net: print the data returned by SO_ERROR as a string if it is too short

The data returned by getsockopt SO_ERROR is an integer.  If the buffer
size specified by userspace is less than sizeof(int), the data written
by the kernel should not be interpreted as an integer.

* src/net.c (print_get_error): Print the buffer as a string if its
length is less than sizeof(int).

1 files changed, 6 insertions, 4 deletions

diff --git a/src/net.c b/src/net.c
index a6ff1d653..4a499cd72 100644
--- a/src/net.c
+++ b/src/net.c
@@ -691,14 +691,16 @@ print_get_ucred(struct tcb *const tcp, const kernel_ulong_t addr,
 
 static void
 print_get_error(struct tcb *const tcp, const kernel_ulong_t addr,
-		unsigned int len)
+		const unsigned int len)
 {
 	unsigned int err;
 
-	if (len > sizeof(err))
-		len = sizeof(err);
+	if (len < sizeof(err)) {
+		printstrn(tcp, addr, len);
+		return;
+	}
 
-	if (umoven_or_printaddr(tcp, addr, len, &err))
+	if (umove_or_printaddr(tcp, addr, &err))
 		return;
 
 	tprint_indirect_begin();