[PATCH] ima: add check for khdr->buffer_size

[Yan Zhu]

When khdr->buffer_size > size, continuing to use ima_parse_buf
may cause memory access out of bounds.

Fixes: 94c3aac567a9 ("ima: on soft reboot, restore the measurement list")

Signed-off-by: Yan Zhu <zhuyan2015@xxxxxxx>
---
 security/integrity/ima/ima_template.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index e5d941f48..02a38b2ee 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -399,6 +399,12 @@ int ima_restore_measurement_list(loff_t size, void *buf)
 		return -EINVAL;
 	}
 
+	if (khdr->buffer_size > (u64)size) {
+		pr_err("hkdr->buffer_size(%llu) is larger then size(%lld)", khdr->buffer_size,
+			size);
+		return -EINVAL;
+	}
+
 	bitmap_zero(hdr_mask, HDR__LAST);
 	bitmap_set(hdr_mask, HDR_PCR, 1);
 	bitmap_set(hdr_mask, HDR_DIGEST, 1);
-- 
2.33.0