s3: libsmbclient: Fix cli_splice() fallback when reading less than a complete file.

We were always asking for SPLICE_BLOCK_SIZE even when the
remaining bytes we wanted were smaller than that. This works
when using cli_splice() on a complete file, as the cli_read()
terminated the read at the right place. We always have the
space to read SPLICE_BLOCK_SIZE bytes so this isn't an overflow.

Found by Bailey Berro <baileyberro@google.com>

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13527

Signed-off-by: Bailey Berro <baileyberro@google.com>
Reviewed-by: Jeremy Allison <jra@samba.org>
Reviewed-by: David Disseldorp <ddiss@samba.org>
Autobuild-User(master): David Disseldorp <ddiss@samba.org>
Autobuild-Date(master): Fri Jul 13 14:57:14 CEST 2018 on sn-devel-144

(cherry picked from commit c9656fd2977557ab20ec4e3d87c385a9b2f1bf43)

diff --git a/selftest/knownfail b/selftest/knownfail
index a3518b8b62bbd3b42356de69689bd78bcff63b61..ba16fd72290e61b2bc60797d749e0e0f51d21f17 100644 (file)
--- a/selftest/knownfail
+++ b/selftest/knownfail
@@ -16,8 +16,6 @@
 ^samba3.*rap.sam.*.useradd # Not provided by Samba 3
 ^samba3.*rap.sam.*.userdelete # Not provided by Samba 3
 ^samba3.libsmbclient.opendir # This requires a workgroup called 'WORKGROUP' and for netbios browse lists to have been registered
-^samba3.smbtorture_s3.plain\(fileserver\).CLI_SPLICE
-^samba3.smbtorture_s3.plain\(ad_dc_ntvfs\).CLI_SPLICE
 # see bug 8412
 ^samba3.smb2.rename.*.simple_nodelete
 ^samba3.smb2.rename.*.no_share_delete_no_delete_access

diff --git a/source3/libsmb/clireadwrite.c b/source3/libsmb/clireadwrite.c
index 00ee09ece89de74455a59af5c895a2cc5cb81a87..67870d8c40bc94881bd5a9f6456b3674d3f2e596 100644 (file)
--- a/source3/libsmb/clireadwrite.c
+++ b/source3/libsmb/clireadwrite.c
@@ -1462,8 +1462,10 @@ static NTSTATUS cli_splice_fallback(TALLOC_CTX *frame,
        *written = 0;
 
        while (remaining) {
+               size_t to_read = MIN(remaining, SPLICE_BLOCK_SIZE);
+
                status = cli_read(srccli, src_fnum,
-                                 (char *)buf, src_offset, SPLICE_BLOCK_SIZE,
+                                 (char *)buf, src_offset, to_read,
                                  &nread);
                if (!NT_STATUS_IS_OK(status)) {
                        return status;