[PATCH 2/5] linux-uesr: make exec_path realpath

From: YAMAMOTO Takashi <yamamoto@midokura.com>
To: qemu-devel@nongnu.org
Cc: YAMAMOTO Takashi <yamamoto@midokura.com>,
	Laurent Vivier <laurent@vivier.eu>
Subject: [PATCH 2/5] linux-uesr: make exec_path realpath
Date: Mon, 24 May 2021 13:54:08 +0900	[thread overview]
Message-ID: <20210524045412.15152-3-yamamoto@midokura.com> (raw)
In-Reply-To: <20210524045412.15152-1-yamamoto@midokura.com>

Otherwise, it can be easily fooled by the user app using chdir().

Signed-off-by: YAMAMOTO Takashi <yamamoto@midokura.com>
---
 linux-user/main.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/linux-user/main.c b/linux-user/main.c
index 4dfc47ad3b..1f9f4e3820 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -55,6 +55,7 @@
 #endif
 
 char *exec_path;
+char exec_path_store[PATH_MAX];
 
 int singlestep;
 static const char *argv0;
@@ -610,7 +611,10 @@ static int parse_args(int argc, char **argv)
         exit(EXIT_FAILURE);
     }
 
-    exec_path = argv[optind];
+    exec_path = realpath(argv[optind], exec_path_store);
+    if (exec_path == NULL) {
+        exec_path = argv[optind];
+    }
 
     return optind;
 }
-- 
2.21.1 (Apple Git-122.3)


