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authorJ. Bruce Fields <bfields@redhat.com>2011-08-25 10:48:39 -0400
committerJ. Bruce Fields <bfields@redhat.com>2011-08-27 14:20:20 -0400
commita043226bc140a2c1dde162246d68a67e5043e6b2 (patch)
tree8d2f2a52835d37150c0cae42787903793e57bd86
parentc10bd39d800d42adef55ed9016f802677cd0ab5f (diff)
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>
-rw-r--r--fs/nfsd/nfs4proc.c2
-rw-r--r--fs/nfsd/vfs.c3
-rw-r--r--fs/nfsd/vfs.h1
3 files changed, 5 insertions, 1 deletions
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)