When memset() is used before a release function such as free,
the compiler if allowed to optimize the memset away under
the as-if rules. This is normally ok, but in certain cases such
as passwords or security keys it is problematic.
Introduce a DPDK wrapper which uses the bzero_explicit function
or SecureZeroMemory on Windows.
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
---
lib/eal/common/eal_common_string_fns.c | 15 +++++++++++++++
lib/eal/include/rte_string_fns.h | 19 +++++++++++++++++++
lib/eal/version.map | 3 +++
3 files changed, 37 insertions(+)
diff --git a/lib/eal/common/eal_common_string_fns.c
b/lib/eal/common/eal_common_string_fns.c
index 9ca2045b18..af9efc1bf2 100644
--- a/lib/eal/common/eal_common_string_fns.c
+++ b/lib/eal/common/eal_common_string_fns.c
@@ -7,9 +7,14 @@
#include <stdio.h>
#include <stdlib.h>
+
#include <rte_string_fns.h>
#include <rte_errno.h>
+#ifdef RTE_EXEC_ENV_WINDOWS
+#include <rte_windows.h>
+#endif
+
/* split string into tokens */
int
rte_strsplit(char *string, int stringlen,
@@ -98,3 +103,13 @@ rte_str_to_size(const char *str)
}
return size;
}
+
+void
+rte_memzero_explicit(void *dst, size_t sz)
+{
+#ifdef RTE_EXEC_ENV_WINDOWS
+ SecureZeroMemory(dst, sz);
+#else
+ explicit_bzero(dst, sz);
+#endif
+}
diff --git a/lib/eal/include/rte_string_fns.h b/lib/eal/include/rte_string_fns.h
index 702bd81251..d83b346158 100644
--- a/lib/eal/include/rte_string_fns.h
+++ b/lib/eal/include/rte_string_fns.h
@@ -15,6 +15,7 @@
#include <stdio.h>
#include <string.h>
+#include <rte_atomic.h>
#include <rte_common.h>
#include <rte_compat.h>
@@ -149,6 +150,24 @@ rte_str_skip_leading_spaces(const char *src)
return p;
}
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Fill memory with zero's (e.g. sensitive keys).
+ * Normally using memset() is fine, but in cases where clearing out local data
+ * before going out of scope is required, use rte_memzero_explicit() instead
+ * to prevent the compiler from optimizing away the zeroing operation.
+ *
+ * @param dst
+ * target buffer
+ * @param sz
+ * number of bytes to fill
+ */
+__rte_experimental
+void
+rte_memzero_explicit(void *dst, size_t sz);
+
#ifdef __cplusplus
}
#endif
diff --git a/lib/eal/version.map b/lib/eal/version.map
index a20c713eb1..82a3e91c97 100644
--- a/lib/eal/version.map
+++ b/lib/eal/version.map
@@ -398,6 +398,9 @@ EXPERIMENTAL {
# added in 24.11
rte_bitset_to_str;
rte_lcore_var_alloc;
+
+ # added in 25.03
+ rte_memzero_explicit;
};
INTERNAL {
--
2.47.2
