[PATCH 3/5] migration/multifd: Replace assert() with error_setg() in recv paths

[Peter Xu <peterx@redhat.com>]

QPL and UADK multifd backends use assert() to validate wire-controlled
fields like per-page compressed lengths and packet size consistency.  These
asserts will stop working with released version of binaries, so may stop
working.

Replace all assert() calls in the receive path with proper error_setg() so
validation failures are reported gracefully rather than crashing or
silently ignored.

While at it, touch up an assert() in qatzip recv path too.

Cc: qemu-stable <qemu-stable@nongnu.org>
Cc: Fabiano Rosas <farosas@suse.de>
Cc: Yuan Liu <yuan1.liu@intel.com>
Cc: Yichen Wang <yichen.wang@bytedance.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/multifd-qatzip.c |  5 ++++-
 migration/multifd-qpl.c    | 24 ++++++++++++++++++++----
 migration/multifd-uadk.c   | 24 ++++++++++++++++++++----
 3 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/migration/multifd-qatzip.c b/migration/multifd-qatzip.c
index 7419e5dc0d..0262e81eac 100644
--- a/migration/multifd-qatzip.c
+++ b/migration/multifd-qatzip.c
@@ -348,7 +348,10 @@ static int qatzip_recv(MultiFDRecvParams *p, Error **errp)
 
     multifd_recv_zero_page_process(p);
     if (!p->normal_num) {
-        assert(in_size == 0);
+        if (in_size != 0) {
+            error_setg(errp, "multifd %u: expected empty packet", p->id);
+            return -1;
+        }
         return 0;
     }
 
diff --git a/migration/multifd-qpl.c b/migration/multifd-qpl.c
index 52902eb00c..3826e7f340 100644
--- a/migration/multifd-qpl.c
+++ b/migration/multifd-qpl.c
@@ -664,26 +664,42 @@ static int multifd_qpl_recv(MultiFDRecvParams *p, Error **errp)
     }
     multifd_recv_zero_page_process(p);
     if (!p->normal_num) {
-        assert(in_size == 0);
+        if (in_size != 0) {
+            error_setg(errp, "multifd %u: expected empty packet", p->id);
+            return -1;
+        }
         return 0;
     }
 
     /* read compressed page lengths */
     len = p->normal_num * sizeof(uint32_t);
-    assert(len < in_size);
+    if (len >= in_size) {
+        error_setg(errp, "multifd %u: header len %"PRIu32
+                   " >= packet size %"PRIu32, p->id, len, in_size);
+        return -1;
+    }
     ret = qio_channel_read_all(p->c, (void *) qpl->zlen, len, errp);
     if (ret != 0) {
         return ret;
     }
     for (int i = 0; i < p->normal_num; i++) {
         qpl->zlen[i] = be32_to_cpu(qpl->zlen[i]);
-        assert(qpl->zlen[i] <= multifd_ram_page_size());
+        if (qpl->zlen[i] > multifd_ram_page_size()) {
+            error_setg(errp, "multifd %u: page %d compressed len %"
+                       PRIu32" too large", p->id, i, qpl->zlen[i]);
+            return -1;
+        }
         zbuf_len += qpl->zlen[i];
         ramblock_recv_bitmap_set_offset(p->block, p->normal[i]);
     }
 
     /* read compressed pages */
-    assert(in_size == len + zbuf_len);
+    if (in_size != len + zbuf_len) {
+        error_setg(errp, "multifd %u: packet size %"PRIu32
+                   " != header %"PRIu32" + data %"PRIu32,
+                   p->id, in_size, len, zbuf_len);
+        return -1;
+    }
     ret = qio_channel_read_all(p->c, (void *) qpl->zbuf, zbuf_len, errp);
     if (ret != 0) {
         return ret;
diff --git a/migration/multifd-uadk.c b/migration/multifd-uadk.c
index fd7cd9b5e8..d373615ba8 100644
--- a/migration/multifd-uadk.c
+++ b/migration/multifd-uadk.c
@@ -245,12 +245,19 @@ static int multifd_uadk_recv(MultiFDRecvParams *p, Error **errp)
 
     multifd_recv_zero_page_process(p);
     if (!p->normal_num) {
-        assert(in_size == 0);
+        if (in_size != 0) {
+            error_setg(errp, "multifd %u: expected empty packet", p->id);
+            return -1;
+        }
         return 0;
     }
 
     /* read compressed data lengths */
-    assert(hdr_len < in_size);
+    if (hdr_len >= in_size) {
+        error_setg(errp, "multifd %u: header len %"PRIu32
+                   " >= packet size %"PRIu32, p->id, hdr_len, in_size);
+        return -1;
+    }
     ret = qio_channel_read_all(p->c, (void *) uadk_data->buf_hdr,
                                hdr_len, errp);
     if (ret != 0) {
@@ -259,12 +266,21 @@ static int multifd_uadk_recv(MultiFDRecvParams *p, Error **errp)
 
     for (int i = 0; i < p->normal_num; i++) {
         uadk_data->buf_hdr[i] = be32_to_cpu(uadk_data->buf_hdr[i]);
+        if (uadk_data->buf_hdr[i] > page_size) {
+            error_setg(errp, "multifd %u: page %d compressed len %"PRIu32
+                       " too large", p->id, i, uadk_data->buf_hdr[i]);
+            return -1;
+        }
         data_len += uadk_data->buf_hdr[i];
-        assert(uadk_data->buf_hdr[i] <= page_size);
     }
 
     /* read compressed data */
-    assert(in_size == hdr_len + data_len);
+    if (in_size != hdr_len + data_len) {
+        error_setg(errp, "multifd %u: packet size %"PRIu32
+                   " != header %"PRIu32" + data %"PRIu32,
+                   p->id, in_size, hdr_len, data_len);
+        return -1;
+    }
     ret = qio_channel_read_all(p->c, (void *)buf, data_len, errp);
     if (ret != 0) {
         return ret;
-- 
2.54.0