Two different implementations were in use for reading features files. One for reading a single file and another for reading a single file after walking a directory. This patch creates a single function that is used in both cases.
Signed-off-by: Tyler Hicks <[email protected]> --- libraries/libapparmor/src/features.c | 114 +++++++++++++++++++++-------------- 1 file changed, 68 insertions(+), 46 deletions(-) diff --git a/libraries/libapparmor/src/features.c b/libraries/libapparmor/src/features.c index e7bf745..f913e91 100644 --- a/libraries/libapparmor/src/features.c +++ b/libraries/libapparmor/src/features.c @@ -80,6 +80,69 @@ static int features_snprintf(struct features_struct *fst, const char *fmt, ...) return 0; } +/* load_features_file - opens and reads a file into @buffer and then NUL-terminates @buffer + * @dirfd: a directory file descriptory or AT_FDCWD (see openat(2)) + * @path: name of the file + * @buffer: the buffer to read the features file into (will be NUL-terminated on success) + * @size: the size of @buffer + * + * Returns: The number of bytes copied into @buffer on success (not counting + * the NUL-terminator), else -1 and errno is set. Note that @size must be + * larger than the size of the file or -1 will be returned with errno set to + * ENOBUFS indicating that @buffer was not large enough to contain all of the + * file contents. + */ +static int load_features_file(int dirfd, const char *path, + char *buffer, size_t size) +{ + autoclose int file = -1; + char *pos = buffer; + ssize_t len; + + file = openat(dirfd, path, O_RDONLY); + if (file < 0) { + PDEBUG("Could not open '%s'\n", path); + return -1; + } + PDEBUG("Opened features \"%s\"\n", path); + + if (!size) { + errno = ENOBUFS; + return -1; + } + + /* Save room for a NUL-terminator at the end of @buffer */ + size--; + + do { + len = read(file, pos, size); + if (len > 0) { + size -= len; + pos += len; + } + } while (len > 0 && size); + + /** + * Possible error conditions: + * - len == -1: read failed and errno is already set so return -1 + * - len > 0: read() never returned 0 (EOF) meaning that @buffer was + * too small to contain all of the file contents so set + * errno to ENOBUFS and return -1 + */ + if (len) { + if (len > 0) + errno = ENOBUFS; + + PDEBUG("Error reading features file '%s': %m\n", path); + return -1; + } + + /* NUL-terminate @buffer */ + *pos = 0; + + return pos - buffer; +} + static int features_dir_cb(int dirfd, const char *name, struct stat *st, void *data) { @@ -93,34 +156,14 @@ static int features_dir_cb(int dirfd, const char *name, struct stat *st, return -1; if (S_ISREG(st->st_mode)) { - autoclose int file = -1; int len; int remaining = fst->size - (fst->pos - fst->buffer); - file = openat(dirfd, name, O_RDONLY); - if (file == -1) { - PDEBUG("Could not open '%s'", name); - return -1; - } - PDEBUG("Opened features \"%s\"\n", name); - if (st->st_size > remaining) { - PDEBUG("Feature buffer full."); - errno = ENOBUFS; + len = load_features_file(dirfd, name, fst->pos, remaining); + if (len < 0) return -1; - } - do { - len = read(file, fst->pos, remaining); - if (len > 0) { - remaining -= len; - fst->pos += len; - *fst->pos = 0; - } - } while (len > 0); - if (len < 0) { - PDEBUG("Error reading feature file '%s'\n", name); - return -1; - } + fst->pos += len; } else if (S_ISDIR(st->st_mode)) { if (_aa_dirat_for_each(dirfd, name, fst, features_dir_cb)) return -1; @@ -145,27 +188,6 @@ static int handle_features_dir(const char *filename, char *buffer, int size, return 0; } -static int load_features_file(const char *name, char *buffer, size_t size) -{ - autofclose FILE *f = NULL; - size_t end; - - f = fopen(name, "r"); - if (!f) - return -1; - - errno = 0; - end = fread(buffer, 1, size - 1, f); - if (ferror(f)) { - if (!errno) - errno = EIO; - return -1; - } - buffer[end] = 0; - - return 0; -} - static bool islbrace(int c) { return c == '{'; @@ -362,8 +384,8 @@ int aa_features_new(aa_features **features, const char *path) retval = S_ISDIR(stat_file.st_mode) ? handle_features_dir(path, f->string, STRING_SIZE, f->string) : - load_features_file(path, f->string, STRING_SIZE); - if (retval) { + load_features_file(AT_FDCWD, path, f->string, STRING_SIZE); + if (retval == -1) { int save = errno; aa_features_unref(f); -- 2.1.4 -- AppArmor mailing list [email protected] Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/apparmor
