6 files changed, 39 insertions, 19 deletions

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 48eb881..906ea6c 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -15,7 +15,8 @@
 #include <linux/xattr.h>
 #include <linux/security.h>
 #include <linux/uaccess.h>
-#include <linux/sched.h>
+#include <linux/sched/signal.h>
+#include <linux/cred.h>
 #include <linux/namei.h>
 #include <linux/fdtable.h>
 #include <linux/ratelimit.h>
@@ -371,7 +372,8 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
 	ovl_path_upper(parent, &parentpath);
 	upperdir = parentpath.dentry;
 
-	err = vfs_getattr(&parentpath, &pstat);
+	err = vfs_getattr(&parentpath, &pstat,
+			  STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT);
 	if (err)
 		return err;
 
@@ -450,7 +452,8 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
 		}
 
 		ovl_path_lower(next, &lowerpath);
-		err = vfs_getattr(&lowerpath, &stat);
+		err = vfs_getattr(&lowerpath, &stat,
+				  STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
 		/* maybe truncate regular file. this has no effect on dirs */
 		if (flags & O_TRUNC)
 			stat.size = 0;
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 16e06dd..6515796 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -138,9 +138,10 @@ static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
 	return err;
 }
 
-static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
-			 struct kstat *stat)
+static int ovl_dir_getattr(const struct path *path, struct kstat *stat,
+			   u32 request_mask, unsigned int flags)
 {
+	struct dentry *dentry = path->dentry;
 	int err;
 	enum ovl_path_type type;
 	struct path realpath;
@@ -148,7 +149,7 @@ static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
 
 	type = ovl_path_real(dentry, &realpath);
 	old_cred = ovl_override_creds(dentry->d_sb);
-	err = vfs_getattr(&realpath, stat);
+	err = vfs_getattr(&realpath, stat, request_mask, flags);
 	revert_creds(old_cred);
 	if (err)
 		return err;
@@ -264,7 +265,8 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
 		goto out;
 
 	ovl_path_upper(dentry, &upperpath);
-	err = vfs_getattr(&upperpath, &stat);
+	err = vfs_getattr(&upperpath, &stat,
+			  STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
 	if (err)
 		goto out_unlock;
 
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 08643ac..f8fe6bf 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -9,6 +9,7 @@
 
 #include <linux/fs.h>
 #include <linux/slab.h>
+#include <linux/cred.h>
 #include <linux/xattr.h>
 #include <linux/posix_acl.h>
 #include "overlayfs.h"
@@ -56,16 +57,17 @@ out:
 	return err;
 }
 
-static int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
-			 struct kstat *stat)
+static int ovl_getattr(const struct path *path, struct kstat *stat,
+		       u32 request_mask, unsigned int flags)
 {
+	struct dentry *dentry = path->dentry;
 	struct path realpath;
 	const struct cred *old_cred;
 	int err;
 
 	ovl_path_real(dentry, &realpath);
 	old_cred = ovl_override_creds(dentry->d_sb);
-	err = vfs_getattr(&realpath, stat);
+	err = vfs_getattr(&realpath, stat, request_mask, flags);
 	revert_creds(old_cred);
 	return err;
 }
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 9ad48d9..b8b0778 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/fs.h>
+#include <linux/cred.h>
 #include <linux/namei.h>
 #include <linux/xattr.h>
 #include <linux/ratelimit.h>
@@ -154,29 +155,38 @@ out_err:
 static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d,
 			    struct dentry **ret)
 {
-	const char *s = d->name.name;
+	/* Counting down from the end, since the prefix can change */
+	size_t rem = d->name.len - 1;
 	struct dentry *dentry = NULL;
 	int err;
 
-	if (*s != '/')
+	if (d->name.name[0] != '/')
 		return ovl_lookup_single(base, d, d->name.name, d->name.len,
 					 0, "", ret);
 
-	while (*s++ == '/' && !IS_ERR_OR_NULL(base) && d_can_lookup(base)) {
+	while (!IS_ERR_OR_NULL(base) && d_can_lookup(base)) {
+		const char *s = d->name.name + d->name.len - rem;
 		const char *next = strchrnul(s, '/');
-		size_t slen = strlen(s);
+		size_t thislen = next - s;
+		bool end = !next[0];
 
-		if (WARN_ON(slen > d->name.len) ||
-		    WARN_ON(strcmp(d->name.name + d->name.len - slen, s)))
+		/* Verify we did not go off the rails */
+		if (WARN_ON(s[-1] != '/'))
 			return -EIO;
 
-		err = ovl_lookup_single(base, d, s, next - s,
-					d->name.len - slen, next, &base);
+		err = ovl_lookup_single(base, d, s, thislen,
+					d->name.len - rem, next, &base);
 		dput(dentry);
 		if (err)
 			return err;
 		dentry = base;
-		s = next;
+		if (end)
+			break;
+
+		rem -= thislen + 1;
+
+		if (WARN_ON(rem >= d->name.len))
+			return -EIO;
 	}
 	*ret = dentry;
 	return 0;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 7b21881..c9e70d3 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -7,6 +7,7 @@
  * the Free Software Foundation.
  */
 
+#include <uapi/linux/magic.h>
 #include <linux/fs.h>
 #include <linux/namei.h>
 #include <linux/xattr.h>
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 01157d6..1953986 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -10,7 +10,9 @@
 #include <linux/fs.h>
 #include <linux/mount.h>
 #include <linux/slab.h>
+#include <linux/cred.h>
 #include <linux/xattr.h>
+#include <linux/sched/signal.h>
 #include "overlayfs.h"
 #include "ovl_entry.h"