| 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: nfsd4: permit read opens of executable-only files |
| |
| 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) |
