From patchwork Thu Sep 2 22:17:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namjae Jeon X-Patchwork-Id: 1523944 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4H0wK44dgTz9s5R for ; Fri, 3 Sep 2021 08:17:28 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239995AbhIBWSZ (ORCPT ); Thu, 2 Sep 2021 18:18:25 -0400 Received: from mail-pg1-f178.google.com ([209.85.215.178]:41804 "EHLO mail-pg1-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236148AbhIBWSX (ORCPT ); Thu, 2 Sep 2021 18:18:23 -0400 Received: by mail-pg1-f178.google.com with SMTP id k24so3500737pgh.8 for ; Thu, 02 Sep 2021 15:17:25 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=wCqEj2nnHQT5+ADuGnUZQcy//wo+tJxTophT3J3eoHE=; b=mBGALrScUCUb9U3v69vfR0MmnBYDhLIll+RY7Ws9nJzMAom3G7l/jscBg/jgJevnEk bz1MaBQw1ALcGL/N96bVPNNVadv+0TLHT5jDdSTzlv3aYmu4niovmzgzfRYt+uTiGxjU gaGfB3+zEDAEe/UNAkSdat5P9wWA8cIS9c3d0JoiFa4PxFeJIxGIp8GurnCSz6IVIZBK ZFBnbpxICh6MK01XcBYrzGzvNxjWWoLGa3TbY53wkP8wz82N1U2t5n8eAx6HRGltfusW PCg++dTjQQLaJR11YcSyUjY8gAxCXPNdyQwh3AAg6GSxP/UcI3UgLmeFN6JauB4VQvwv rLhA== X-Gm-Message-State: AOAM5339gVb+d97y4hY/bGJwrGX4drx8Z3LGi0QE5eutYHaa9Lz+7HeP /rWpVdRt46oxpZvy0ZPRNyGA30jwrh555Q== X-Google-Smtp-Source: ABdhPJwMCAajtlOrg+A+RG42/sMkopz4QmNaj69ilT8C2Yxtdg48E/MF6TpYLFFQ2NizxTHuVaA+iQ== X-Received: by 2002:a63:4f0d:: with SMTP id d13mr532971pgb.169.1630621044549; Thu, 02 Sep 2021 15:17:24 -0700 (PDT) Received: from localhost.localdomain ([61.74.27.164]) by smtp.gmail.com with ESMTPSA id o1sm3207699pjk.1.2021.09.02.15.17.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Sep 2021 15:17:24 -0700 (PDT) From: Namjae Jeon To: linux-cifs@vger.kernel.org Cc: Namjae Jeon , Dan Carpenter Subject: [PATCH v2] ksmbd: add validation for ndr read/write functions Date: Fri, 3 Sep 2021 07:17:05 +0900 Message-Id: <20210902221705.5296-1-linkinjeon@kernel.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org If ndr->length is smaller than expected size, ksmbd can access invalid access in ndr->data. This patch add validation to check ndr->offset is over ndr->length. and added exception handling to check return value of ndr read/write function. Cc: Dan Carpenter Signed-off-by: Namjae Jeon --- v2: - change data type of "ret" to int in ndr_decode_dos_attr(). fs/ksmbd/ndr.c | 383 +++++++++++++++++++++++++++++++++++-------------- 1 file changed, 274 insertions(+), 109 deletions(-) diff --git a/fs/ksmbd/ndr.c b/fs/ksmbd/ndr.c index e6a574fa7709..a476de291f62 100644 --- a/fs/ksmbd/ndr.c +++ b/fs/ksmbd/ndr.c @@ -28,37 +28,60 @@ static int try_to_realloc_ndr_blob(struct ndr *n, size_t sz) return 0; } -static void ndr_write_int16(struct ndr *n, __u16 value) +static int ndr_write_int16(struct ndr *n, __u16 value) { - if (n->length <= n->offset + sizeof(value)) - try_to_realloc_ndr_blob(n, sizeof(value)); + if (n->length <= n->offset + sizeof(value)) { + int ret; + + ret = try_to_realloc_ndr_blob(n, sizeof(value)); + if (ret) + return ret; + } *(__le16 *)ndr_get_field(n) = cpu_to_le16(value); n->offset += sizeof(value); + return 0; } -static void ndr_write_int32(struct ndr *n, __u32 value) +static int ndr_write_int32(struct