[PATCH 4.19 050/114] ima: fix freeing ongoing ahash_request

[Greg Kroah-Hartman]

From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>

[ Upstream commit 4ece3125f21b1d42b84896c5646dbf0e878464e1 ]

integrity_kernel_read() can fail in which case we forward to call
ahash_request_free() on a currently running request. We have to wait
for its completion before we can free the request.

This was observed by interrupting a "find / -type f -xdev -print0 | xargs -0
cat 1>/dev/null" with ctrl-c on an IMA enabled filesystem.

Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 security/integrity/ima/ima_crypto.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index b7822d2b79736..f63b4bd45d60e 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -274,6 +274,11 @@ static int ima_calc_file_hash_atfm(struct file *file,
 		if (rc != rbuf_len) {
 			if (rc >= 0)
 				rc = -EINVAL;
+			/*
+			 * Forward current rc, do not overwrite with return value
+			 * from ahash_wait()
+			 */
+			ahash_wait(ahash_rc, &wait);
 			goto out3;
 		}
 
-- 
2.20.1