The patch titled
fix execute checking in permission()
has been added to the -mm tree. Its filename is
fix-execute-checking-in-permission.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: fix execute checking in permission()
From: Miklos Szeredi <mszeredi@xxxxxxx>
permission() checks that MAY_EXEC is only allowed on regular files if at least
one execute bit is set in the file mode.
generic_permission() already ensures this, so the extra check in permission()
is superfluous.
If the filesystem defines it's own ->permission() the check may still be
needed. In this case move it after ->permission(). This is needed because
filesystems such as FUSE may need to refresh the inode attributes before
checking permissions.
This check should be moved inside ->permission(), but that's another story.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 36 ++++++++++++++++++++++++------------
1 files changed, 24 insertions(+), 12 deletions(-)
diff -puN fs/namei.c~fix-execute-checking-in-permission fs/namei.c
--- a/fs/namei.c~fix-execute-checking-in-permission
+++ a/fs/namei.c
@@ -227,10 +227,10 @@ int generic_permission(struct inode *ino
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.
@@ -246,22 +246,34 @@ int permission(struct inode *inode, int
return -EACCES;
}
-
- /*
- * MAY_EXEC on regular files requires special handling: We override
- * filesystem execute permissions if the mode bits aren't set or
- * the fs is mounted with the "noexec" flag.
- */
- if ((mask & MAY_EXEC) && S_ISREG(mode) && (!(mode & S_IXUGO) ||
- (nd && nd->mnt && (nd->mnt->mnt_flags & MNT_NOEXEC))))
- return -EACCES;
+ if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
+ /*
+ * MAY_EXEC on regular files is denied if the fs is mounted
+ * with the "noexec" flag.
+ */
+ if (nd && nd->mnt && (nd->mnt->mnt_flags & MNT_NOEXEC))
+ return -EACCES;
+ }
/* Ordinary permission routines do not understand MAY_APPEND. */
submask = mask & ~MAY_APPEND;
- if (inode->i_op && inode->i_op->permission)
+ if (inode->i_op && inode->i_op->permission) {
retval = inode->i_op->permission(inode, submask, nd);
- else
+ if (!retval) {
+ /*
+ * Exec permission on a regular file is denied if none
+ * of the execute bits are set.
+ *
+ * This check should be done by the ->permission()
+ * method.
+ */
+ if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode) &&
+ !(inode->i_mode & S_IXUGO))
+ return -EACCES;
+ }
+ } else {
retval = generic_permission(inode, submask, NULL);
+ }
if (retval)
return retval;
_
Patches currently in -mm which might be from mszeredi@xxxxxxx are
fuse-convert-to-new-aops.patch
ext2-show-all-mount-options.patch
ext3-show-all-mount-options.patch
ext4-show-all-mount-options.patch
vfs-check-nanoseconds-in-utimensat.patch
fix-execute-checking-in-permission.patch
unprivileged-mounts-add-user-mounts-to-the-kernel.patch
unprivileged-mounts-allow-unprivileged-umount.patch
unprivileged-mounts-account-user-mounts.patch
unprivileged-mounts-propagate-error-values-from-clone_mnt.patch
unprivileged-mounts-allow-unprivileged-bind-mounts.patch
unprivileged-mounts-put-declaration-of-put_filesystem-in-fsh.patch
unprivileged-mounts-allow-unprivileged-mounts.patch
unprivileged-mounts-allow-unprivileged-mounts-fix-subtype-handling.patch
unprivileged-mounts-allow-unprivileged-fuse-mounts.patch
unprivileged-mounts-propagation-inherit-owner-from-parent.patch
unprivileged-mounts-propagation-inherit-owner-from-parent-fix-for-git-audit.patch
unprivileged-mounts-add-no-submounts-flag.patch
fuse-update-backing_dev_info-congestion-state.patch
fuse-fix-reserved-request-wake-up.patch
fuse-add-reference-counting-to-fuse_file.patch
fuse-truncate-on-spontaneous-size-change.patch
fuse-fix-page-invalidation.patch
fuse-set-i_nlink-to-sane-value-after-mount.patch
fuse-refresh-stale-attributes-in-fuse_permission.patch
fuse-fix-permission-checking-on-sticky-directories.patch
fuse-fix-permission-checking-on-sticky-directories-fix.patch
fuse-cleanup-in-release.patch
fuse-no-abort-on-interrupt.patch
fuse-no-enoent-from-fuse-device-read.patch
exec-remove-unnecessary-check-for-mnt_noexec.patch
fuse-fix-setting-i_mode-bits.patch
fuse-clean-up-execute-permission-checking.patch
clean-out-unused-code-in-dentry-pruning.patch
uml-remove-unnecessary-hostfs_getattr.patch
fix-warnings-in-revoked_inodec.patch
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