From e40b83335bb33d9a2d1c06cc269875b3b3d6c539 Mon Sep 17 00:00:00 2001

From: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

Date: Wed, 6 Apr 2022 18:17:43 +0530

Subject: [PATCH 2/5] fs/f2fs: Do not copy file names that are too long

A corrupt f2fs file system might specify a name length which is greater

than the maximum name length supported by the GRUB f2fs driver.

We will allocate enough memory to store the overly long name, but there

are only F2FS_NAME_LEN bytes in the source, so we would read past the end

of the source.

While checking directory entries, do not copy a file name with an invalid

length.

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

Signed-off-by: Daniel Axtens <dja@axtens.net>

Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

---

 grub-core/fs/f2fs.c | 4 ++++

 1 file changed, 4 insertions(+)

diff --git a/grub-core/fs/f2fs.c b/grub-core/fs/f2fs.c

index 8898b235e..df6beb544 100644

--- a/grub-core/fs/f2fs.c

+++ b/grub-core/fs/f2fs.c

@@ -1003,6 +1003,10 @@ grub_f2fs_check_dentries (struct grub_f2fs_dir_iter_ctx *ctx)

       ftype = ctx->dentry[i].file_type;

       name_len = grub_le_to_cpu16 (ctx->dentry[i].name_len);

+

+      if (name_len >= F2FS_NAME_LEN)

+        return 0;

+

       filename = grub_malloc (name_len + 1);

       if (!filename)

         return 0;

-- 

2.33.5