https://bugs.kde.org/show_bug.cgi?id=496571
Bug ID: 496571
Summary: False positive for null key passed to
bpf_map_get_next_key syscall.
Classification: Developer tools
Product: valgrind
Version: 3.22.0
Platform: Ubuntu
OS: Linux
Status: REPORTED
Severity: minor
Priority: NOR
Component: memcheck
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
The BPF function bpf_map_get_next_key takes a null key parameter to get the
first key in a map. Valgrind should not warn of an invalid pointer in this
case.
Locally tested fix:
diff --git a/coregrind/m_syswrap/syswrap-linux.c
b/coregrind/m_syswrap/syswrap-linux.c
index 177712117..9be77992c 100644
--- a/coregrind/m_syswrap/syswrap-linux.c
+++ b/coregrind/m_syswrap/syswrap-linux.c
@@ -12993,7 +12993,10 @@ PRE(sys_bpf)
}
/* Get size of key for this map. */
if (bpf_map_get_sizes(attr->map_fd, &key_size, &value_size)) {
- PRE_MEM_READ("bpf(attr->key)", attr->key, key_size);
+ /* Key is null when getting first entry in map. */
+ if (attr->key) {
+ PRE_MEM_READ("bpf(attr->key)", attr->key, key_size);
+ }
PRE_MEM_WRITE("bpf(attr->next_key)", attr->next_key, key_size);
}
}
--
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