On 09/16/2016 03:37 PM, william.c.robe...@intel.com wrote:
> From: William Roberts <william.c.robe...@intel.com>
> 
> patch 5e15a52aaa cleans up the process_file() routine,
> 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 between base path + suffix and
>    base_path + suffix + ".bin"
> 2. If anything fails, attempt to load the oldest file.
> 
> The result, with a concrete example, would be:
> If file_contexts is the newest file, and it cannot be
> processed, the code will fall back to file_contexts.bin
> and vice versa.
> 
> Signed-off-by: William Roberts <william.c.robe...@intel.com>

Thanks, applied.

> ---
>  libselinux/src/label_file.c | 47 
> ++++++++++++++++++++++++++++++---------------
>  1 file changed, 32 insertions(+), 15 deletions(-)
> 
> diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c
> index 9faecdb..ff6bc94 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 open_oldest)
>  {
>       unsigned int i;
>       int rc;
> @@ -493,9 +493,15 @@ static FILE *open_file(const char *path, const char 
> *suffix,
>                * includes equality. This provides a precedence on
>                * secondary suffixes even when the timestamp is the
>                * same. Ie choose file_contexts.bin over file_contexts
> -              * even if the time stamp is the same.
> +              * even if the time stamp is the same. Invert this logic
> +              * on open_oldest set to true. The idea is that if the
> +              * newest file failed to process, we can attempt to
> +              * process the oldest. The logic here is subtle and depends
> +              * on the array ordering in fdetails for the case when time
> +              * stamps are the same.
>                */
> -             if (fdetails[i].sb.st_mtime >= found->sb.st_mtime) {
> +             if (open_oldest ^
> +                     (fdetails[i].sb.st_mtime >= found->sb.st_mtime)) {
>                       found = &fdetails[i];
>                       strcpy(save_path, path);
>               }
> @@ -515,24 +521,35 @@ 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;
> +     /*
> +      * On the first pass open the newest modified file. If it fails to
> +      * process, then the second pass shall open the oldest file. If both
> +      * passes fail, then it's a fatal error.
> +      */
> +     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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