Make updating sections after section header string table order-independent Function write_dso updates the section header table: it adds, removes and updates sections. It does this in two phases: - it calculates the effect of changing sections on the following sections sh_offset (as well as on the section header table e_shoff) - it makes sure sh_offset is sh_addralign aligned (as well as that the section header table e_shoff is ELFCLASS-appropriately aligned). The first phase is independent of the order of the section header table, apart from this loop: ... for (j = dso->ehdr.e_shstrndx + 1; j < dso->ehdr.e_shnum; ++j) dso->shdr[j].sh_offset += len; ... It adds an increase of the size of the section header string table to sections 'after' the section header string table. But the after test here is implemented in terms of order in the section header table, which only works if if the section header table is sorted. Make the first phase order-independent by rewriting the after test in terms of sh_offset. 2019-06-25 Tom de Vries * dwz.c (write_dso): Make updating of sections after section header string table robust against unsorted section header table. --- dwz.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/dwz.c b/dwz.c index 9e39824..101b6e3 100644 --- a/dwz.c +++ b/dwz.c @@ -10405,8 +10405,10 @@ write_dso (DSO *dso, const char *file, struct stat *st) dso->shdr[dso->ehdr.e_shstrndx].sh_size += len; if (dso->shdr[dso->ehdr.e_shstrndx].sh_offset < min_shoff) min_shoff = dso->shdr[dso->ehdr.e_shstrndx].sh_offset; - for (j = dso->ehdr.e_shstrndx + 1; j < dso->ehdr.e_shnum; ++j) - dso->shdr[j].sh_offset += len; + for (j = 1; j < dso->ehdr.e_shnum; ++j) + if (dso->shdr[j].sh_offset + > dso->shdr[dso->ehdr.e_shstrndx].sh_offset) + dso->shdr[j].sh_offset += len; if (ehdr.e_shoff > dso->shdr[dso->ehdr.e_shstrndx].sh_offset) ehdr.e_shoff += len; shstrtabadd += len;