From 88c0bdee31a467bb55a3f812b6ae63dae4330a79 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" 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 Cc: stable@kernel.org Signed-off-by: J. Bruce Fields (cherry picked from commit a043226bc140a2c1dde162246d68a67e5043e6b2) BugLink: http://bugs.launchpad.net/bugs/833300 Conflicts: fs/nfsd/vfs.h --- fs/nfsd/nfs4proc.c | 2 ++ fs/nfsd/vfs.c | 3 ++- include/linux/nfsd/nfsd.h | 1 + 3 files changed, 5 insertions(+), 1 deletions(-) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 01d83a5..f865116 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -166,6 +166,8 @@ 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 2e09588..494350b 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -2118,7 +2118,8 @@ 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); if (err) goto nfsd_out; diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h index 510ffdd..3436ec6 100644 --- a/include/linux/nfsd/nfsd.h +++ b/include/linux/nfsd/nfsd.h @@ -38,6 +38,7 @@ #define NFSD_MAY_OWNER_OVERRIDE 64 #define NFSD_MAY_LOCAL_ACCESS 128 /* IRIX doing local access check on device special file*/ #define NFSD_MAY_BYPASS_GSS_ON_ROOT 256 +#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) -- 1.7.5.4