From: Arjan van de Ven Date: Sat, 25 Oct 2008 19:41:41 +0000 (-0700) Subject: select: deal with math overflow from borderline valid userland data X-Git-Tag: v2.6.28-rc2~3 X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?p=linux-2.6-omap-h63xx.git;a=commitdiff_plain;h=4d36a9e65d4966b433b2f3424d9457468bc80e00 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 --- diff --git a/fs/compat.c b/fs/compat.c index fe3c9bf8760..e5f49f53850 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 448e4400128..87df51eadcf 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; }