Set pointer to NULL after ext2fs_free

ext2fs_free() does not set the ext2_filsys pointer to null so the
caller is responsible to setting it himself if it is needed.

This patch fixes some places where caller did not set ext2_filsys
pointer to NULL after ext2fs_free() which might result in use after
free.  Fix it.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
index 8035755..a1a3517 100644 (file)
--- a/lib/ext2fs/openfs.c
+++ b/lib/ext2fs/openfs.c
@@ -450,10 +450,11 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
 
        return 0;
 cleanup:
-       if (flags & EXT2_FLAG_NOFREE_ON_ERROR)
-               *ret_fs = fs;
-       else
+       if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
                ext2fs_free(fs);
+               fs = NULL;
+       }
+       *ret_fs = fs;
        return retval;
 }
 

diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index b0c4b5e..27f508e 100644 (file)
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c
@@ -209,6 +209,7 @@ errcode_t resize_fs(ext2_filsys fs, blk64_t *new_size, int flags,
        rfs->flags = flags;
 
        ext2fs_free(rfs->old_fs);
+       rfs->old_fs = NULL;
        if (rfs->itable_buf)
                ext2fs_free_mem(&rfs->itable_buf);
        if (rfs->reserve_blocks)
@@ -220,8 +221,10 @@ errcode_t resize_fs(ext2_filsys fs, blk64_t *new_size, int flags,
        return 0;
 
 errout:
-       if (rfs->new_fs)
+       if (rfs->new_fs) {
                ext2fs_free(rfs->new_fs);
+               rfs->new_fs = NULL;
+       }
        if (rfs->itable_buf)
                ext2fs_free_mem(&rfs->itable_buf);
        ext2fs_free_mem(&rfs);