| Date | Wed, 09 Nov 2011 13:32:43 -0800 | From | Greg KH <> | Subject | [116/264] nfsd4: permit read opens of executable-only files |
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3.1-stable review patch. If anyone has any objections, please let me know.
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From: "J. Bruce Fields" <bfields@redhat.com>
commit a043226bc140a2c1dde162246d68a67e5043e6b2 upstream.
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> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/nfsd/nfs4proc.c | 2 ++ fs/nfsd/vfs.c | 3 ++- fs/nfsd/vfs.h | 1 + 3 files changed, 5 insertions(+), 1 deletion(-)
--- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -156,6 +156,8 @@ do_open_permission(struct svc_rqst *rqst !(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) --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -2114,7 +2114,8 @@ nfsd_permission(struct svc_rqst *rqstp, /* 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; --- 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)
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