block: sed-opal: handle empty atoms when parsing response

The SED Opal response parsing function response_parse() does not
handle the case of an empty atom in the response. This causes
the entry count to be too high and the response fails to be
parsed. Recognizing, but ignoring, empty atoms allows response
handling to succeed.

Signed-off-by: Greg Joyce <gjoyce@linux.ibm.com>
Link: https://lore.kernel.org/r/20240216210417.3526064-2-gjoyce@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/opal_proto.h b/block/opal_proto.h
index dec7ce3..d247a45 100644 (file)
--- a/block/opal_proto.h
+++ b/block/opal_proto.h
@@ -71,6 +71,7 @@ enum opal_response_token {
 #define SHORT_ATOM_BYTE  0xBF
 #define MEDIUM_ATOM_BYTE 0xDF
 #define LONG_ATOM_BYTE   0xE3
+#define EMPTY_ATOM_BYTE  0xFF
 
 #define OPAL_INVAL_PARAM 12
 #define OPAL_MANUFACTURED_INACTIVE 0x08

diff --git a/block/sed-opal.c b/block/sed-opal.c
index 3d9e9cd..fa4dba5 100644 (file)
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -1056,16 +1056,20 @@ static int response_parse(const u8 *buf, size_t length,
                        token_length = response_parse_medium(iter, pos);
                else if (pos[0] <= LONG_ATOM_BYTE) /* long atom */
                        token_length = response_parse_long(iter, pos);
+               else if (pos[0] == EMPTY_ATOM_BYTE) /* empty atom */
+                       token_length = 1;
                else /* TOKEN */
                        token_length = response_parse_token(iter, pos);
 
                if (token_length < 0)
                        return token_length;
 
+               if (pos[0] != EMPTY_ATOM_BYTE)
+                       num_entries++;
+
                pos += token_length;
                total -= token_length;
                iter++;
-               num_entries++;
        }
 
        resp->num = num_entries;