From 06784d7fc6761528d587837b241d27c6d17c0842 Mon Sep 17 00:00:00 2001
From: Stefano Brivio <sbrivio@redhat.com>
Date: Thu, 3 Apr 2025 19:01:02 +0200
Subject: [PATCH] passt-repair: Ensure that read buffer is NULL-terminated
After 3d41e4d83895 ("passt-repair: Correct off-by-one error verifying
name"), Coverity Scan isn't convinced anymore about the fact that the
ev->name used in the snprintf() is NULL-terminated.
It comes from a read() call, and read() of course doesn't terminate
it, but we already check that the byte at ev->len - 1 is a NULL
terminator, so this is actually a false positive.
In any case, the logic ensuring that ev->name is NULL-terminated isn't
necessarily obvious, and additionally checking that the last byte in
the buffer we read is a NULL terminator is harmless, so do that
explicitly, even if it's redundant.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
passt-repair.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/passt-repair.c b/passt-repair.c
index 440c77a..256a8c9 100644
--- a/passt-repair.c
+++ b/passt-repair.c
@@ -137,6 +137,7 @@ int main(int argc, char **argv)
fprintf(stderr, "inotify read: %i", errno);
_exit(1);
}
+ buf[n - 1] = '\0';
if (n < (ssize_t)sizeof(*ev)) {
fprintf(stderr, "Short inotify read: %zi", n);