ndr *n, __u32 value) { - if (n->length <= n->offset + sizeof(value)) - try_to_realloc_ndr_blob(n, sizeof(value)); + if (n->length <= n->offset + sizeof(value)) { + int ret; + + ret = try_to_realloc_ndr_blob(n, sizeof(value)); + if (ret) + return ret; + } *(__le32 *)ndr_get_field(n) = cpu_to_le32(value); n->offset += sizeof(value); + return 0; } -static void ndr_write_int64(struct ndr *n, __u64 value) +static int ndr_write_int64(struct ndr *n, __u64 value) { - if (n->length <= n->offset + sizeof(value)) - try_to_realloc_ndr_blob(n, sizeof(value)); + if (n->length <= n->offset + sizeof(value)) { + int ret; + + ret = try_to_realloc_ndr_blob(n, sizeof(value)); + if (ret) + return ret; + } *(__le64 *)ndr_get_field(n) = cpu_to_le64(value); n->offset += sizeof(value); + return 0; } static int ndr_write_bytes(struct ndr *n, void *value, size_t sz) { - if (n->length <= n->offset + sz) - try_to_realloc_ndr_blob(n, sz); + if (n->length <= n->offset + sz) { + int ret; + + ret = try_to_realloc_ndr_blob(n, sz); + if (ret) + return ret; + } memcpy(ndr_get_field(n), value, sz); n->offset += sz; @@ -70,8 +93,13 @@ static int ndr_write_string(struct ndr *n, char *value) size_t sz; sz = strlen(value) + 1; - if (n->length <= n->offset + sz) - try_to_realloc_ndr_blob(n, sz); + if (n->length <= n->offset + sz) { + int ret; + + ret = try_to_realloc_ndr_blob(n, sz); + if (ret) + return ret; + } memcpy(ndr_get_field(n), value, sz); n->offset += sz; @@ -81,9 +109,14 @@ static int ndr_write_string(struct ndr *n, char *value) static int ndr_read_string(struct ndr *n, void *value, size_t sz) { - int len = strnlen(ndr_get_field(n), sz); + int len; - memcpy(value, ndr_get_field(n), len); + if (n->offset + sz > n->length) + return -EINVAL; + + len = strnlen(ndr_get_field(n), sz); + if (value) + memcpy(value, ndr_get_field(n), len); len++; n->offset += len; n->offset = ALIGN(n->offset, 2); @@ -92,41 +125,52 @@ static int ndr_read_string(struct ndr *n, void *value, size_t sz) static int ndr_read_bytes(struct ndr *n, void *value, size_t sz) { - memcpy(value, ndr_get_field(n), sz); + if (n->offset + sz > n->length) + return -EINVAL; + + if (value) + memcpy(value, ndr_get_field(n), sz); n->offset += sz; return 0; } -static __u16 ndr_read_int16(struct ndr *n) +static int ndr_read_int16(struct ndr *n, __u16 *value) { - __u16 ret; + if (n->offset + sizeof(__u16) > n->length) + return -EINVAL; - ret = le16_to_cpu(*(__le16 *)ndr_get_field(n)); + if (value) + *value = le16_to_cpu(*(__le16 *)ndr_get_field(n)); n->offset += sizeof(__u16); - return ret; + return 0; } -static __u32 ndr_read_int32(struct ndr *n) +static int ndr_read_int32(struct ndr *n, __u32 *value) { - __u32 ret; + if (n->offset + sizeof(__u32) > n->length) + return 0; - ret = le32_to_cpu(*(__le32 *)ndr_get_field(n)); + if (value) + *value = le32_to_cpu(*(__le32 *)ndr_get_field(n)); n->offset += sizeof(__u32); - return ret; + return 0; } -static __u64 ndr_read_int64(struct ndr *n) +static int ndr_read_int64(struct ndr *n, __u64 *value) { - __u64 ret; + if (n->offset + sizeof(__u64) > n->length) + return -EINVAL; - ret = le64_to_cpu(*(__le64 *)ndr_get_field(n)); + if (value) + *value = le64_to_cpu(*(__le64 *)ndr_get_field(n)); n->offset += sizeof(__u64); - return ret; + return 0; } int ndr_encode_dos_attr(struct ndr *n, struct xattr_dos_attrib *da) { char hex_attr[12] = {0}; + int ret; n->offset = 0; n->length = 1024; @@ -136,97 +180,161 @@ int ndr_encode_dos_attr(struct ndr *n, struct xattr_dos_attrib *da) if (da->version == 3) { snprintf(hex_attr, 10, "0x%x", da->attr); - ndr_write_string(n, hex_attr); + ret = ndr_write_string(n, hex_attr); } else { - ndr_write_string(n, ""); + ret = ndr_write_string(n, ""); } - ndr_write_int16(n, da->version); - ndr_write_int32(n, da->version); + if (ret) + return ret; + + ret = ndr_write_int16(n, da->version); + if (ret) + return ret; + + ret = ndr_write_int32(n, da->version); + if (ret) + return ret; + + ret = ndr_write_int32(n, da->flags); + if (ret) + return ret; + + ret = ndr_write_int32(n, da->attr); + if (ret) + return ret; - ndr_write_int32(n, da->flags); - ndr_write_int32(n, da->attr); if (da->version == 3) { - ndr_write_int32(n, da->ea_size); - ndr_write_int64(n, da->size); - ndr_write_int64(n, da->alloc_size); + ret = ndr_write_int32(n, da->ea_size); + if (ret) + return ret; + ret = ndr_write_int64(n, da->size); + if (ret) + return ret; + ret = ndr_write_int64(n, da->alloc_size); } else { - ndr_write_int64(n, da->itime); + ret = ndr_write_int64(n, da->itime); } - ndr_write_int64(n, da->create_time); + if (ret) + return ret; + + ret = ndr_write_int64(n, da->create_time); + if (ret) + return ret; + if (da->version == 3) - ndr_write_int64(n, da->change_time); - return 0; + ret = ndr_write_int64(n, da->change_time); + return ret; } int ndr_decode_dos_attr(struct ndr *n, struct xattr_dos_attrib *da) { - char *hex_attr; - int version2; - - hex_attr = kzalloc(n->length, GFP_KERNEL); - if (!hex_attr) - return -ENOMEM; + char hex_attr[12]; + unsigned int version2; + int ret; n->offset = 0; - ndr_read_string(n, hex_attr, n->length); - kfree(hex_attr); - da->version = ndr_read_int16(n); + ret = ndr_read_string(n, hex_attr, sizeof(hex_attr)); + if (ret) + return ret; + + ret = ndr_read_int16(n, &da->version); + if (ret) + return ret; if (da->version != 3 && da->version != 4) { pr_err("v%d version is not supported\n", da->version); return -EINVAL; } - version2 = ndr_read_int32(n); + ret = ndr_read_int32(n, &version2); + if (ret) + return ret; + if (da->version != version2) { pr_err("ndr version mismatched(version: %d, version2: %d)\n", da->version, version2); return -EINVAL; } - ndr_read_int32(n); - da->attr = ndr_read_int32(n); + ret = ndr_read_int32(n, NULL); + if (ret) + return ret; + + ret = ndr_read_int32(n, &da->attr); + if (ret) + return ret; + if (da->version == 4) { - da->itime = ndr_read_int64(n); - da->create_time = ndr_read_int64(n); + ret = ndr_read_int64(n, &da->itime); + if (ret) + return ret; + + ret = ndr_read_int64(n, &da->create_time); } else { - ndr_read_int32(n); - ndr_read_int64(n); - ndr_read_int64(n); - da->create_time = ndr_read_int64(n); - ndr_read_int64(n); + ret = ndr_read_int32(n, NULL); + if (ret) + return ret; + + ndr_read_int64(n, NULL); + if (ret) + return