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net_sched: Use struct_size() and flex_array_size() helpers

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Make use of the struct_size() and flex_array_size() helpers instead of
an open-coded version, in order to avoid any potential type mistakes
or integer overflows that, in the worse scenario, could lead to heap
overflows.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20210928193107.GA262595@embeddedor
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Gustavo A. R. Silva 2021-09-28 14:31:07 -05:00 committed by Jakub Kicinski
parent ef91abfb20
commit 69508d4333
1 changed files with 4 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

7
net/sched/sch_api.c
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@ -507,20 +507,21 @@ static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt,
list_for_each_entry(stab, &qdisc_stab_list, list) { list_for_each_entry(stab, &qdisc_stab_list, list) {
if (memcmp(&stab->szopts, s, sizeof(*s))) if (memcmp(&stab->szopts, s, sizeof(*s)))
continue; continue;
if (tsize > 0 && memcmp(stab->data, tab, tsize * sizeof(u16))) if (tsize > 0 &&
memcmp(stab->data, tab, flex_array_size(stab, data, tsize)))
continue; continue;
stab->refcnt++; stab->refcnt++;
return stab; return stab;
} }
stab = kmalloc(sizeof(*stab) + tsize * sizeof(u16), GFP_KERNEL); stab = kmalloc(struct_size(stab, data, tsize), GFP_KERNEL);
if (!stab) if (!stab)
return ERR_PTR(-ENOMEM); return ERR_PTR(-ENOMEM);
stab->refcnt = 1; stab->refcnt = 1;
stab->szopts = *s; stab->szopts = *s;
if (tsize > 0) if (tsize > 0)
memcpy(stab->data, tab, tsize * sizeof(u16)); memcpy(stab->data, tab, flex_array_size(stab, data, tsize));
list_add_tail(&stab->list, &qdisc_stab_list); list_add_tail(&stab->list, &qdisc_stab_list);