commit 4837df6e6f89b1d9b57a0a8c95c4f35385d63f16
author Andrew Jones <drjones@redhat.com> Wed Oct 14 21:14:42 2020 +0200
committer Paolo Bonzini <pbonzini@redhat.com> Thu Nov 19 12:26:55 2020 -0500
tree 41b72cd80ff62018cee1fc2080e5bfe52860c051
parent 1c320e1842dbd9a85d4d975e5c2f287890dd50e5

lib/string: Fix getenv name matching

Without confirming that the name length exactly matches too, then
the string comparison would return the same value for VAR* as for
VAR, when VAR came first in the environ array.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Message-Id: <20201014191444.136782-2-drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

lib/string.c

diff --git a/lib/string.c b/lib/string.c
index 018dcc8..75257f5 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -171,10 +171,13 @@
 char *getenv(const char *name)
 {
     char **envp = environ, *delim;
+    int len;
 
     while (*envp) {
         delim = strchr(*envp, '=');
-        if (delim && strncmp(name, *envp, delim - *envp) == 0)
+        assert(delim);
+        len = delim - *envp;
+        if (memcmp(name, *envp, len) == 0 && !name[len])
             return delim + 1;
         ++envp;
     }