os: fix readdir_r buffer size

The buffer needs to be big or else we're walk all over the stack.

Backport: dumpling, cuttlefish, bobtail
Signed-off-by: Sage Weil <sage@inktank.com>
(cherry picked from commit 2df66d9fa214e90eb5141df4d5755b57e8ba9413)

Conflicts:

	src/os/BtrfsFileStoreBackend.cc

diff --git a/src/os/FileStore.cc b/src/os/FileStore.cc
index 5bd581f6254fec61729fce512c8e68063219e45b..9de73eca8b5270df1d41944a2b1fa428f1005768 100644 (file)
--- a/src/os/FileStore.cc
+++ b/src/os/FileStore.cc
@@ -1483,8 +1483,9 @@ int FileStore::mount()
       goto close_basedir_fd;
     }
 
+    char dbuf[offsetof(struct dirent, d_name) + PATH_MAX + 1];
     struct dirent *de;
-    while (::readdir_r(dir, (struct dirent *)buf, &de) == 0) {
+    while (::readdir_r(dir, (struct dirent *)dbuf, &de) == 0) {
       if (!de)
        break;
       long long unsigned c;
@@ -4428,8 +4429,9 @@ int FileStore::list_collections(vector<coll_t>& ls)
     return r;
   }
 
-  struct dirent sde, *de;
-  while ((r = ::readdir_r(dir, &sde, &de)) == 0) {
+  char buf[offsetof(struct dirent, d_name) + PATH_MAX + 1];
+  struct dirent *de;
+  while ((r = ::readdir_r(dir, (struct dirent *)&buf, &de)) == 0) {
     if (!de)
       break;
     if (de->d_type == DT_UNKNOWN) {