[PATCH] Check maxlen on strnlen_user usage

From: Ryan Mallon
Date: Thu Sep 01 2011 - 19:39:23 EST


strnlen_user returns the length of the string including the nul terminator. In the case where maxlen is reached strnlen_user returns maxlen + 1. Most callsites already check for this condition. Fix the call to strnlen_user in fs/exec.c to check for the maxlen case.

Signed-off-by: Ryan Mallon <rmallon@xxxxxxxxx>
---

diff --git a/fs/exec.c b/fs/exec.c
index 25dcbe5..e19588c 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -481,7 +481,7 @@ static int copy_strings(int argc, struct user_arg_ptr argv,
goto out;

len = strnlen_user(str, MAX_ARG_STRLEN);
- if (!len)
+ if (!len || len> MAX_ARG_STRLEN)
goto out;

ret = -E2BIG;

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