VFS: Fix access("file", X_OK) in the presence of ACLs
Currently, the access() call will return incorrect information on NFS if
there exists an ACL that grants execute access to the user on a regular
file. The reason the information is incorrect is that the VFS overrides
this execute access in open_exec() by checking (inode->i_mode & 0111).
This patch propagates the VFS execute bit check back into the generic
permission() call.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 64cbae98848c4c99851cb0a405f0b4982cd76c1e commit)
diff --git a/fs/namei.c b/fs/namei.c
index 8631664..432d6bc 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -227,10 +227,10 @@
int permission(struct inode *inode, int mask, struct nameidata *nd)
{
+ umode_t mode = inode->i_mode;
int retval, submask;
if (mask & MAY_WRITE) {
- umode_t mode = inode->i_mode;
/*
* Nobody gets write access to a read-only fs.
@@ -247,6 +247,13 @@
}
+ /*
+ * MAY_EXEC on regular files requires special handling: We override
+ * filesystem execute permissions if the mode bits aren't set.
+ */
+ if ((mask & MAY_EXEC) && S_ISREG(mode) && !(mode & S_IXUGO))
+ return -EACCES;
+
/* Ordinary permission routines do not understand MAY_APPEND. */
submask = mask & ~MAY_APPEND;
if (inode->i_op && inode->i_op->permission)