[PATCH AUTOSEL 5.3 02/71] ima: always return negative code for error

Sasha Levin
2019-10-01T16:39:28Z

From: Sascha Hauer <s.hauer@pengutronix.de>

[ Upstream commit f5e1040196dbfe14c77ce3dfe3b7b08d2d961e88 ]

integrity_kernel_read() returns the number of bytes read. If this is
a short read then this positive value is returned from
ima_calc_file_hash_atfm(). Currently this is only indirectly called from
ima_calc_file_hash() and this function only tests for the return value
being zero or nonzero and also doesn't forward the return value.
Nevertheless there's no point in returning a positive value as an error,
so translate a short read into -EINVAL.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/integrity/ima/ima_crypto.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index d4c7b8e1b083d..7532b062be594 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -268,8 +268,11 @@ static int ima_calc_file_hash_atfm(struct file *file,
rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
rc = integrity_kernel_read(file, offset, rbuf[active],
rbuf_len);
- if (rc != rbuf_len)
+ if (rc != rbuf_len) {
+ if (rc >= 0)
+ rc = -EINVAL;
goto out3;
+ }

if (rbuf[1] && offset) {
/* Using two buffers, and it is not the first
--
2.20.1