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lib: Fix sbi_ecall_register_extension to prevent extension IDs overlap

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The original code does not prevent the following scenarios:
> sbi_ecall_register_extension(ext1); /* extension id (70-80) */
> sbi_ecall_register_extension(ext2); /* extension id (50-100) */

Signed-off-by: Xiang Wang <merle@hardenedlinux.org>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
This commit is contained in:
Xiang Wang
2020-03-19 03:15:47 +00:00
committed by Anup Patel
parent 315a87710f
commit a0c88ddb31
1 changed files with 11 additions and 3 deletions
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14
lib/sbi/sbi_ecall.c
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@@ -40,11 +40,19 @@ struct sbi_ecall_extension *sbi_ecall_find_extension(unsigned long extid)
int sbi_ecall_register_extension(struct sbi_ecall_extension *ext)
{
struct sbi_ecall_extension *t;
if (!ext || (ext->extid_end < ext->extid_start) || !ext->handle)
return SBI_EINVAL;
if (sbi_ecall_find_extension(ext->extid_start) ||
sbi_ecall_find_extension(ext->extid_end))
return SBI_EINVAL;
sbi_list_for_each_entry(t, &ecall_exts_list, head) {
unsigned long start = t->extid_start;
unsigned long end = t->extid_end;
if (end < ext->extid_start || ext->extid_end < start)
/* no overlap */;
else
return SBI_EINVAL;
}
SBI_INIT_LIST_HEAD(&ext->head);
sbi_list_add_tail(&ext->head, &ecall_exts_list);