[PATCH] ima: Fix a use after free in ima_read_modsig()

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

This code frees "hdr" and then dereferences it on the next line to get
the error code.

Fixes: 39b07096364a ("ima: Implement support for module-style appended signatures")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
 security/integrity/ima/ima_modsig.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_modsig.c b/security/integrity/ima/ima_modsig.c
index c412e31d1714..d106885cc495 100644
--- a/security/integrity/ima/ima_modsig.c
+++ b/security/integrity/ima/ima_modsig.c
@@ -91,8 +91,9 @@ int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
 
 	hdr->pkcs7_msg = pkcs7_parse_message(buf + buf_len, sig_len);
 	if (IS_ERR(hdr->pkcs7_msg)) {
+		rc = PTR_ERR(hdr->pkcs7_msg);
 		kfree(hdr);
-		return PTR_ERR(hdr->pkcs7_msg);
+		return rc;
 	}
 
 	memcpy(hdr->raw_pkcs7, buf + buf_len, sig_len);
-- 
2.20.1