sysctl: report EINVAL if value is larger than UINT_MAX for proc_douintvec

commit 425fffd886bae3d127a08fa6a17f2e31e24ed7ff upstream.

Currently, inputting the following command will succeed but actually the
value will be truncated:

  # echo 0x12ffffffff > /proc/sys/net/ipv4/tcp_notsent_lowat

This is not friendly to the user, so instead, we should report error
when the value is larger than UINT_MAX.

Fixes: e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index e8c1743fcc103de9b6c36e3db91e1ceda557b50d..265e0d0216e35d2a1fd144b92a3d2add6a1d76f2 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2146,6 +2146,8 @@ static int do_proc_douintvec_conv(bool *negp, unsigned long *lvalp,
        if (write) {
                if (*negp)
                        return -EINVAL;
+               if (*lvalp > UINT_MAX)
+                       return -EINVAL;
                *valp = *lvalp;
        } else {
                unsigned int val = *valp;