s3:libsmb: let cli_read_max_bufsize() return the max number of possible bytes

s3:libsmb: let cli_read_max_bufsize() return the max number of possible bytes

We now return what's possible on the wire.

Which is 0xFFFF if CAP_LARGE_READX is given by the server
or 0xFFFFFF - data_offset if CIFS_UNIX_LARGE_READ_CAP
is available (without signing/sealing). Otherwise we return
max_xmit - data_offset.

metze

Signed-off-by: Jeremy Allison <jra@samba.org>

diff --git a/source3/libsmb/clireadwrite.c b/source3/libsmb/clireadwrite.c
index cd732529e94bb82caba7e92a4ba467ffa32d7fb1..d1c58f7c2a2b059873cd062f3b685c2ae365a9bd 100644 (file)
--- a/source3/libsmb/clireadwrite.c
+++ b/source3/libsmb/clireadwrite.c
@@ -28,27 +28,42 @@
 ****************************************************************************/
 static size_t cli_read_max_bufsize(struct cli_state *cli)
 {
-       size_t data_offset = smb_size - 4;
-       size_t wct = 12;
-
-       size_t useable_space;
-
-       if (!client_is_signing_on(cli) && !cli_encryption_on(cli)
-           && (cli->server_posix_capabilities & CIFS_UNIX_LARGE_READ_CAP)) {
-               return CLI_SAMBA_MAX_POSIX_LARGE_READX_SIZE;
-       }
-       if (cli_state_capabilities(cli) & CAP_LARGE_READX) {
-               return cli->is_samba
-                       ? CLI_SAMBA_MAX_LARGE_READX_SIZE
-                       : CLI_WINDOWS_MAX_LARGE_READX_SIZE;
-       }
+       uint8_t wct = 12;
+       uint32_t min_space;
+       uint32_t data_offset;
+       uint32_t useable_space = 0;
 
+       data_offset = HDR_VWV;
        data_offset += wct * sizeof(uint16_t);
+       data_offset += sizeof(uint16_t); /* byte count */
        data_offset += 1; /* pad */
 
-       useable_space = cli_state_available_size(cli, data_offset);
+       min_space = cli_state_available_size(cli, data_offset);
+
+       if (cli->server_posix_capabilities & CIFS_UNIX_LARGE_READ_CAP) {
+               useable_space = 0xFFFFFF - data_offset;
+
+               if (client_is_signing_on(cli)) {
+                       return min_space;
+               }
+
+               if (cli_encryption_on(cli)) {
+                       return min_space;
+               }
+
+               return useable_space;
+       } else if (cli_state_capabilities(cli) & CAP_LARGE_READX) {
+               /*
+                * Note: CAP_LARGE_READX also works with signing
+                */
+               useable_space = 0x1FFFF - data_offset;
+
+               useable_space = MIN(useable_space, UINT16_MAX);
+
+               return useable_space;
+       }
 
-       return useable_space;
+       return min_space;
 }
 
 /****************************************************************************