4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liping Zhang <zlpnobody@xxxxxxxxx> 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@xxxxxxxxx> Cc: Subash Abhinov Kasiviswanathan <subashab@xxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/sysctl.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2067,6 +2067,8 @@ static int do_proc_douintvec_conv(bool * if (write) { if (*negp) return -EINVAL; + if (*lvalp > UINT_MAX) + return -EINVAL; *valp = *lvalp; } else { unsigned int val = *valp;