ret; + + ndr_read_int64(n, NULL); + if (ret) + return ret; + + ret = ndr_read_int64(n, &da->create_time); + if (ret) + return ret; + + ret = ndr_read_int64(n, NULL); } - return 0; + return ret; } static int ndr_encode_posix_acl_entry(struct ndr *n, struct xattr_smb_acl *acl) { - int i; + int i, ret; + + ret = ndr_write_int32(n, acl->count); + if (ret) + return ret; - ndr_write_int32(n, acl->count); n->offset = ALIGN(n->offset, 8); - ndr_write_int32(n, acl->count); - ndr_write_int32(n, 0); + ret = ndr_write_int32(n, acl->count); + if (ret) + return ret; + + ret = ndr_write_int32(n, 0); + if (ret) + return ret; for (i = 0; i < acl->count; i++) { n->offset = ALIGN(n->offset, 8); - ndr_write_int16(n, acl->entries[i].type); - ndr_write_int16(n, acl->entries[i].type); + ret = ndr_write_int16(n, acl->entries[i].type); + if (ret) + return ret; + + ret = ndr_write_int16(n, acl->entries[i].type); + if (ret) + return ret; if (acl->entries[i].type == SMB_ACL_USER) { n->offset = ALIGN(n->offset, 8); - ndr_write_int64(n, acl->entries[i].uid); + ret = ndr_write_int64(n, acl->entries[i].uid); } else if (acl->entries[i].type == SMB_ACL_GROUP) { n->offset = ALIGN(n->offset, 8); - ndr_write_int64(n, acl->entries[i].gid); + ret = ndr_write_int64(n, acl->entries[i].gid); } + if (ret) + return ret; /* push permission */ - ndr_write_int32(n, acl->entries[i].perm); + ret = ndr_write_int32(n, acl->entries[i].perm); } - return 0; + return ret; } int ndr_encode_posix_acl(struct ndr *n, @@ -235,7 +343,8 @@ int ndr_encode_posix_acl(struct ndr *n, struct xattr_smb_acl *acl, struct xattr_smb_acl *def_acl) { - int ref_id = 0x00020000; + unsigned int ref_id = 0x00020000; + int ret; n->offset = 0; n->length = 1024; @@ -245,35 +354,46 @@ int ndr_encode_posix_acl(struct ndr *n, if (acl) { /* ACL ACCESS */ - ndr_write_int32(n, ref_id); + ret = ndr_write_int32(n, ref_id); ref_id += 4; } else { - ndr_write_int32(n, 0); + ret = ndr_write_int32(n, 0); } + if (ret) + return ret; if (def_acl) { /* DEFAULT ACL ACCESS */ - ndr_write_int32(n, ref_id); + ret = ndr_write_int32(n, ref_id); ref_id += 4; } else { - ndr_write_int32(n, 0); + ret = ndr_write_int32(n, 0); } - - ndr_write_int64(n, from_kuid(&init_user_ns, i_uid_into_mnt(user_ns, inode))); - ndr_write_int64(n, from_kgid(&init_user_ns, i_gid_into_mnt(user_ns, inode))); - ndr_write_int32(n, inode->i_mode); + if (ret) + return ret; + + ret = ndr_write_int64(n, from_kuid(&init_user_ns, i_uid_into_mnt(user_ns, inode))); + if (ret) + return ret; + ret = ndr_write_int64(n, from_kgid(&init_user_ns, i_gid_into_mnt(user_ns, inode))); + if (ret) + return ret; + ret = ndr_write_int32(n, inode->i_mode); + if (ret) + return ret; if (acl) { - ndr_encode_posix_acl_entry(n, acl); - if (def_acl) - ndr_encode_posix_acl_entry(n, def_acl); + ret = ndr_encode_posix_acl_entry(n, acl); + if (def_acl && !ret) + ret = ndr_encode_posix_acl_entry(n, def_acl); } - return 0; + return ret; } int ndr_encode_v4_ntacl(struct ndr *n, struct xattr_ntacl *acl) { - int ref_id = 0x00020004; + unsigned int ref_id = 0x00020004; + int ret; n->offset = 0; n->length = 2048; @@ -281,36 +401,65 @@ int ndr_encode_v4_ntacl(struct