@@ -216,6 +216,11 @@ ssize_t pt_listxattr(FsContext *ctx, const char *path,
return name_size;
}
+static ssize_t flistxattrat(int dirfd, const char *path, char *list,
+ size_t size)
+{
+ return do_xattrat_op(XATTRAT_OP_LIST, dirfd, path, NULL, list, size, 0);
+}
/*
* Get the list and pass to each layer to find out whether
@@ -225,24 +230,37 @@ ssize_t v9fs_list_xattr(FsContext *ctx, const char *path,
void *value, size_t vsize)
{
ssize_t size = 0;
- char *buffer;
void *ovalue = value;
XattrOperations *xops;
char *orig_value, *orig_value_start;
ssize_t xattr_len, parsed_len = 0, attr_len;
+ char *dirpath, *name;
+ int dirfd;
/* Get the actual len */
- buffer = rpath(ctx, path);
- xattr_len = llistxattr(buffer, value, 0);
+ dirpath = g_path_get_dirname(path);
+ dirfd = local_opendir_nofollow(ctx, dirpath);
+ g_free(dirpath);
+ if (dirfd == -1) {
+ return -1;
+ }
+
+ name = g_path_get_basename(path);
+ xattr_len = flistxattrat(dirfd, name, value, 0);
if (xattr_len <= 0) {
- g_free(buffer);
+ g_free(name);
+ close_preserve_errno(dirfd);
return xattr_len;
}
/* Now fetch the xattr and find the actual size */
orig_value = g_malloc(xattr_len);
- xattr_len = llistxattr(buffer, orig_value, xattr_len);
- g_free(buffer);
+ xattr_len = flistxattrat(dirfd, name, orig_value, xattr_len);
+ g_free(name);
+ close_preserve_errno(dirfd);
+ if (xattr_len < 0) {
+ return -1;
+ }
/* store the orig pointer */
orig_value_start = orig_value;
The local_llistxattr() callback is vulnerable to symlink attacks because it calls llistxattr() which follows symbolic links in all path elements but the rightmost one. This patch converts local_llistxattr() to rely on opendir_nofollow() and flistxattrat_nofollow() instead. This partly fixes CVE-2016-9602. Signed-off-by: Greg Kurz <groug@kaod.org> --- hw/9pfs/9p-xattr.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-)