From 4d36a9e65d4966b433b2f3424d9457468bc80e00 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Sat, 25 Oct 2008 12:41:41 -0700 Subject: [PATCH] select: deal with math overflow from borderline valid userland data Some userland apps seem to pass in a "0" for the seconds, and several seconds worth of usecs to select(). The old kernels accepted this just fine, so the new kernels must too. However, due to the upscaling of the microseconds to nanoseconds we had some cases where we got math overflow, and depending on the GCC version (due to inlining decisions) that actually resulted in an -EINVAL return. This patch fixes this by adding the excess microseconds to the seconds field. Also with thanks to Marcin Slusarz for spotting some implementation bugs in the diagnostics patches. Reported-by: Carlos R. Mafra Signed-off-by: Arjan van de Ven Signed-off-by: Linus Torvalds --- fs/compat.c | 5 +++-- fs/select.c | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/compat.c b/fs/compat.c index fe3c9bf87608..e5f49f538502 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -1684,8 +1684,9 @@ asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp, return -EFAULT; to = &end_time; - if (poll_select_set_timeout(to, tv.tv_sec, - tv.tv_usec * NSEC_PER_USEC)) + if (poll_select_set_timeout(to, + tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), + (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) return -EINVAL; } diff --git a/fs/select.c b/fs/select.c index 448e44001286..87df51eadcf2 100644 --- a/fs/select.c +++ b/fs/select.c @@ -519,8 +519,9 @@ asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp, return -EFAULT; to = &end_time; - if (poll_select_set_timeout(to, tv.tv_sec, - tv.tv_usec * NSEC_PER_USEC)) + if (poll_select_set_timeout(to, + tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), + (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) return -EINVAL; }