From a043226bc140a2c1dde162246d68a67e5043e6b2 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" <bfields@redhat.com> Date: Thu, 25 Aug 2011 10:48:39 -0400 Subject: [PATCH] nfsd4: permit read opens of executable-only files A client that wants to execute a file must be able to read it. Read opens over nfs are therefore implicitly allowed for executable files even when those files are not readable. NFSv2/v3 get this right by using a passed-in NFSD_MAY_OWNER_OVERRIDE on read requests, but NFSv4 has gotten this wrong ever since dc730e173785e29b297aa605786c94adaffe2544 "nfsd4: fix owner-override on open", when we realized that the file owner shouldn't override permissions on non-reclaim NFSv4 opens. So we can't use NFSD_MAY_OWNER_OVERRIDE to tell nfsd_permission to allow reads of executable files. So, do the same thing we do whenever we encounter another weird NFS permission nit: define yet another NFSD_MAY_* flag. The industry's future standardization on 128-bit processors will be motivated primarily by the need for integers with enough bits for all the NFSD_MAY_* flags. Reported-by: Leonardo Borda <leonardoborda@gmail.com> Cc: stable@kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com> --- fs/nfsd/nfs4proc.c | 2 ++ fs/nfsd/vfs.c | 3 ++- fs/nfsd/vfs.h | 1 + 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 479ffb185df9..b5530984db91 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -156,6 +156,8 @@ do_open_permission(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfs !(open->op_share_access & NFS4_SHARE_ACCESS_WRITE)) return nfserr_inval; + accmode |= NFSD_MAY_READ_IF_EXEC; + if (open->op_share_access & NFS4_SHARE_ACCESS_READ) accmode |= NFSD_MAY_READ; if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 4c22870293e6..75c35fa46155 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -2116,7 +2116,8 @@ nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp, /* Allow read access to binaries even when mode 111 */ if (err == -EACCES && S_ISREG(inode->i_mode) && - acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE)) + (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) || + acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC))) err = inode_permission(inode, MAY_EXEC); return err? nfserrno(err) : 0; diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h index e0bbac04d1dd..a22e40e27861 100644 --- a/fs/nfsd/vfs.h +++ b/fs/nfsd/vfs.h @@ -25,6 +25,7 @@ #define NFSD_MAY_BYPASS_GSS_ON_ROOT 256 #define NFSD_MAY_NOT_BREAK_LEASE 512 #define NFSD_MAY_BYPASS_GSS 1024 +#define NFSD_MAY_READ_IF_EXEC 2048 #define NFSD_MAY_CREATE (NFSD_MAY_EXEC|NFSD_MAY_WRITE) #define NFSD_MAY_REMOVE (NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC)