linux-kernel - [PATCH v3] ima: silence measurement list hexdump during kexec

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Date:   Mon, 27 Dec 2021 11:52:03 -0300
From:   Bruno Meneguele <bmeneg@...hat.com>
To:     zohar@...ux.ibm.com
Cc:     linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bruno Meneguele <bmeneg@...hat.com>
Subject: [PATCH v3] ima: silence measurement list hexdump during kexec

The measurement list is being dumped during soft resets (kexec) through the
call to print_hex_dump(KERN_DEBUG, ...) without considering the DEBUG
compilation flag. With that, to avoid dumping this information to the system
log whenever a soft reset happens during boot process, since the default
console loglevel is generally set to 7 (debug) during boot, guard the call
to print_hex_dump() with #ifdef for the DEBUG cflag.

Signed-off-by: Bruno Meneguele <bmeneg@...hat.com>
---
Changelog:
- v2: guard call with #ifdef instead of using print_hex_dump_debug, which
  would not completely solve the case.
- v1: update commit log with more information.

 security/integrity/ima/ima_kexec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index f799cc278a9a..2d6db5fbda41 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -61,9 +61,11 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
 	}
 	memcpy(file.buf, &khdr, sizeof(khdr));
 
+#if defined(DEBUG)
 	print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE,
 			16, 1, file.buf,
 			file.count < 100 ? file.count : 100, true);
+#endif
 
 	*buffer_size = file.count;
 	*buffer = file.buf;
-- 
2.33.1