iscsi-target: fix extract_param to handle buffer length corner case

commit 369653e4fb511928511b0ce81f41c812ff1f28b6 upstream.

extract_param() is called with max_length set to the total size of the
output buffer.  It's not safe to allow a parameter length equal to the
buffer size as the terminating null would be written one byte past the
end of the output buffer.

Signed-off-by: Eric Seppanen <eric@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c
index 7d85f88..3486d12 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_nego.c
+++ b/drivers/target/iscsi/iscsi_target_nego.c
@@ -89,7 +89,7 @@ int extract_param(
        if (len < 0)
                return -1;
 
-       if (len > max_length) {
+       if (len >= max_length) {
                pr_err("Length of input: %d exeeds max_length:"
                        " %d\n", len, max_length);
                return -1;