[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH] cryptodisk: Fix Coverity use after free bug
From: |
Daniel Kiper |
Subject: |
Re: [PATCH] cryptodisk: Fix Coverity use after free bug |
Date: |
Thu, 13 Jan 2022 19:44:06 +0100 |
User-agent: |
NeoMutt/20170113 (1.7.2) |
On Sat, Jan 01, 2022 at 03:48:25PM -0600, Glenn Washburn wrote:
> The Coverity output is:
>
> *** CID 366905: Memory - illegal accesses (USE_AFTER_FREE)
> /grub-core/disk/cryptodisk.c: 1064 in grub_cryptodisk_scan_device_real()
> 1058 cleanup:
> 1059 if (askpass)
> 1060 {
> 1061 cargs->key_len = 0;
> 1062 grub_free (cargs->key_data);
> 1063 }
> >>> CID 366905: Memory - illegal accesses (USE_AFTER_FREE)
> >>> Using freed pointer "dev".
> 1064 return dev;
> 1065 }
> 1066
> 1067 #ifdef GRUB_UTIL
> 1068 #include <grub/util/misc.h>
> 1069 grub_err_t
>
> Here the 'dev' variable can point to a freed cryptodisk device if the
> function grub_cryptodisk_insert() fails. This can happen only on a OOM
> condition, but when this happens grub_cryptodisk_insert() calls grub_free on
> the passed device. Since grub_cryptodisk_scan_device_real() assumes that
> grub_cryptodisk_insert() is always successful, it will return the device,
> though the device was freed.
>
> Change grub_cryptodisk_insert() to not free the passed device on failure.
> Then on grub_cryptodisk_insert() failure, free the device pointer. This is
> done by going to the label 'error', which will call cryptodisk_close() to
> free the device and set the device pointer to NULL, so that a pointer to
> freed memory is not returned.
>
> Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Daniel