From: Neil Brown Date: Fri, 7 Dec 2012 20:40:55 +0000 (-0500) Subject: nfsd: avoid permission checks on EXCLUSIVE_CREATE replay X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7007c90fb9fef593b4aeaeee57e6a6754276c97c;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git nfsd: avoid permission checks on EXCLUSIVE_CREATE replay With NFSv4, if we create a file then open it we explicit avoid checking the permissions on the file during the open because the fact that we created it ensures we should be allow to open it (the create and the open should appear to be a single operation). However if the reply to an EXCLUSIVE create gets lots and the client resends the create, the current code will perform the permission check - because it doesn't realise that it did the open already.. This patch should fix this. Note that I haven't actually seen this cause a problem. I was just looking at the code trying to figure out a different EXCLUSIVE open related issue, and this looked wrong. (Fix confirmed with pynfs 4.0 test OPEN4--bfields) Cc: stable@kernel.org Signed-off-by: NeilBrown [bfields: use OWNER_OVERRIDE and update for 4.1] Signed-off-by: J. Bruce Fields --- diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 87d24e5f3ca4..1a0b1fdb5ad3 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -195,6 +195,7 @@ static __be32 do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open) { struct svc_fh *resfh; + int accmode; __be32 status; resfh = kmalloc(sizeof(struct svc_fh), GFP_KERNEL); @@ -254,9 +255,10 @@ do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_o /* set reply cache */ fh_copy_shallow(&open->op_openowner->oo_owner.so_replay.rp_openfh, &resfh->fh_handle); - if (!open->op_created) - status = do_open_permission(rqstp, resfh, open, - NFSD_MAY_NOP); + accmode = NFSD_MAY_NOP; + if (open->op_created) + accmode |= NFSD_MAY_OWNER_OVERRIDE; + status = do_open_permission(rqstp, resfh, open, accmode); set_change_info(&open->op_cinfo, current_fh); fh_dup2(current_fh, resfh); out: diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index b584205b25b4..0ef9b6b410a2 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1471,13 +1471,19 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, case NFS3_CREATE_EXCLUSIVE: if ( dchild->d_inode->i_mtime.tv_sec == v_mtime && dchild->d_inode->i_atime.tv_sec == v_atime - && dchild->d_inode->i_size == 0 ) + && dchild->d_inode->i_size == 0 ) { + if (created) + *created = 1; break; + } case NFS4_CREATE_EXCLUSIVE4_1: if ( dchild->d_inode->i_mtime.tv_sec == v_mtime && dchild->d_inode->i_atime.tv_sec == v_atime - && dchild->d_inode->i_size == 0 ) + && dchild->d_inode->i_size == 0 ) { + if (created) + *created = 1; goto set_attr; + } /* fallthru */ case NFS3_CREATE_GUARDED: err = nfserr_exist;