[ovs-dev] [PATCH v2] dynamic-string: fix a crash in ds_clone()

[Sriharsha Basavapatna]

In netdev_offload_dpdk_flow_create() when an offload request fails,
dump_flow() is called to log a warning message. The 's_tnl' string
in flow_patterns gets initialized in vport_to_rte_tunnel() conditionally
via ds_put_format(). If it is not initialized, it crashes later in
dump_flow_attr()->ds_clone()->memcpy() while dereferencing this string.

To fix this, check if memory for the src string has been allocated,
before copying it to the dst string.

Fixes: fa44a4a3ff7b ("ovn-controller: Persist desired conntrack groups.")
Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna at broadcom.com>

---

v1->v2: fix ds_clone(); ds_cstr() not needed in callers.

---

 lib/dynamic-string.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/dynamic-string.c b/lib/dynamic-string.c
index 6f7b610a9..fd0127ed1 100644
--- a/lib/dynamic-string.c
+++ b/lib/dynamic-string.c
@@ -460,6 +460,10 @@ ds_chomp(struct ds *ds, int c)
 void
 ds_clone(struct ds *dst, struct ds *source)
 {
+    if (!source->allocated) {
+        ds_init(dst);
+        return;
+    }
     dst->length = source->length;
     dst->allocated = dst->length;
     dst->string = xmalloc(dst->allocated + 1);
-- 
2.30.0.349.g30b29f044a


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