From 112d963a0542b1280667e2eb2727a8946d9bcf8d Mon Sep 17 00:00:00 2001 From: Tobias Stoeckmann Date: Mon, 13 Mar 2017 08:14:42 +0100 Subject: [PATCH] journal: prevent integer overflow while validating header (#5569) It is possible to overflow uint64_t while validating the header of a journal file. To prevent this, the addition itself is checked to be within the limits of UINT64_MAX first. To keep this readable, I have introduced two stack variables which hold the converted values during validation. (cherry picked from commit 6f94e420e8355421fc31713a0df760d6b20473ac) --- src/journal/journal-file.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c index a6ccb67..14cb01a 100644 --- a/src/journal/journal-file.c +++ b/src/journal/journal-file.c @@ -546,6 +546,8 @@ static bool warn_wrong_flags(const JournalFile *f, bool compatible) { } static int journal_file_verify_header(JournalFile *f) { + uint64_t arena_size, header_size; + assert(f); assert(f->header); @@ -564,17 +566,21 @@ static int journal_file_verify_header(JournalFile *f) { if (f->header->state >= _STATE_MAX) return -EBADMSG; + header_size = le64toh(f->header->header_size); + /* The first addition was n_data, so check that we are at least this large */ - if (le64toh(f->header->header_size) < HEADER_SIZE_MIN) + if (header_size < HEADER_SIZE_MIN) return -EBADMSG; if (JOURNAL_HEADER_SEALED(f->header) && !JOURNAL_HEADER_CONTAINS(f->header, n_entry_arrays)) return -EBADMSG; - if ((le64toh(f->header->header_size) + le64toh(f->header->arena_size)) > (uint64_t) f->last_stat.st_size) + arena_size = le64toh(f->header->arena_size); + + if (UINT64_MAX - header_size < arena_size || header_size + arena_size > (uint64_t) f->last_stat.st_size) return -ENODATA; - if (le64toh(f->header->tail_object_offset) > (le64toh(f->header->header_size) + le64toh(f->header->arena_size))) + if (le64toh(f->header->tail_object_offset) > header_size + arena_size) return -ENODATA; if (!VALID64(le64toh(f->header->data_hash_table_offset)) || -- 2.9.3