[PATCH 4.9 115/171] scsi: target: compare full CHAP_A Algorithm strings

From: Greg Kroah-Hartman
Date: Thu Jan 02 2020 - 17:31:30 EST

From: David Disseldorp <ddiss@xxxxxxx>

[ Upstream commit 9cef2a7955f2754257a7cddedec16edae7b587d0 ]

RFC 2307 states:

For CHAP [RFC1994], in the first step, the initiator MUST send:


Where A1,A2... are proposed algorithms, in order of preference.
For the Algorithm, as stated in [RFC1994], one value is required to
be implemented:

5 (CHAP with MD5)

LIO currently checks for this value by only comparing a single byte in
the tokenized Algorithm string, which means that any value starting with
a '5' (e.g. "55") is interpreted as "CHAP with MD5". Fix this by
comparing the entire tokenized string.

Reviewed-by: Lee Duncan <lduncan@xxxxxxxx>
Reviewed-by: Mike Christie <mchristi@xxxxxxxxxx>
Signed-off-by: David Disseldorp <ddiss@xxxxxxx>
Link: https://lore.kernel.org/r/20190912095547.22427-2-ddiss@xxxxxxx
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/target/iscsi/iscsi_target_auth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c
index f0d97305575d..aa3f98994c7d 100644
--- a/drivers/target/iscsi/iscsi_target_auth.c
+++ b/drivers/target/iscsi/iscsi_target_auth.c
@@ -74,7 +74,7 @@ static int chap_check_algorithm(const char *a_str)
if (!token)
goto out;

- if (!strncmp(token, "5", 1)) {
+ if (!strcmp(token, "5")) {
pr_debug("Selected MD5 Algorithm\n");