| Date | Tue, 02 Oct 2012 00:52:58 +0200 | From | Willy Tarreau <> | Subject | [ 061/180] ntp: Fix integer overflow when setting time |
| |
2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------
From: Sasha Levin <levinsasha928@gmail.com>
commit a078c6d0e6288fad6d83fb6d5edd91ddb7b6ab33 upstream.
'long secs' is passed as divisor to div_s64, which accepts a 32bit divisor. On 64bit machines that value is trimmed back from 8 bytes back to 4, causing a divide by zero when the number is bigger than (1 << 32) - 1 and all 32 lower bits are 0.
Use div64_long() instead.
Signed-off-by: Sasha Levin <levinsasha928@gmail.com> Cc: johnstul@us.ibm.com Link: http://lkml.kernel.org/r/1331829374-31543-2-git-send-email-levinsasha928@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [WT: div64_long() does not exist on 2.6.32 and needs a deeper backport than desired. Instead, address the issue by controlling that the divisor is correct for use as an s32 divisor] Signed-off-by: Willy Tarreau <w@1wt.eu> --- kernel/time/ntp.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index c1c36a2..26472a7 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -106,7 +106,7 @@ static inline s64 ntp_update_offset_fll(s64 offset64, long secs) { time_status &= ~STA_MODE; - if (secs < MINSEC) + if ((s32)secs < MINSEC) return 0; if (!(time_status & STA_FLL) && (secs <= MAXSEC)) -- 1.7.2.1.45.g54fbc
|