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

[ Upstream commit 5429c8de56f6b2bd8f537df3a1e04e67b9c04282 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/block/opal_proto.h b/block/opal_proto.h
index b486b3ec7dc41e95a203524400b06a1a5f5f610c..a50191bddbc269eded76e9dcd498128f883f425d 100644 (file)
--- a/block/opal_proto.h
+++ b/block/opal_proto.h
@@ -66,6 +66,7 @@ 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 0ac5a4f3f2261ccb07a1792775a422a908fb3092..00e4d23ac49e7b3f168e33830ac29af1590a3531 100644 (file)
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -895,16 +895,20 @@ 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;