1 files changed, 44 insertions, 64 deletions

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 1b885c156028..c75625c1efa3 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -10,6 +10,7 @@
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/xattr.h>
+#include <linux/posix_acl.h>
 #include "overlayfs.h"
 
 static int ovl_copy_up_truncate(struct dentry *dentry)
@@ -191,32 +192,44 @@ static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
         return err;
 }
 
-static bool ovl_is_private_xattr(const char *name)
+bool ovl_is_private_xattr(const char *name)
 {
-#define OVL_XATTR_PRE_NAME OVL_XATTR_PREFIX "."
-        return strncmp(name, OVL_XATTR_PRE_NAME,
-                       sizeof(OVL_XATTR_PRE_NAME) - 1) == 0;
+        return strncmp(name, OVL_XATTR_PREFIX,
+                       sizeof(OVL_XATTR_PREFIX) - 1) == 0;
 }
 
-int ovl_setxattr(struct dentry *dentry, struct inode *inode,
-                 const char *name, const void *value,
-                 size_t size, int flags)
+int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
+                  size_t size, int flags)
 {
         int err;
-        struct dentry *upperdentry;
+        struct path realpath;
+        enum ovl_path_type type = ovl_path_real(dentry, &realpath);
         const struct cred *old_cred;
 
         err = ovl_want_write(dentry);
         if (err)
                 goto out;
 
+        if (!value && !OVL_TYPE_UPPER(type)) {
+                err = vfs_getxattr(realpath.dentry, name, NULL, 0);
+                if (err < 0)
+                        goto out_drop_write;
+        }
+
         err = ovl_copy_up(dentry);
         if (err)
                 goto out_drop_write;
 
-        upperdentry = ovl_dentry_upper(dentry);
+        if (!OVL_TYPE_UPPER(type))
+                ovl_path_upper(dentry, &realpath);
+
         old_cred = ovl_override_creds(dentry->d_sb);
-        err = vfs_setxattr(upperdentry, name, value, size, flags);
+        if (value)
+                err = vfs_setxattr(realpath.dentry, name, value, size, flags);
+        else {
+                WARN_ON(flags != XATTR_REPLACE);
+                err = vfs_removexattr(realpath.dentry, name);
+        }
         revert_creds(old_cred);
 
 out_drop_write:
@@ -225,16 +238,13 @@ out:
         return err;
 }
 
-ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
-                     const char *name, void *value, size_t size)
+int ovl_xattr_get(struct dentry *dentry, const char *name,
+                  void *value, size_t size)
 {
         struct dentry *realdentry = ovl_dentry_real(dentry);
         ssize_t res;
         const struct cred *old_cred;
 
-        if (ovl_is_private_xattr(name))
-                return -ENODATA;
-
         old_cred = ovl_override_creds(dentry->d_sb);
         res = vfs_getxattr(realdentry, name, value, size);
         revert_creds(old_cred);
@@ -245,7 +255,8 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 {
         struct dentry *realdentry = ovl_dentry_real(dentry);
         ssize_t res;
-        int off;
+        size_t len;
+        char *s;
         const struct cred *old_cred;
 
         old_cred = ovl_override_creds(dentry->d_sb);
@@ -255,73 +266,39 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
                 return res;
 
         /* filter out private xattrs */
-        for (off = 0; off < res;) {
-                char *s = list + off;
-                size_t slen = strlen(s) + 1;
+        for (s = list, len = res; len;) {
+                size_t slen = strnlen(s, len) + 1;
 
-                BUG_ON(off + slen > res);
+                /* underlying fs providing us with an broken xattr list? */
+                if (WARN_ON(slen > len))
+                        return -EIO;
 
+                len -= slen;
                 if (ovl_is_private_xattr(s)) {
                         res -= slen;
-                        memmove(s, s + slen, res - off);
+                        memmove(s, s + slen, len);
                 } else {
-                        off += slen;
+                        s += slen;
                 }
         }
 
         return res;
 }
 
-int ovl_removexattr(struct dentry *dentry, const char *name)
-{
-        int err;
-        struct path realpath;
-        enum ovl_path_type type = ovl_path_real(dentry, &realpath);
-        const struct cred *old_cred;
-
-        err = ovl_want_write(dentry);
-        if (err)
-                goto out;
-
-        err = -ENODATA;
-        if (ovl_is_private_xattr(name))
-                goto out_drop_write;
-
-        if (!OVL_TYPE_UPPER(type)) {
-                err = vfs_getxattr(realpath.dentry, name, NULL, 0);
-                if (err < 0)
-                        goto out_drop_write;
-
-                err = ovl_copy_up(dentry);
-                if (err)
-                        goto out_drop_write;
-
-                ovl_path_upper(dentry, &realpath);
-        }
-
-        old_cred = ovl_override_creds(dentry->d_sb);
-        err = vfs_removexattr(realpath.dentry, name);
-        revert_creds(old_cred);
-out_drop_write:
-        ovl_drop_write(dentry);
-out:
-        return err;
-}
-
 struct posix_acl *ovl_get_acl(struct inode *inode, int type)
 {
         struct inode *realinode = ovl_inode_real(inode, NULL);
         const struct cred *old_cred;
         struct posix_acl *acl;
 
-        if (!IS_POSIXACL(realinode))
+        if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode))
                 return NULL;
 
         if (!realinode->i_op->get_acl)
                 return NULL;
 
         old_cred = ovl_override_creds(inode->i_sb);
-        acl = realinode->i_op->get_acl(realinode, type);
+        acl = get_acl(realinode, type);
         revert_creds(old_cred);
 
         return acl;
@@ -391,9 +368,9 @@ static const struct inode_operations ovl_file_inode_operations = {
         .permission     = ovl_permission,
         .getattr        = ovl_getattr,
         .setxattr       = generic_setxattr,
-        .getxattr       = ovl_getxattr,
+        .getxattr       = generic_getxattr,
         .listxattr      = ovl_listxattr,
-        .removexattr    = ovl_removexattr,
+        .removexattr    = generic_removexattr,
         .get_acl        = ovl_get_acl,
         .update_time    = ovl_update_time,
 };
@@ -404,9 +381,9 @@ static const struct inode_operations ovl_symlink_inode_operations = {
         .readlink       = ovl_readlink,
         .getattr        = ovl_getattr,
         .setxattr       = generic_setxattr,
-        .getxattr       = ovl_getxattr,
+        .getxattr       = generic_getxattr,
         .listxattr      = ovl_listxattr,
-        .removexattr    = ovl_removexattr,
+        .removexattr    = generic_removexattr,
         .update_time    = ovl_update_time,
 };
 
@@ -415,6 +392,9 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode)
         inode->i_ino = get_next_ino();
         inode->i_mode = mode;
         inode->i_flags |= S_NOCMTIME;
+#ifdef CONFIG_FS_POSIX_ACL
+        inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
+#endif
 
         mode &= S_IFMT;
         switch (mode) {