From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793969964; b=R0j/LTMNKwV9ZlEMaA8oGtIZWXGTrTx2xRteIuF+ekPZPWl0Dt6T0RCsJ+ya0QHDD5Oa wJJ7NHnz5BysrfaGTsyLdwFj7aqLgIVPfax7LZ53uNIPiMTWMyPUZatWcchaXKDylP29j DHE1caqr9gP5quD3WngAlvrooyE+Dqe7Q96kH6Dm8fhwcV3RlweoMaWpzNrs2/ZY/WnAh IcYADCZb7gbuEuDxMyjBBMWqLhifUof/UCOCmBRrL2VZlCAdSuKHSFcg0XegpooTvzt/o 1yW8ZTis88DupkDIfHQ90VHzF0s+W3IEjTa9G3Wx3KhvXdtiZH720/F7k71Sb0uLY4A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793969964; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=fiYwLEHB3UDkX1HTg9ZN8aoSra0A2vaRIEd4CmgIwKs=; b=SRanHVdYnsHv/0dKIoiZdB45q62f7VSYUNlqMKCY0O3tv5XmkbjVSxY9YnWSBXHDBTV3 mi2ZL3QmBpGDGDgcxQ0lYASHotd9ZkpjBEDD7u4PtS/ts1ztVFEf61IAYikm1jfDrQJw4 owd8Iu4XXWplbla+5TuQEriP6euKx/0yzvTBeuaTsNtSyUp7OxYDr5Sf7tLVVuf3ZD1uy t2+mKLSUNEjOuRaosauBwf1pbpEbYyfd6MhIu4NxVUMrqRN2lNrRVWjND+Tiv1MapIob+ hqoNeP6w/KgrGh3aiy6PI0XiMECB6pBVKkm2d5hoAi1Chm6eR3xemgUS3K8O0zdZVrg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=YO6qJheh; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B80DF606A326 for ; Fri, 6 Nov 2026 12:59:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=YO6qJheh Received: by smtp.kernel.org (Postfix) with ESMTPSA id B84C41F0089F; Fri, 6 Nov 2026 12:59:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793969963; bh=fiYwLEHB3UDkX1HTg9ZN8aoSra0A2vaRIEd4CmgIwKs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YO6qJhehT8BcrGBRzr68uboZKbM17seWksY3o5/O1taGOVy45A46lY3Ij23NWipIg 2lqUQttyJHt7CS9igUOfsw1IPW0bO9fP30uKy5D5MV+lLlgkKc00Vq4zOcs79fg6fl qk+RvgEJ//WDYjiOkUTT3UlRpi+ZimsTEEjzO02/UPLUTUs73IDoZX80VahDFrjQMU JFo+012dy8dYrBy4JummquCdDo+VALdkc55y/QTjFrvnwWHlvuWuvnmRsdgo02i9Y3 Pasb3GIuo9n+zfPSHjDHEQ+6PZL7upHRCqThWp6e1usALbdwzuPZ9eu61opoJ/j59V P68BuZEJvD9ng== From: Sasha Levin To: stable@vger.kernel.org Cc: Chuck Lever , sashiko-bot , Jeff Layton , Sasha Levin Subject: [PATCH 6.1.y] NFSD: Map flex file layout IDs through the request's user namespace Date: Fri, 6 Nov 2026 07:59:21 -0500 Message-ID: <20261106125901.15517-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026110409-never-carnation-defe@gregkh> References: <2026110409-never-carnation-defe@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chuck Lever [ Upstream commit f913d5d2130a584d1a027ffe3dfd88b6be2e0540 ] nfsd4_ff_proc_layoutget() and nfsd4_ff_encode_layoutget() translate the file's owner and group with init_user_ns, but every other identity nfsd places on the wire goes through nfsd_user_namespace(). When the transport carries a credential from a non-initial user namespace, the flex file layout reports host-global IDs. The client copies those IDs into the AUTH_SYS credential it presents to the data server, and svcauth_unix_accept() resolves that credential in the transport's namespace, so data server I/O runs under an identity unrelated to the file's owner. Switching to the request's namespace introduces a second hazard. from_kuid() returns (uid_t)-1 when the target namespace has no mapping for the owner, and the IOMODE_READ arm adds one to that result to derive an identity for which the data server denies writes. The addition would wrap to zero, handing the client uid 0 instead of an identity distinct from the owner. Translate both IDs in nfsd4_ff_proc_layoutget(), which has the svc_rqst, and carry the wire values in struct pnfs_ff_layout. from_kuid_munged() substitutes overflowuid for an unmapped owner and thus never returns (uid_t)-1, so the increment cannot wrap to zero. Fixes: 9b9960a0ca47 ("nfsd: Add a super simple flex file server") Cc: stable@vger.kernel.org Reported-by: sashiko-bot Closes: https://sashiko.dev/#/patchset/20260720141442.783935-1-cel@kernel.org?part=3 Reviewed-by: Jeff Layton Link: https://patch.msgid.link/20260720163724.810227-1-cel@kernel.org Signed-off-by: Chuck Lever [ sashal: added the missing rqstp argument to the proc_layoutget callback interface, caller and implementations ] Signed-off-by: Sasha Levin --- fs/nfsd/blocklayout.c | 4 ++-- fs/nfsd/flexfilelayout.c | 24 ++++++++++++++---------- fs/nfsd/flexfilelayoutxdr.c | 4 ++-- fs/nfsd/flexfilelayoutxdr.h | 5 +++-- fs/nfsd/nfs4proc.c | 2 +- fs/nfsd/pnfs.h | 4 ++-- 6 files changed, 24 insertions(+), 19 deletions(-) diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c