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 108a857ab9fc9a8403dc110557c04d0f9f2cd179..cbf7b792309ef95efc5ffcbb88c68c5f91637e0a 100644 (file)
--- a/src/os/FileStore.cc
+++ b/src/os/FileStore.cc
@@ -1510,8 +1510,9 @@ 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;
@@ -4380,8 +4381,9 @@ 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) {