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[PATCH] select: time comparison fixes

I got all of these backwards.  We want to return

	min(input timeout, new timeout)

to userspace to prevent increasing the time-remaining value.

Thanks to Ernst Herzberg <earny@net4u.de> for reporting and diagnosing.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Andrew Morton 19 年之前
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74910e6c7d
共有 2 个文件被更改,包括 6 次插入6 次删除
  1. 3 3
      fs/compat.c
  2. 3 3
      fs/select.c

+ 3 - 3
fs/compat.c

@@ -1757,7 +1757,7 @@ asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp,
 			goto sticky;
 			goto sticky;
 		rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
 		rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
 		rtv.tv_sec = timeout;
 		rtv.tv_sec = timeout;
-		if (compat_timeval_compare(&rtv, &tv) < 0)
+		if (compat_timeval_compare(&rtv, &tv) >= 0)
 			rtv = tv;
 			rtv = tv;
 		if (copy_to_user(tvp, &rtv, sizeof(rtv))) {
 		if (copy_to_user(tvp, &rtv, sizeof(rtv))) {
 sticky:
 sticky:
@@ -1834,7 +1834,7 @@ asmlinkage long compat_sys_pselect7(int n, compat_ulong_t __user *inp,
 			rts.tv_sec++;
 			rts.tv_sec++;
 			rts.tv_nsec -= NSEC_PER_SEC;
 			rts.tv_nsec -= NSEC_PER_SEC;
 		}
 		}
-		if (compat_timespec_compare(&rts, &ts) < 0)
+		if (compat_timespec_compare(&rts, &ts) >= 0)
 			rts = ts;
 			rts = ts;
 		copy_to_user(tsp, &rts, sizeof(rts));
 		copy_to_user(tsp, &rts, sizeof(rts));
 	}
 	}
@@ -1934,7 +1934,7 @@ asmlinkage long compat_sys_ppoll(struct pollfd __user *ufds,
 		rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
 		rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
 					1000;
 					1000;
 		rts.tv_sec = timeout;
 		rts.tv_sec = timeout;
-		if (compat_timespec_compare(&rts, &ts) < 0)
+		if (compat_timespec_compare(&rts, &ts) >= 0)
 			rts = ts;
 			rts = ts;
 		if (copy_to_user(tsp, &rts, sizeof(rts))) {
 		if (copy_to_user(tsp, &rts, sizeof(rts))) {
 sticky:
 sticky:

+ 3 - 3
fs/select.c

@@ -404,7 +404,7 @@ asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
 			goto sticky;
 			goto sticky;
 		rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
 		rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
 		rtv.tv_sec = timeout;
 		rtv.tv_sec = timeout;
-		if (timeval_compare(&rtv, &tv) < 0)
+		if (timeval_compare(&rtv, &tv) >= 0)
 			rtv = tv;
 			rtv = tv;
 		if (copy_to_user(tvp, &rtv, sizeof(rtv))) {
 		if (copy_to_user(tvp, &rtv, sizeof(rtv))) {
 sticky:
 sticky:
@@ -471,7 +471,7 @@ asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp,
 		rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
 		rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
 						1000;
 						1000;
 		rts.tv_sec = timeout;
 		rts.tv_sec = timeout;
-		if (timespec_compare(&rts, &ts) < 0)
+		if (timespec_compare(&rts, &ts) >= 0)
 			rts = ts;
 			rts = ts;
 		if (copy_to_user(tsp, &rts, sizeof(rts))) {
 		if (copy_to_user(tsp, &rts, sizeof(rts))) {
 sticky:
 sticky:
@@ -775,7 +775,7 @@ asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds,
 		rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
 		rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
 						1000;
 						1000;
 		rts.tv_sec = timeout;
 		rts.tv_sec = timeout;
-		if (timespec_compare(&rts, &ts) < 0)
+		if (timespec_compare(&rts, &ts) >= 0)
 			rts = ts;
 			rts = ts;
 		if (copy_to_user(tsp, &rts, sizeof(rts))) {
 		if (copy_to_user(tsp, &rts, sizeof(rts))) {
 		sticky:
 		sticky: