From: "J. Bruce Fields" Subject: [PATCH] nfsd: nfsd should drop CAP_MKNOD for non-root Date: Wed, 18 Mar 2009 12:21:32 -0400 Message-ID: <1237393292-14934-3-git-send-email-bfields@fieldses.org> References: <1237393292-14934-1-git-send-email-bfields@fieldses.org> <1237393292-14934-2-git-send-email-bfields@fieldses.org> Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Igor Zhbanov , Serge Hallyn , "J. Bruce Fields" , stable@kernel.org To: Linus Torvalds Return-path: Received: from mail.fieldses.org ([141.211.133.115]:49036 "EHLO pickle.fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750981AbZCRQVj (ORCPT ); Wed, 18 Mar 2009 12:21:39 -0400 In-Reply-To: <1237393292-14934-2-git-send-email-bfields@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: From: J. Bruce Fields Since creating a device node is normally an operation requiring special privilege, Igor Zhbanov points out that it is surprising (to say the least) that a client can, for example, create a device node on a filesystem exported with root_squash. So, make sure CAP_MKNOD is among the capabilities dropped when an nfsd thread handles a request from a non-root user. Reported-by: Igor Zhbanov Cc: stable@kernel.org Signed-off-by: J. Bruce Fields --- include/linux/capability.h | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/capability.h b/include/linux/capability.h index 1b98725..4864a43 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -393,8 +393,10 @@ struct cpu_vfs_cap_data { # define CAP_FULL_SET ((kernel_cap_t){{ ~0, ~0 }}) # define CAP_INIT_EFF_SET ((kernel_cap_t){{ ~CAP_TO_MASK(CAP_SETPCAP), ~0 }}) # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0, CAP_FS_MASK_B1 } }) -# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0|CAP_TO_MASK(CAP_SYS_RESOURCE), \ - CAP_FS_MASK_B1 } }) +# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ + | CAP_TO_MASK(CAP_SYS_RESOURCE) \ + | CAP_TO_MASK(CAP_MKNOD), \ + CAP_FS_MASK_B1 } }) #endif /* _KERNEL_CAPABILITY_U32S != 2 */ -- 1.6.0.4