efivarfs: Fix memory leak of efivarfs_fs_info in fs_context error paths

When processing mount options, efivarfs allocates efivarfs_fs_info (sfi)
early in fs_context initialization. However, sfi is associated with the
superblock and typically freed when the superblock is destroyed. If the
fs_context is released (final put) before fill_super is called—such as
on error paths or during reconfiguration—the sfi structure would leak,
as ownership never transfers to the superblock.

Implement the .free callback in efivarfs_context_ops to ensure any
allocated sfi is properly freed if the fs_context is torn down before
fill_super, preventing this memory leak.

Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Fixes: 5329aa5101f73c ("efivarfs: Add uid/gid mount options")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index c900d98bf49459cf37bfdf1374e6002a7544b521..284d6dbba2ece827f80e8f6f191437c681694b01 100644 (file)
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -390,10 +390,16 @@ static int efivarfs_reconfigure(struct fs_context *fc)
        return 0;
 }
 
+static void efivarfs_free(struct fs_context *fc)
+{
+       kfree(fc->s_fs_info);
+}
+
 static const struct fs_context_operations efivarfs_context_ops = {
        .get_tree       = efivarfs_get_tree,
        .parse_param    = efivarfs_parse_param,
        .reconfigure    = efivarfs_reconfigure,
+       .free           = efivarfs_free,
 };
 
 static int efivarfs_check_missing(efi_char16_t *name16, efi_guid_t vendor,