| Message ID | 1474050736-8237-1-git-send-email-william.c.roberts@intel.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On 09/16/2016 02:32 PM, william.c.roberts@intel.com wrote: > From: William Roberts <william.c.roberts@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.roberts@intel.com> > --- > libselinux/src/label_file.c | 48 +++++++++++++++++++++++++++++++-------------- > 1 file changed, 33 insertions(+), 15 deletions(-) > > diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c > index 9faecdb..4f3700c 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 +493,17 @@ 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) > + || (open_oldest > + && fdetails[i].sb.st_mtime < found->sb.st_mtime)) { This can be simplified using ^ (xor). > found = &fdetails[i]; > strcpy(save_path, path); > } > @@ -515,24 +523,34 @@ 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, opens > + * pass opens the oldest file. If both passes fail, its a fatal error. it is > + */ > + 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); >
diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c index 9faecdb..4f3700c 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 +493,17 @@ 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) + || (open_oldest + && fdetails[i].sb.st_mtime < found->sb.st_mtime)) { found = &fdetails[i]; strcpy(save_path, path); } @@ -515,24 +523,34 @@ 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 opens the oldest file. If both passes fail, its 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);