diff options
| -rw-r--r-- | hw/9pfs/9p.c | 12 | ||||
| -rw-r--r-- | hw/9pfs/9p.h | 11 |
2 files changed, 23 insertions, 0 deletions
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index b0e445d..c63f549 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -1363,8 +1363,20 @@ static void coroutine_fn v9fs_version(void *opaque) s->proto_version = V9FS_PROTO_2000L; } else { v9fs_string_sprintf(&version, "unknown"); + /* skip min. msize check, reporting invalid version has priority */ + goto marshal; } + if (s->msize < P9_MIN_MSIZE) { + err = -EMSGSIZE; + error_report( + "9pfs: Client requested msize < minimum msize (" + stringify(P9_MIN_MSIZE) ") supported by this server." + ); + goto out; + } + +marshal: err = pdu_marshal(pdu, offset, "ds", s->msize, &version); if (err < 0) { goto out; diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h index 8d07a0b..b8f72a3 100644 --- a/hw/9pfs/9p.h +++ b/hw/9pfs/9p.h @@ -100,6 +100,17 @@ typedef enum P9ProtoVersion { V9FS_PROTO_2000L = 0x02, } P9ProtoVersion; +/** + * @brief Minimum message size supported by this 9pfs server. + * + * A client establishes a session by sending a Tversion request along with a + * 'msize' parameter which suggests the server a maximum message size ever to be + * used for communication (for both requests and replies) between client and + * server during that session. If client suggests a 'msize' smaller than this + * value then session is denied by server with an error response. + */ +#define P9_MIN_MSIZE 4096 + #define P9_NOTAG UINT16_MAX #define P9_NOFID UINT32_MAX #define P9_MAXWELEM 16 |