Use directory xattrs for symlinks

[zfs.git] / module / zfs / zpl_xattr.c

diff --git a/module/zfs/zpl_xattr.c b/module/zfs/zpl_xattr.c
index 51c81ed..d79d35b 100644 (file)
--- a/module/zfs/zpl_xattr.c
+++ b/module/zfs/zpl_xattr.c
@@ -80,6 +80,7 @@
 #include <sys/zfs_vfsops.h>
 #include <sys/zfs_vnops.h>
 #include <sys/zfs_znode.h>
+#include <sys/zap.h>
 #include <sys/vfs.h>
 #include <sys/zpl.h>
 
@@ -91,11 +92,8 @@ typedef struct xattr_filldir {
 } xattr_filldir_t;
 
 static int
-zpl_xattr_filldir(void *arg, const char *name, int name_len,
-    loff_t offset, uint64_t objnum, unsigned int d_type)
+zpl_xattr_filldir(xattr_filldir_t *xf, const char *name, int name_len)
 {
-       xattr_filldir_t *xf = arg;
-
        if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
                if (!(ITOZSB(xf->inode)->z_flags & ZSB_XATTR))
                        return (0);
@@ -118,12 +116,46 @@ zpl_xattr_filldir(void *arg, const char *name, int name_len,
        return (0);
 }
 
+/*
+ * Read as many directory entry names as will fit in to the provided buffer,
+ * or when no buffer is provided calculate the required buffer size.
+ */
+int
+zpl_xattr_readdir(struct inode *dxip, xattr_filldir_t *xf)
+{
+       zap_cursor_t zc;
+       zap_attribute_t zap;
+       int error;
+
+       zap_cursor_init(&zc, ITOZSB(dxip)->z_os, ITOZ(dxip)->z_id);
+
+       while ((error = -zap_cursor_retrieve(&zc, &zap)) == 0) {
+
+               if (zap.za_integer_length != 8 || zap.za_num_integers != 1) {
+                       error = -ENXIO;
+                       break;
+               }
+
+               error = zpl_xattr_filldir(xf, zap.za_name, strlen(zap.za_name));
+               if (error)
+                       break;
+
+               zap_cursor_advance(&zc);
+       }
+
+       zap_cursor_fini(&zc);
+
+       if (error == -ENOENT)
+               error = 0;
+
+       return (error);
+}
+
 static ssize_t
 zpl_xattr_list_dir(xattr_filldir_t *xf, cred_t *cr)
 {
        struct inode *ip = xf->inode;
        struct inode *dxip = NULL;
-       loff_t pos = 3;  /* skip '.', '..', and '.zfs' entries. */
        int error;
 
        /* Lookup the xattr directory */
@@ -135,8 +167,7 @@ zpl_xattr_list_dir(xattr_filldir_t *xf, cred_t *cr)
                return (error);
        }
 
-       /* Fill provided buffer via zpl_zattr_filldir helper */
-       error = -zfs_readdir(dxip, (void *)xf, zpl_xattr_filldir, &pos, cr);
+       error = zpl_xattr_readdir(dxip, xf);
        iput(dxip);
 
        return (error);
@@ -162,8 +193,8 @@ zpl_xattr_list_sa(xattr_filldir_t *xf)
        while ((nvp = nvlist_next_nvpair(zp->z_xattr_cached, nvp)) != NULL) {
                ASSERT3U(nvpair_type(nvp), ==, DATA_TYPE_BYTE_ARRAY);
 
-               error = zpl_xattr_filldir((void *)xf, nvpair_name(nvp),
-                    strlen(nvpair_name(nvp)), 0, 0, 0);
+               error = zpl_xattr_filldir(xf, nvpair_name(nvp),
+                    strlen(nvpair_name(nvp)));
                if (error)
                        return (error);
        }
@@ -225,6 +256,11 @@ zpl_xattr_get_dir(struct inode *ip, const char *name, void *value,
                goto out;
        }
 
+       if (size < i_size_read(xip)) {
+               error = -ERANGE;
+               goto out;
+       }
+
        error = zpl_read_common(xip, value, size, 0, UIO_SYSSPACE, 0, cr);
 out:
        if (xip)
@@ -263,9 +299,12 @@ zpl_xattr_get_sa(struct inode *ip, const char *name, void *value, size_t size)
        if (!size)
                return (nv_size);
 
-       memcpy(value, nv_value, MIN(size, nv_size));
+       if (size < nv_size)
+               return (-ERANGE);
+
+       memcpy(value, nv_value, nv_size);
 
-       return (MIN(size, nv_size));
+       return (nv_size);
 }
 
 static int
@@ -280,7 +319,7 @@ __zpl_xattr_get(struct inode *ip, const char *name, void *value, size_t size,
 
        if (zsb->z_use_sa && zp->z_is_sa) {
                error = zpl_xattr_get_sa(ip, name, value, size);
-               if (error >= 0)
+               if (error != -ENOENT)
                        goto out;
        }
 
@@ -399,6 +438,10 @@ zpl_xattr_set_sa(struct inode *ip, const char *name, const void *value,
                if (error == -ENOENT)
                        error = zpl_xattr_set_dir(ip, name, NULL, 0, flags, cr);
        } else {
+               /* Do not allow SA xattrs in symlinks (issue #1648) */
+               if (S_ISLNK(ip->i_mode))
+                       return (-EMLINK);
+
                /* Limited to 32k to keep nvpair memory allocations small */
                if (size > DXATTR_MAX_ENTRY_SIZE)
                        return (-EFBIG);
@@ -622,7 +665,7 @@ __zpl_xattr_security_init(struct inode *ip, const struct xattr *xattrs,
                        break;
        }
 
-        return (error);
+       return (error);
 }
 
 int
@@ -638,26 +681,25 @@ int
 zpl_xattr_security_init(struct inode *ip, struct inode *dip,
     const struct qstr *qstr)
 {
-        int error;
-        size_t len;
-        void *value;
-        char *name;
-
-        error = zpl_security_inode_init_security(ip, dip, qstr,
-           &name, &value, &len);
-        if (error) {
-                if (error == -EOPNOTSUPP)
-                        return 0;
+       int error;
+       size_t len;
+       void *value;
+       char *name;
 
-                return (error);
-        }
+       error = zpl_security_inode_init_security(ip, dip, qstr,
+         &name, &value, &len);
+       if (error) {
+               if (error == -EOPNOTSUPP)
+                       return 0;
+               return (error);
+       }
 
        error = __zpl_xattr_security_set(ip, name, value, len, 0);
 
-        kfree(name);
-        kfree(value);
+       kfree(name);
+       kfree(value);
 
-        return (error);
+       return (error);
 }
 #endif /* HAVE_CALLBACK_SECURITY_INODE_INIT_SECURITY */
 
@@ -673,6 +715,7 @@ xattr_handler_t *zpl_xattr_handlers[] = {
        &zpl_xattr_user_handler,
 #ifdef HAVE_POSIX_ACLS
        &zpl_xattr_acl_access_handler,
-        &zpl_xattr_acl_default_handler,
+       &zpl_xattr_acl_default_handler,
 #endif /* HAVE_POSIX_ACLS */
+       NULL
 };