[SSSD] [PATCH] failover: Protect against empty host names
Pavel Březina
pbrezina at redhat.com
Wed Jan 2 11:08:31 UTC 2013
On 01/02/2013 12:07 PM, Pavel Březina wrote:
> On 12/03/2012 04:11 PM, Pavel Březina wrote:
>> On 12/03/2012 03:02 PM, Michal Židek wrote:
>>> On 12/03/2012 01:35 PM, Pavel Březina wrote:
>>>> On 11/30/2012 01:32 PM, Michal Židek wrote:
>>>>> On 11/30/2012 11:35 AM, Pavel Březina wrote:
>>>>>> On 11/29/2012 05:08 PM, Michal Židek wrote:
>>>>>>> On 11/27/2012 03:18 PM, Pavel Březina wrote:
>>>>>>>> On 11/26/2012 02:40 PM, Michal Židek wrote:
>>>>>>>>> On 11/23/2012 10:11 AM, Pavel Březina wrote:
>>>>>>>>>> On 10/17/2012 04:01 PM, Michal Židek wrote:
>>>>>>>>>>> On 10/16/2012 11:36 AM, Pavel Březina wrote:
>>>>>>>>>>>> On 10/15/2012 12:30 PM, Michal Židek wrote:
>>>>>>>>>>>>> Added new parameter to split_on_separator that allows to skip
>>>>>>>>>>>>> empty values.
>>>>>>>>>>>>>
>>>>>>>>>>>>> https://fedorahosted.org/sssd/ticket/1484
>>>>>>>>>>>>>
>>>>>>>>>>>>> Patch is in attachment.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Michal
>>>>>>>>>>>>
>>>>>>>>>>>> Nack. See below.
>>>>>>>>>>>>
>>>>>>>>>>>>> --- a/src/util/util.c
>>>>>>>>>>>>> +++ b/src/util/util.c
>>>>>>>>>>>>> @@ -31,7 +31,8 @@
>>>>>>>>>>>>> * the separator is a string, and is case-sensitive.
>>>>>>>>>>>>> * optionally single values can be trimmed of of spaces and
>>>>>>>>>>>>> tabs */
>>>>>>>>>>>>> int split_on_separator(TALLOC_CTX *mem_ctx, const char *str,
>>>>>>>>>>>>> - const char sep, bool trim, char
>>>>>>>>>>>>> ***_list,
>>>>>>>>>>>>> int
>>>>>>>>>>>>> *size)
>>>>>>>>>>>>> + const char sep, bool trim, bool
>>>>>>>>>>>>> skip_empty,
>>>>>>>>>>>>> + char ***_list, int *size)
>>>>>>>>>>>>> {
>>>>>>>>>>>>> const char *t, *p, *n;
>>>>>>>>>>>>> size_t l, len;
>>>>>>>>>>>>> @@ -80,6 +81,11 @@ int split_on_separator(TALLOC_CTX *mem_ctx,
>>>>>>>>>>>>> const
>>>>>>>>>>>>> char *str,
>>>>>>>>>>>>> }
>>>>>>>>>>>>>
>>>>>>>>>>>>> if (len == 0) {
>>>>>>>>>>>>> + if (skip_empty) {
>>>>>>>>>>>>> + /* Move to next string and continue */
>>>>>>>>>>>>> + t = n;
>>>>>>>>>>>>> + continue;
>>>>>>>>>>>>> + }
>>>>>>>>>>>>
>>>>>>>>>>>> Move this^ condition before talloc_realloc.
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> I did not like the function at all, it seemed to be written for
>>>>>>>>>>> different purpose but slightly modified to fit our needs. I
>>>>>>>>>>> wrote a
>>>>>>>>>>> new
>>>>>>>>>>> version in this patch and added test for it.
>>>>>>>>>>>
>>>>>>>>>>> New patch attached.
>>>>>>>>>>>
>>>>>>>>>>> Michal
>>>>>>>>>>
>>>>>>>>>> Hi,
>>>>>>>>>> can you rebase it atop the current master please?
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Sure, here is the new patch.
>>>>>>>>>
>>>>>>>>> Thanks
>>>>>>>>> Michal
>>>>>>>>
>>>>>>>> Thanks.
