grub2/0363-fs-iso9660-Fix-invalid-free.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Michael Chang <mchang@suse.com>
Date: Fri, 31 May 2024 15:14:42 +0800
Subject: [PATCH] fs/iso9660: Fix invalid free

The ctx->filename can point to either a string literal or a dynamically
allocated string. The ctx->filename_alloc field is used to indicate the
type of allocation.

An issue has been identified where ctx->filename is reassigned to
a string literal in susp_iterate_dir() but ctx->filename_alloc is not
correctly handled. This oversight causes a memory leak and an invalid
free operation later.

The fix involves checking ctx->filename_alloc, freeing the allocated
string if necessary and clearing ctx->filename_alloc for string literals.

Reported-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Chang <mchang@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/fs/iso9660.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/grub-core/fs/iso9660.c b/grub-core/fs/iso9660.c
index 82cf1a271..7a59a65a5 100644
--- a/grub-core/fs/iso9660.c
+++ b/grub-core/fs/iso9660.c
@@ -568,9 +568,19 @@ susp_iterate_dir (struct grub_iso9660_susp_entry *entry,
 	 filename type is stored.  */
       /* FIXME: Fix this slightly improper cast.  */
       if (entry->data[0] & GRUB_ISO9660_RR_DOT)
-	ctx->filename = (char *) ".";
+	{
+	  if (ctx->filename_alloc)
+	    grub_free (ctx->filename);
+	  ctx->filename_alloc = 0;
+	  ctx->filename = (char *) ".";
+	}
       else if (entry->data[0] & GRUB_ISO9660_RR_DOTDOT)
-	ctx->filename = (char *) "..";
+	{
+	  if (ctx->filename_alloc)
+	    grub_free (ctx->filename);
+	  ctx->filename_alloc = 0;
+	  ctx->filename = (char *) "..";
+	}
       else if (entry->len >= 5)
 	{
 	  grub_size_t off = 0, csize = 1;