[PATCH AUTOSEL 5.4 017/134] scsi: target: compare full CHAP_A Algorithm strings

[Sasha Levin]

From: David Disseldorp <ddiss@xxxxxxx>

[ Upstream commit 9cef2a7955f2754257a7cddedec16edae7b587d0 ]

RFC 2307 states:

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

      CHAP_A=<A1,A2...>

   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 51ddca2033e0a..8fe9b12a07a4d 100644
--- a/drivers/target/iscsi/iscsi_target_auth.c
+++ b/drivers/target/iscsi/iscsi_target_auth.c
@@ -70,7 +70,7 @@ 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");
 			kfree(orig);
 			return CHAP_DIGEST_MD5;
-- 
2.20.1