> On Dec 15, 2022, at 10:08 AM, Thomas Schmitt <scdbac...@gmx.net> wrote:
>
> Hi,
>
> On Wed, 14 Dec 2022 18:55:04 +0000 Lidong Chen <lidong.c...@oracle.com> wrote:
>> Added a check for the SP entry data boundary before reading it.
>>
>> Signed-off-by: Lidong Chen <lidong.c...@oracle.com>
>> ---
>> grub-core/fs/iso9660.c | 16 ++++++++++++++--
>> 1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/grub-core/fs/iso9660.c b/grub-core/fs/iso9660.c
>> index 9170fa820..67aa8451c 100644
>> --- a/grub-core/fs/iso9660.c
>> +++ b/grub-core/fs/iso9660.c
>> @@ -408,6 +408,9 @@ set_rockridge (struct grub_iso9660_data *data)
>> if (!sua_size)
>> return GRUB_ERR_NONE;
>>
>> + if (sua_size < GRUB_ISO9660_SUSP_HEADER_SZ)
>
> As mentioned in my review of patch [2/4], GRUB_ISO9660_SUSP_HEADER_SZ should
> be defined as 4, rather than as 5. Else entry RE could trigger this error:
>
>> + return grub_error (GRUB_ERR_BAD_FS, "invalid rock ridge entry size");
>> +
>> sua = grub_malloc (sua_size);
>> if (! sua)
>> return grub_errno;
>> @@ -434,8 +437,17 @@ set_rockridge (struct grub_iso9660_data *data)
>> rootnode.have_symlink = 0;
>> rootnode.dirents[0] = data->voldesc.rootdir;
>>
>> - /* The 2nd data byte stored how many bytes are skipped every time
>> - to get to the SUA (System Usage Area). */
>> + /*
>> + * The 2nd data byte stored how many bytes are skipped every time
>> + * to get to the SUA (System Usage Area).
>> + */
>> + if (sua_size < GRUB_ISO9660_SUSP_HEADER_SZ + 2 ||
>> + entry->len < GRUB_ISO9660_SUSP_HEADER_SZ + 2)
>
> This interprets an SP entry, which is specified to have 7 bytes.
> So if GRUB_ISO9660_SUSP_HEADER_SZ gets corrected to 4, then the size demand
> will have to be (GRUB_ISO9660_SUSP_HEADER_SZ + 3).
>
> Like with the NM interpretation i would rather prefer a plain "7", maybe with
> a comment which says that this is the fixed size of SP (version 1).
>
>
>> + {
>> + grub_free (sua);
>> + return grub_error (GRUB_ERR_BAD_FS, "corrupted rock ridge entry");
>> + }
>> +
>> data->susp_skip = entry->data[2];
>> entry = (struct grub_iso9660_susp_entry *) ((char *) entry +
>> entry->len);
>>
>> --
>> 2.35.1
>>
>
> Reviewed-by: Thomas Schmitt <scdbac...@gmx.net>
>
> But the expression (GRUB_ISO9660_SUSP_HEADER_SZ + 2) will need correction if
> my wish for
> #define GRUB_ISO9660_SUSP_HEADER_SZ 4
> gets fulfilled. As said, i'd prefer a plain "7".
>
Ok, I will change it to a plain ‘7’ and add a comment for it.
Thanks,
Lidong
>
> Have a nice day :)
>
> Thomas
>
_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel
