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create-diff-object: make kpatch_check_relocations() more precise 

Use rela_target_offset() to make the relocation bounds checking more
precise.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
This commit is contained in:
Josh Poimboeuf 2022-05-12 06:02:15 -07:00
parent f0e3da336c
commit 017015a725
1 changed files with 21 additions and 7 deletions
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28
kpatch-build/create-diff-object.c
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@ -2593,18 +2593,32 @@ static void kpatch_check_relocations(struct kpatch_elf *kelf)
{
struct rela *rela;
struct section *relasec;
Elf_Data *sdata;
long sec_size;
long sec_off;
list_for_each_entry(relasec, &kelf->sections, list) {
if (!is_rela_section(relasec))
continue;
list_for_each_entry(rela, &relasec->relas, list) {
if (rela->sym->sec) {
sdata = rela->sym->sec->data;
if ((long)rela->sym->sym.st_value + rela->addend > (long)sdata->d_size) {
ERROR("out-of-range relocation %s+%lx in %s", rela->sym->name,
rela->addend, relasec->name);
}
if (!rela->sym->sec)
continue;
sec_size = rela->sym->sec->data->d_size;
sec_off = (long)rela->sym->sym.st_value +
rela_target_offset(kelf, relasec, rela);
/*
* This check isn't perfect: we still allow relocations
* to the end of a section. There are real instances
* of that, including ORC entries, LOCKDEP=n
* zero-length '__key' passing, and the loop edge case
* described in kpatch_replace_sections_syms(). For
* now, just allow all such cases.
*/
if (sec_off < 0 || sec_off > sec_size) {
ERROR("%s+0x%x: out-of-range relocation %s+%lx",
relasec->base->name, rela->offset,
rela->sym->name, rela->addend);
}
}
}