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>
---
 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);
-- 
1.9.1

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