commit cabcb752d7ecc2d16e6cb630b3de0684b4f97ec5 Author: Nick Mathewson nickm@torproject.org Date: Mon Nov 20 10:10:13 2017 -0500

In storagedir, take more care with errno on empty or mislabeled file

Required for 24099 fix -- we won't be able to act based on errno unless we can trust it. --- src/common/storagedir.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/src/common/storagedir.c b/src/common/storagedir.c index 31933f64c..c471ea911 100644 --- a/src/common/storagedir.c +++ b/src/common/storagedir.c @@ -187,14 +187,19 @@ storage_dir_get_usage(storage_dir_t *d) return d->usage; }

-/** Mmap a specified file within <b>d</b>. */ +/** Mmap a specified file within <b>d</b>. + * + * On failure, return NULL and set errno as for tor_mmap_file(). */ tor_mmap_t * storage_dir_map(storage_dir_t *d, const char *fname) { char *path = NULL; tor_asprintf(&path, "%s/%s", d->directory, fname); tor_mmap_t *result = tor_mmap_file(path); + int errval = errno; tor_free(path); + if (result == NULL) + errno = errval; return result; }

@@ -364,6 +369,10 @@ storage_dir_save_labeled_to_file(storage_dir_t *d, * the data's size into *<b>sz_out</b>. On success, also return a tor_mmap_t * object whose contents should not be used -- it needs to be kept around, * though, for as long as <b>data_out</b> is going to be valid. + * + * On failure, set errno as for tor_mmap_file() if the file was missing or + * empty, and set errno to EINVAL if the file was not in the labeled + * format expected. */ tor_mmap_t * storage_dir_map_labeled(storage_dir_t *dir, @@ -373,13 +382,20 @@ storage_dir_map_labeled(storage_dir_t *dir, size_t *sz_out) { tor_mmap_t *m = storage_dir_map(dir, fname); - if (! m) + int errval; + if (! m) { + errval = errno; goto err; + } const char *nulp = memchr(m->data, '\0', m->size); - if (! nulp) + if (! nulp) { + errval = EINVAL; goto err; - if (labels_out && config_get_lines(m->data, labels_out, 0) < 0) + } + if (labels_out && config_get_lines(m->data, labels_out, 0) < 0) { + errval = EINVAL; goto err; + } size_t offset = nulp - m->data + 1; tor_assert(offset <= m->size); *data_out = (const uint8_t *)(m->data + offset); @@ -388,6 +404,7 @@ storage_dir_map_labeled(storage_dir_t *dir, return m; err: tor_munmap_file(m); + errno = errval; return NULL; }