index 5eae60425e57c..bbb999c9bab99 100644 --- a/fs/nfsd/blocklayout.c +++ b/fs/nfsd/blocklayout.c @@ -18,8 +18,8 @@ static __be32 -nfsd4_block_proc_layoutget(struct inode *inode, const struct svc_fh *fhp, - struct nfsd4_layoutget *args) +nfsd4_block_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode, + const struct svc_fh *fhp, struct nfsd4_layoutget *args) { struct nfsd4_layout_seg *seg = &args->lg_seg; struct super_block *sb = inode->i_sb; diff --git a/fs/nfsd/flexfilelayout.c b/fs/nfsd/flexfilelayout.c index 0bc52e6bec394..3c6a80c010957 100644 --- a/fs/nfsd/flexfilelayout.c +++ b/fs/nfsd/flexfilelayout.c @@ -14,19 +14,20 @@ #include #include "flexfilelayoutxdr.h" +#include "auth.h" #include "pnfs.h" #include "vfs.h" #define NFSDDBG_FACILITY NFSDDBG_PNFS static __be32 -nfsd4_ff_proc_layoutget(struct inode *inode, const struct svc_fh *fhp, - struct nfsd4_layoutget *args) +nfsd4_ff_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode, + const struct svc_fh *fhp, struct nfsd4_layoutget *args) { + struct user_namespace *userns = nfsd_user_namespace(rqstp); struct nfsd4_layout_seg *seg = &args->lg_seg; u32 device_generation = 0; int error; - uid_t u; struct pnfs_ff_layout *fl; @@ -49,13 +50,16 @@ nfsd4_ff_proc_layoutget(struct inode *inode, const struct svc_fh *fhp, fl->flags = FF_FLAGS_NO_LAYOUTCOMMIT | FF_FLAGS_NO_IO_THRU_MDS | FF_FLAGS_NO_READ_IO; - /* Do not allow a IOMODE_READ segment to have write pemissions */ - if (seg->iomode == IOMODE_READ) { - u = from_kuid(&init_user_ns, inode->i_uid) + 1; - fl->uid = make_kuid(&init_user_ns, u); - } else - fl->uid = inode->i_uid; - fl->gid = inode->i_gid; + fl->uid = from_kuid_munged(userns, inode->i_uid); + fl->gid = from_kgid_munged(userns, inode->i_gid); + + /* + * Do not allow an IOMODE_READ segment to have write permissions. + * The group is left intact so group-readable files stay readable; + * nfsd_setuser() squashes an unmapped uid to the export's anon ID. + */ + if (seg->iomode == IOMODE_READ) + fl->uid++; error = nfsd4_set_deviceid(&fl->deviceid, fhp, device_generation); if (error) diff --git a/fs/nfsd/flexfilelayoutxdr.c b/fs/nfsd/flexfilelayoutxdr.c index c05d1d3e20210..4bfdfee1bf9ce 100644 --- a/fs/nfsd/flexfilelayoutxdr.c +++ b/fs/nfsd/flexfilelayoutxdr.c @@ -32,8 +32,8 @@ nfsd4_ff_encode_layoutget(struct xdr_stream *xdr, fh_len = 4 + xdr_align_size(fl->fh.size); - uid.len = sprintf(uid.buf, "%u", from_kuid(&init_user_ns, fl->uid)); - gid.len = sprintf(gid.buf, "%u", from_kgid(&init_user_ns, fl->gid)); + uid.len = sprintf(uid.buf, "%u", fl->uid); + gid.len = sprintf(gid.buf, "%u", fl->gid); /* data server entry: deviceid + efficiency + stateid + fh list + * user + group + flags + stats_collect_hint diff --git a/fs/nfsd/flexfilelayoutxdr.h b/fs/nfsd/flexfilelayoutxdr.h index 8e195aeca0237..3e2dc4d070f8d 100644 --- a/fs/nfsd/flexfilelayoutxdr.h +++ b/fs/nfsd/flexfilelayoutxdr.h @@ -35,8 +35,9 @@ struct pnfs_ff_device_addr { struct pnfs_ff_layout { u32 flags; u32 stats_collect_hint; - kuid_t uid; - kgid_t gid; + /* Values to encode; nfsd4_ff_proc_layoutget() has mapped these */ + u32 uid; + u32 gid; struct nfsd4_deviceid deviceid; stateid_t stateid; struct nfs_fh fh; diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 3af22badd70f5..9bad4740101fa 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -2260,7 +2260,7 @@ nfsd4_layoutget(struct svc_rqst *rqstp, if (atomic_read(&ls->ls_stid.sc_file->fi_lo_recalls)) goto out_put_stid; - nfserr = ops->proc_layoutget(d_inode(current_fh->fh_dentry), + nfserr = ops->proc_layoutget(rqstp, d_inode(current_fh->fh_dentry), current_fh, lgp); if (nfserr) goto out_put_stid; diff --git a/fs/nfsd/pnfs.h b/fs/nfsd/pnfs.h index 4f4282d4eeca4..c29de1795b2cb 100644 --- a/fs/nfsd/pnfs.h +++ b/fs/nfsd/pnfs.h @@ -29,8 +29,8 @@ struct nfsd4_layout_ops { __be32 (*encode_getdeviceinfo)(struct xdr_stream *xdr, struct nfsd4_getdeviceinfo *gdevp); - __be32 (*proc_layoutget)(struct inode *, const struct svc_fh *fhp, - struct nfsd4_layoutget *lgp); + __be32 (*proc_layoutget)(struct svc_rqst *rqstp, struct inode *inode, + const struct svc_fh *fhp, struct nfsd4_layoutget *lgp); __be32 (*encode_layoutget)(struct xdr_stream *, struct nfsd4_layoutget *lgp); -- 2.53.0