggrpQX1w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D/122gSf; 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="D/122gSf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88D5FC32786; Tue, 6 Aug 2024 23:09:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722985758; bh=jwYZyFVonBCcgA3xtSOFJjNT72e2XtxQf3pPEQ4zm6Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D/122gSfrsK8hCyPm8DiZLtD8Kp6wU196iVCdFZvq0HUoCrLAS8LwHLG6J60wMRgA cZYXhBdZOpK/Xt5Ygy0/5N/8ei0GUx7GyRoQWV4Qrn1MdSeuqR/uis5Kw9Dn/WjEae nHERAoDiShKoG5+caJRWKgXRalV5yDpdX0WiRmNrPBHeU/ZVN+P67jLRaWbkPuY3hv CRqBqrBprRDRFU7pFvsfTejxjN2xZpySsrtakyINj1DzdOhb6itfjDIugpBY6kyi2a JKKCbCmJmYn9LlzDc/Bl2bRc7WQVpFdlh9lPskCgB6E3w7+aEd0t2sb+6KZlTeHh6u Jn81JbybRI5MA== From: Song Liu To: bpf@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: kernel-team@meta.com, andrii@kernel.org, eddyz87@gmail.com, ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, kpsingh@kernel.org, liamwisehart@meta.com, lltang@meta.com, shankaran@meta.com, Song Liu Subject: [PATCH v4 bpf-next 1/3] bpf: Move bpf_get_file_xattr to fs/bpf_fs_kfuncs.c Date: Tue, 6 Aug 2024 16:09:02 -0700 Message-ID: <20240806230904.71194-2-song@kernel.org> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20240806230904.71194-1-song@kernel.org> References: <20240806230904.71194-1-song@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net We are putting all fs kfuncs in fs/bpf_fs_kfuncs.c. Move existing bpf_get_file_xattr to it. Signed-off-by: Song Liu --- fs/bpf_fs_kfuncs.c | 38 ++++++++++++++++++++++ kernel/trace/bpf_trace.c | 68 ---------------------------------------- 2 files changed, 38 insertions(+), 68 deletions(-) diff --git a/fs/bpf_fs_kfuncs.c b/fs/bpf_fs_kfuncs.c index 1e6e08667758..b13d00f7ad2b 100644 --- a/fs/bpf_fs_kfuncs.c +++ b/fs/bpf_fs_kfuncs.c @@ -8,6 +8,7 @@ #include #include #include +#include __bpf_kfunc_start_defs(); @@ -92,6 +93,42 @@ __bpf_kfunc int bpf_path_d_path(struct path *path, char *buf, size_t buf__sz) return len; } +/** + * bpf_get_file_xattr - get xattr of a file + * @file: file to get xattr from + * @name__str: name of the xattr + * @value_p: output buffer of the xattr value + * + * Get xattr *name__str* of *file* and store the output in *value_ptr*. + * + * For security reasons, only *name__str* with prefix "user." is allowed. + * + * Return: 0 on success, a negative value on error. + */ +__bpf_kfunc int bpf_get_file_xattr(struct file *file, const char *name__str, + struct bpf_dynptr *value_p) +{ + struct bpf_dynptr_kern *value_ptr = (struct bpf_dynptr_kern *)value_p; + struct dentry *dentry; + u32 value_len; + void *value; + int ret; + + if (strncmp(name__str, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) + return -EPERM; + + value_len = __bpf_dynptr_size(value_ptr); + value = __bpf_dynptr_data_rw(value_ptr, value_len); + if (!value) + return -EINVAL; + + dentry = file_dentry(file); + ret = inode_permission(&nop_mnt_idmap, dentry->d_inode, MAY_READ); + if (ret) + return ret; + return __vfs_getxattr(dentry, dentry->d_inode, name__str, value, value_len); +} + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(bpf_fs_kfunc_set_ids) @@ -99,6 +136,7 @@ BTF_ID_FLAGS(func, bpf_get_task_exe_file, KF_ACQUIRE | KF_TRUSTED_ARGS | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_put_file, KF_RELEASE) BTF_ID_FLAGS(func, bpf_path_d_path, KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_get_file_xattr, KF_SLEEPABLE | KF_TRUSTED_ARGS) BTF_KFUNCS_END(bpf_fs_kfunc_set_ids) static int bpf_fs_kfuncs_filter(const struct bpf_prog *prog, u32 kfunc_id) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index cd098846e251..d557bb11e0ff 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -24,7 +24,6 @@ #include #include #include -#include #include @@ -1439,73 +1438,6 @@ static int __init bpf_key_sig_kfuncs_init(void) late_initcall(bpf_key_sig_kfuncs_init); #endif /* CONFIG_KEYS */ -/* filesystem kfuncs */ -__bpf_kfunc_start_defs(); - -/** - * bpf_get_file_xattr - get xattr of a file - * @file: file to get xattr from - * @name__str: name of the xattr - * @value_p: output buffer of the xattr value - * - * Get xattr *name__str* of *file* and store the output in *value_ptr*. - * - * For security reasons, only *name__str* with prefix "user." is allowed. - * - * Return: 0 on success, a negative value on error. - */ -__bpf_kfunc int bpf_get_file_xattr(struct file *file, const char *name__str, - struct bpf_dynptr *value_p) -{ - struct bpf_dynptr_kern *value_ptr = (struct bpf_dynptr_kern *)value_p; - struct dentry *dentry; - u32 value_len; - void *value; - int ret; - - if (strncmp(name__str, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) - return -EPERM; - - value_len = __bpf_dynptr_size(value_ptr); - value = __bpf_dynptr_data_rw(value_ptr, value_len); - if (!value) - return -EINVAL; - - dentry = file_dentry(file); - ret = inode_permission(&nop_mnt_idmap, dentry->d_inode, MAY_READ); - if (ret) - return ret; - return __vfs_getxattr(dentry, dentry->d_inode, name__str, value, value_len); -} - -__bpf_kfunc_end_defs(); - -BTF_KFUNCS_START(fs_kfunc_set_ids) -BTF_ID_FLAGS(func, bpf_get_file_xattr, KF_SLEEPABLE | KF_TRUSTED_ARGS) -BTF_KFUNCS_END(fs_kfunc_set_ids) - -static int bpf_get_file_xattr_filter(const struct bpf_prog *prog, u32 kfunc_id) -{ - if (!btf_id_set8_contains(&fs_kfunc_set_ids, kfunc_id)) - return 0; - - /* Only allow to attach from LSM hooks, to avoid recursion */ - return prog->type != BPF_PROG_TYPE_LSM ? -EACCES : 0; -} - -static const struct btf_kfunc_id_set bpf_fs_kfunc_set = { - .owner = THIS_MODULE, - .set = &fs_kfunc_set_ids, - .filter = bpf_get_file_xattr_filter, -}; - -static int __init bpf_fs_kfuncs_init(void) -{ - return register_btf_kfunc_id_set(BPF_PROG_TYPE_LSM, &bpf_fs_kfunc_set); -} - -late_initcall(bpf_fs_kfuncs_init); - static const struct bpf_func_proto * bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) {