Return-Path: Received: from mail-qk0-f193.google.com ([209.85.220.193]:44562 "EHLO mail-qk0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727055AbeHRAtM (ORCPT ); Fri, 17 Aug 2018 20:49:12 -0400 Received: by mail-qk0-f193.google.com with SMTP id p15-v6so5434052qke.11 for ; Fri, 17 Aug 2018 14:44:08 -0700 (PDT) From: Laura Abbott To: "J. Bruce Fields" , Jeff Layton , Trond Myklebust , Anna Schumaker Cc: Laura Abbott , "David S. Miller" , linux-nfs@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] sunrpc: Don't use stack buffer with scatterlist Date: Fri, 17 Aug 2018 14:43:54 -0700 Message-Id: <20180817214354.5780-1-labbott@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Fedora got a bug report from NFS: kernel BUG at include/linux/scatterlist.h:143! ... RIP: 0010:sg_init_one+0x7d/0x90 .. make_checksum+0x4e7/0x760 [rpcsec_gss_krb5] gss_get_mic_kerberos+0x26e/0x310 [rpcsec_gss_krb5] gss_marshal+0x126/0x1a0 [auth_rpcgss] ? __local_bh_enable_ip+0x80/0xe0 ? call_transmit_status+0x1d0/0x1d0 [sunrpc] call_transmit+0x137/0x230 [sunrpc] __rpc_execute+0x9b/0x490 [sunrpc] rpc_run_task+0x119/0x150 [sunrpc] nfs4_run_exchange_id+0x1bd/0x250 [nfsv4] _nfs4_proc_exchange_id+0x2d/0x490 [nfsv4] nfs41_discover_server_trunking+0x1c/0xa0 [nfsv4] nfs4_discover_server_trunking+0x80/0x270 [nfsv4] nfs4_init_client+0x16e/0x240 [nfsv4] ? nfs_get_client+0x4c9/0x5d0 [nfs] ? _raw_spin_unlock+0x24/0x30 ? nfs_get_client+0x4c9/0x5d0 [nfs] nfs4_set_client+0xb2/0x100 [nfsv4] nfs4_create_server+0xff/0x290 [nfsv4] nfs4_remote_mount+0x28/0x50 [nfsv4] mount_fs+0x3b/0x16a vfs_kern_mount.part.35+0x54/0x160 nfs_do_root_mount+0x7f/0xc0 [nfsv4] nfs4_try_mount+0x43/0x70 [nfsv4] ? get_nfs_version+0x21/0x80 [nfs] nfs_fs_mount+0x789/0xbf0 [nfs] ? pcpu_alloc+0x6ca/0x7e0 ? nfs_clone_super+0x70/0x70 [nfs] ? nfs_parse_mount_options+0xb40/0xb40 [nfs] mount_fs+0x3b/0x16a vfs_kern_mount.part.35+0x54/0x160 do_mount+0x1fd/0xd50 ksys_mount+0xba/0xd0 __x64_sys_mount+0x21/0x30 do_syscall_64+0x60/0x1f0 entry_SYSCALL_64_after_hwframe+0x49/0xbe This is BUG_ON(!virt_addr_valid(buf)) triggered by using a stack allocated buffer with a scatterlist. Convert the buffer for rc4salt to be dynamically allocated instead. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1615258 Signed-off-by: Laura Abbott --- Compile tested only. --- net/sunrpc/auth_gss/gss_krb5_crypto.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c index 8654494b4d0a..834eb2b9e41b 100644 --- a/net/sunrpc/auth_gss/gss_krb5_crypto.c +++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c @@ -169,7 +169,7 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen, struct scatterlist sg[1]; int err = -1; u8 *checksumdata; - u8 rc4salt[4]; + u8 *rc4salt; struct crypto_ahash *md5; struct crypto_ahash *hmac_md5; struct ahash_request *req; @@ -183,14 +183,18 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen, return GSS_S_FAILURE; } + rc4salt = kmalloc_array(4, sizeof(*rc4salt), GFP_NOFS); + if (!rc4salt) + return GSS_S_FAILURE; + if (arcfour_hmac_md5_usage_to_salt(usage, rc4salt)) { dprintk("%s: invalid usage value %u\n", __func__, usage); - return GSS_S_FAILURE; + goto out_free_rc4salt; } checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_NOFS); if (!checksumdata) - return GSS_S_FAILURE; + goto out_free_rc4salt; md5 = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC); if (IS_ERR(md5)) @@ -258,6 +262,8 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen, crypto_free_ahash(md5); out_free_cksum: kfree(checksumdata); +out_free_rc4salt: + kfree(rc4salt); return err ? GSS_S_FAILURE : 0; } -- 2.17.1