>>>>>>>>
>>>>>>>> Nack.
>>>>>>>>
>>>>>>>> Test issues:
>>>>>>>>
>>>>>>>>> + {
>>>>>>>>> + ", ,,",
>>>>>>>>> + (const char*[]){NULL,},
>>>>>>>>> + true, true,
>>>>>>>>> + 0, 0
>>>>>>>>> + },
>>>>>>>>
>>>>>>>> What is the meaning of the comma after NULL?
>>>>>>>>
>>>>>>>
>>>>>>> It had no meaning. Deleted.
>>>>>>>
>>>>>>>>> + for (i = 0; str_ref = sts[a].expected_list[i], str_out =
>>>>>>>>> list[i]; i++) {
>>>>>>>>> + fail_unless(!strcmp(str_ref, str_out),
>>>>>>>>> + "Expected:%s Got:%s\n", str_ref,
>>>>>>>>> str_out);
>>>>>>>>> + }
>>>>>>>>
>>>>>>>> Please use strcmp() == 0.
>>>>>>>>
>>>>>>>> Function issues:
>>>>>>>>
>>>>>>>>> char **r;
>>>>>>>>
>>>>>>>> Please, choose a better name for this variable. Something that
>>>>>>>> explains
>>>>>>>> its meaning. Maybe 'reallocated_list'?
>>>>>>>
>>>>>>> Done.
>>>>>>>
>>>>>>>>
>>>>>>>>> /* Trim leading whitespace if needed */
>>>>>>>>> while (trim && isspace(*substr_begin) &&
>>>>>>>>> substr_begin < substr_end) {
>>>>>>>>> substr_begin++;
>>>>>>>>> substr_len--;
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> /* Trim trailing whitespace if needed */
>>>>>>>>> while (trim && substr_end - 1 > substr_begin &&
>>>>>>>>> isspace(*(substr_end-1))) {
>>>>>>>>> substr_end--;
>>>>>>>>> substr_len--;
>>>>>>>>> }
>>>>>>>>
>>>>>>>> Put the condition on one line. And separate trim from while please.
>>>>>>>> if (trim) {
>>>>>>>> while () // leading
>>>>>>>>
>>>>>>>> while () // trailing
>>>>>>>> }
>>>>>>>>
>>>>>>>>> if (!(skip_empty && substr_len == 0)) {
>>>>>>>>
>>>>>>>> if (!skip_empty || substr_len == 0) is more readable in my opinion.
>>>>>>>>
>>>>>>>
>>>>>>> Done.
>>>>>>>
>>>>>>>>> if (substr_len == 0) {
>>>>>>>>> list[num_strings] = talloc_strdup(list, "");
>>>>>>>> ^
>>>>>>>>> } else {
>>>>>>>>> list[num_strings] = talloc_strndup(list,
>>>>>>>>> substr_begin,
>>>>>>>>> substr_len);
>>>>>>>> ^
>>>>>>>>> }
>>>>>>>>
>>>>>>>> Indentation...
>>>>>>>
>>>>>>> Done.
>>>>>>>
>>>>>>>>
>>>>>>>>> talloc_free(list);
>>>>>>>>> return ENOMEM;
>>>>>>>>
>>>>>>>> Can you use "fail" pattern instead of calling the former each time
>>>>>>>> allocation fails?
>>>>>>>
>>>>>>> Label "done:" added.
>>>>>>>
>>>>>>>>
>>>>>>>> Otherwise it looks good. I like the function.
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> New patch attached.
>>>>>>>
>>>>>>> Thanks
>>>>>>> Michal
>>>>>>
>>>>>> Hi,
>>>>>> I have few more nitpicks.
>>>>>>
>>>>>> In tests:
>>>>>>> {
>>>>>>> NULL,
>>>>>>> NULL,
>>>>>>> false,false,
>>>>>> ^ missing comma :P
>>>>>>> 0, EINVAL
>>>>>>> },
>>>>>
>>>>> I can see only missing space :P
>>>>>
>>>>>>
>>>>>> Function:
>>>>>>> while (isspace(*substr_begin) &&
>>>>>>> substr_begin < substr_end) {
>>>>>>> substr_begin++;
>>>>>>> substr_len--;
>>>>>>> }
>>>>>>>
>>>>>>> /* Trim trailing whitespace */
>>>>>>> while (substr_end - 1 > substr_begin &&
>>>>>>> isspace(*(substr_end-1))) {
>>>>>>> substr_end--;
>>>>>>> substr_len--;
>>>>>>> }
>>>>>>
>>>>>> Can you put those conditions on one line? Both fit into 80 char limit
>>>>>> perfectly and separating them doesn't really help clarity.
>>>>>>
>>>>>>> reallocated_list = talloc_realloc(mem_ctx, list, char*,
>>>>>>> num_strings + 2);
>>>>>> ^ indentation :)
>>>>>> and
>>>>>>> list = talloc(mem_ctx, char *);
>>>>>>
>>>>>> Allocate first on NULL and then talloc_steal() it to mem_ctx. This
>>>>>> way
>>>>>> we can catch memory leak. (I know it's obvious there are not any at
>>>>>> the
>>>>>> moment, but still...)
>>>>>>
>>>>>> And last comment - since the function was completely rewritten, can
>>>>>> you
>>>>>> pick either ptr == NULL or !ptr so it is consistent?
>>>>>>
>>>>>> I'm sorry, I should have came with these earlier.
>>>>>>
>>>>>> Thanks.
>>>>>>
>>>>>
>>>>> New patch attached.
>>>>>
>>>>> Thanks
>>>>> Michal
>>>>
>>>> Hi,
>>>> we're almost there, but still nack :(
>>>>
>>>> tmp_ctx is always NULL this way, so it doesn't work as a talloc context
>>>> at all. You could just use:
>>>>
>>>> talloc_realloc(NULL, list, ...);
>>>> talloc_free(list);
>>>>
>>>> or initialize tmp_ctx with talloc_new(NULL).
>>>
>>> Yes, that is what I thought I did :-D . I see I didn't.
>>>
>>>>
>>>> But I like it better with tmp context after all, because you don't have
>>>> to use reallocated_list then and the code is more straightforward.
>>>>
>>>> So you can use:
>>>> TALLOC_CTX *tmp_ctx = NULL;
>>>>
>>>> tmp_ctx = talloc_new(NULL);
>>>> if (tmp_ctx == NULL) {...}
>>>>
>>>> ...
>>>> list = talloc_realloc(tmp_ctx, list, char*, num_strings + 2);
>>>> if (list == NULL) {
>>>> ret = ENOMEM;
>>>> goto done;
>>>> }
>>>> ...
>>>> done:
>>>> talloc_free(tmp_ctx)
>>>
>>> You are right, with the tmp context, the reallocated_list is not needed.
>>>
>>>
>>> New patch attached.
>>>
>>> Thanks
>>> Michal
>>
>> Hi,
>> I dared to amend your patch with following changes:
>>
>> - if (substr_len == 0) {
>> - list[num_strings] = talloc_strdup(list, "");
>> - } else {
>> - list[num_strings] = talloc_strndup(list, substr_begin,
>> - substr_len);
>> - }
>> + /* empty string is stored for substr_len == 0 */
>> + list[num_strings] = talloc_strndup(list, substr_begin,
>> substr_len);
>> if (list[num_strings] == NULL) {
>> ret = ENOMEM;
>> goto done;
>>
>> talloc_strndup(list, substr_begin, 0) == talloc_strdup(list, "")
>> so we don't need to branch here
>>
>> -107,7 +102,7 @@ int split_on_separator(TALLOC_CTX *mem_ctx, const
>> char *str,
>> /* No allocations were done, make space for the NULL */
>> list = talloc(tmp_ctx, char *);
>> if (list == NULL) {
>> - ret ENOMEM;
>> + ret = ENOMEM;
>> goto done;
>> }
>> }
>>
>> You've somehow managed to delete = which was present in the previous
>> iteration.
>>
>> I tried this patch with various weird ldap uris and it works splendidly.
>>
>> ACK from me
>
> Just a remainder. This patch has been waiting for some time.
s/remainder/reminder :-)
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