ndr *n, struct xattr_ntacl *acl) if (!n->data) return -ENOMEM; - ndr_write_int16(n, acl->version); - ndr_write_int32(n, acl->version); - ndr_write_int16(n, 2); - ndr_write_int32(n, ref_id); + ret = ndr_write_int16(n, acl->version); + if (ret) + return ret; + + ret = ndr_write_int32(n, acl->version); + if (ret) + return ret; + + ret = ndr_write_int16(n, 2); + if (ret) + return ret; + + ret = ndr_write_int32(n, ref_id); + if (ret) + return ret; /* push hash type and hash 64bytes */ - ndr_write_int16(n, acl->hash_type); - ndr_write_bytes(n, acl->hash, XATTR_SD_HASH_SIZE); - ndr_write_bytes(n, acl->desc, acl->desc_len); - ndr_write_int64(n, acl->current_time); - ndr_write_bytes(n, acl->posix_acl_hash, XATTR_SD_HASH_SIZE); + ret = ndr_write_int16(n, acl->hash_type); + if (ret) + return ret; - /* push ndr for security descriptor */ - ndr_write_bytes(n, acl->sd_buf, acl->sd_size); + ret = ndr_write_bytes(n, acl->hash, XATTR_SD_HASH_SIZE); + if (ret) + return ret; - return 0; + ret = ndr_write_bytes(n, acl->desc, acl->desc_len); + if (ret) + return ret; + + ret = ndr_write_int64(n, acl->current_time); + if (ret) + return ret; + + ret = ndr_write_bytes(n, acl->posix_acl_hash, XATTR_SD_HASH_SIZE); + if (ret) + return ret; + + /* push ndr for security descriptor */ + ret = ndr_write_bytes(n, acl->sd_buf, acl->sd_size); + return ret; } int ndr_decode_v4_ntacl(struct ndr *n, struct xattr_ntacl *acl) { - int version2; + unsigned int version2; + int ret; n->offset = 0; - acl->version = ndr_read_int16(n); + ret = ndr_read_int16(n, &acl->version); + if (ret) + return ret; if (acl->version != 4) { pr_err("v%d version is not supported\n", acl->version); return -EINVAL; } - version2 = ndr_read_int32(n); + ret = ndr_read_int32(n, &version2); + if (ret) + return ret; if (acl->version != version2) { pr_err("ndr version mismatched(version: %d, version2: %d)\n", acl->version, version2); @@ -318,11 +467,22 @@ int ndr_decode_v4_ntacl(struct ndr *n, struct xattr_ntacl *acl) } /* Read Level */ - ndr_read_int16(n); + ret = ndr_read_int16(n, NULL); + if (ret) + return ret; + /* Read Ref Id */ - ndr_read_int32(n); - acl->hash_type = ndr_read_int16(n); - ndr_read_bytes(n, acl->hash, XATTR_SD_HASH_SIZE); + ret = ndr_read_int32(n, NULL); + if (ret) + return ret; + + ret = ndr_read_int16(n, &acl->hash_type); + if (ret) + return ret; + + ret = ndr_read_bytes(n, acl->hash, XATTR_SD_HASH_SIZE); + if (ret) + return ret; ndr_read_bytes(n, acl->desc, 10); if (strncmp(acl->desc, "posix_acl", 9)) { @@ -331,15 +491,20 @@ int ndr_decode_v4_ntacl(struct ndr *n, struct xattr_ntacl *acl) } /* Read Time */ - ndr_read_int64(n); + ret = ndr_read_int64(n, NULL); + if (ret) + return ret; + /* Read Posix ACL hash */ - ndr_read_bytes(n, acl->posix_acl_hash, XATTR_SD_HASH_SIZE); + ret = ndr_read_bytes(n, acl->posix_acl_hash, XATTR_SD_HASH_SIZE); + if (ret) + return ret; + acl->sd_size = n->length - n->offset; acl->sd_buf = kzalloc(acl->sd_size, GFP_KERNEL); if (!acl->sd_buf) return -ENOMEM; - ndr_read_bytes(n, acl->sd_buf, acl->sd_size); - - return 0; + ret = ndr_read_bytes(n, acl->sd_buf, acl->sd_size); + return ret; }