On Fri, Sep 16, 2016 at 7:38 AM, Stephen Smalley <s...@tycho.nsa.gov> wrote:
> On 09/16/2016 10:30 AM, Stephen Smalley wrote:
>> On 09/15/2016 07:13 PM, william.c.robe...@intel.com wrote:
>>> From: William Roberts <william.c.robe...@intel.com>
>>>
>>> patch 5e15a52aaa cleans up the process_file() but introduced
>>> a bug. If the binary file cannot be opened, always attempt
>>> to fall back to the textual file, this was not occurring.
>>>
>>> The logic should be:
>>> 1. Open the newest file based on base path + suffix vs
>>>    base_path + suffix + ".bin".
>>> 2. If anything fails, attempt base_path + suffix.
>>>
>>> In the case that the file_contexts was the newest file and
>>> used for processing fails, it will attempt the same failure
>>> recovery, which will fail. It was decided to keep it this
>>> was for simplicity.
>>
>> I don't like the approach.  What we want is:
>> - if .bin file exists and is not older, try to load it,
>> - if any of the above fails (i.e. .bin file does not exist, is older, or
>> cannot be loaded for any reason), then load the text file.
>>
>> We shouldn't try loading the text file twice.
>>
>> Also, attached is checkpatch output for your patch.  Please fix.
>
> Also, there is a further wrinkle: Android passes in file_contexts.bin as
> the SELABEL_OPT_PATH, so that is the base path.  Under the old logic
> (before your original clean up patch), we would open that file, detect
> that it is binary, and then load it.  Under the current logic, we'll
> open file_contexts.bin, then try to open file_contexts.bin.bin (which
> will fail), and then use the first one.

Not true, I don't try to open it, I try to stat it.

>
> Wondering if we just need to revert.

If you want to revert I have no problem with that, but I provided IMO
a valid fix.
Since I won't likely have a next version patch out till after you go
home today, I
would support reverting.

>
>>
>>>
>>> Signed-off-by: William Roberts <william.c.robe...@intel.com>
>>> ---
>>>  libselinux/src/label_file.c | 41 +++++++++++++++++++++++++++--------------
>>>  1 file changed, 27 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c
>>> index 9faecdb..0dee059 100644
>>> --- a/libselinux/src/label_file.c
>>> +++ b/libselinux/src/label_file.c
>>> @@ -447,7 +447,7 @@ static bool fcontext_is_binary(FILE *fp)
>>>  #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
>>>
>>>  static FILE *open_file(const char *path, const char *suffix,
>>> -                   char *save_path, size_t len, struct stat *sb)
>>> +                   char *save_path, size_t len, struct stat *sb, bool 
>>> force_text)
>>>  {
>>>      unsigned int i;
>>>      int rc;
>>> @@ -469,7 +469,11 @@ static FILE *open_file(const char *path, const char 
>>> *suffix,
>>>              return NULL;
>>>      }
>>>
>>> -    for (i = 0; i < ARRAY_SIZE(fdetails); i++) {
>>> +    size_t array_size = ARRAY_SIZE(fdetails);
>>> +    if (force_text)
>>> +            array_size--;
>>> +
>>> +    for (i = 0; i < array_size; i++) {
>>>
>>>              /* This handles the case if suffix is null */
>>>              path = rolling_append(stack_path, fdetails[i].suffix,
>>> @@ -515,24 +519,33 @@ static int process_file(const char *path, const char 
>>> *suffix,
>>>                        const char *prefix, struct selabel_digest *digest)
>>>  {
>>>      int rc;
>>> +    unsigned int i;
>>>      struct stat sb;
>>>      FILE *fp = NULL;
>>>      char found_path[PATH_MAX];
>>>
>>> -    fp = open_file(path, suffix, found_path, sizeof(found_path), &sb);
>>> -    if (fp == NULL)
>>> -            return -1;
>>> +    /*
>>> +     * first path open the newest modified file, if it fails, the second
>>> +     * pass falls through to the plain text file.
>>> +     */
>>> +    for(i=0; i < 2; i++) {
>>> +            fp = open_file(path, suffix, found_path, sizeof(found_path), 
>>> &sb,
>>> +                            i > 0);
>>> +            if (fp == NULL)
>>> +                    return -1;
>>>
>>> -    rc = fcontext_is_binary(fp) ?
>>> -                    load_mmap(fp, sb.st_size, rec, found_path) :
>>> -                    process_text_file(fp, prefix, rec, found_path);
>>> -    if (rc < 0)
>>> -            goto out;
>>> +            rc = fcontext_is_binary(fp) ?
>>> +                            load_mmap(fp, sb.st_size, rec, found_path) :
>>> +                            process_text_file(fp, prefix, rec, found_path);
>>> +            if (!rc)
>>> +                    rc = digest_add_specfile(digest, fp, NULL, sb.st_size, 
>>> found_path);
>>>
>>> -    rc = digest_add_specfile(digest, fp, NULL, sb.st_size, found_path);
>>> -out:
>>> -    fclose(fp);
>>> -    return rc;
>>> +            fclose(fp);
>>> +
>>> +            if(!rc)
>>> +                    return 0;
>>> +    }
>>> +    return -1;
>>>  }
>>>
>>>  static void closef(struct selabel_handle *rec);
>>>
>>
>>
>>
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>>
>
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-- 
Respectfully,

William C Roberts
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