1 files changed, 16 insertions, 6 deletions

diff --git a/lib/nlattr.c b/lib/nlattr.c
index 8bf78b4b78f0..dfa55c873c13 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -15,7 +15,11 @@
 #include <linux/types.h>
 #include <net/netlink.h>
 
-/* for these data types attribute length must be exactly given size */
+/* For these data types, attribute length should be exactly the given
+ * size. However, to maintain compatibility with broken commands, if the
+ * attribute length does not match the expected size a warning is emitted
+ * to the user that the command is sending invalid data and needs to be fixed.
+ */
 static const u8 nla_attr_len[NLA_TYPE_MAX+1] = {
         [NLA_U8]        = sizeof(u8),
         [NLA_U16]       = sizeof(u16),
@@ -28,8 +32,16 @@ static const u8 nla_attr_len[NLA_TYPE_MAX+1] = {
 };
 
 static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {
+        [NLA_U8]        = sizeof(u8),
+        [NLA_U16]       = sizeof(u16),
+        [NLA_U32]       = sizeof(u32),
+        [NLA_U64]       = sizeof(u64),
         [NLA_MSECS]     = sizeof(u64),
         [NLA_NESTED]    = NLA_HDRLEN,
+        [NLA_S8]        = sizeof(s8),
+        [NLA_S16]       = sizeof(s16),
+        [NLA_S32]       = sizeof(s32),
+        [NLA_S64]       = sizeof(s64),
 };
 
 static int validate_nla_bitfield32(const struct nlattr *nla,
@@ -69,11 +81,9 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
 
         BUG_ON(pt->type > NLA_TYPE_MAX);
 
-        /* for data types NLA_U* and NLA_S* require exact length */
-        if (nla_attr_len[pt->type]) {
-                if (attrlen != nla_attr_len[pt->type])
-                        return -ERANGE;
-                return 0;
+        if (nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) {
+                pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n",
+                                    current->comm, type);
         }
 
         switch (pt->type) {