1 files changed, 52 insertions, 7 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c9ec050bcf46..943c89178e3d 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -66,6 +66,7 @@
 #include <linux/kexec.h>
 #include <linux/bpf.h>
 #include <linux/mount.h>
+#include <linux/userfaultfd_k.h>
 
 #include "../lib/kstrtox.h"
 
@@ -1720,6 +1721,17 @@ static struct ctl_table vm_table[] = {
 		.extra2		= (void *)&mmap_rnd_compat_bits_max,
 	},
 #endif
+#ifdef CONFIG_USERFAULTFD
+	{
+		.procname	= "unprivileged_userfaultfd",
+		.data		= &sysctl_unprivileged_userfaultfd,
+		.maxlen		= sizeof(sysctl_unprivileged_userfaultfd),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &one,
+	},
+#endif
 	{ }
 };
 
@@ -2874,8 +2886,10 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int
 			if (neg)
 				continue;
 			val = convmul * val / convdiv;
-			if ((min && val < *min) || (max && val > *max))
-				continue;
+			if ((min && val < *min) || (max && val > *max)) {
+				err = -EINVAL;
+				break;
+			}
 			*i = val;
 		} else {
 			val = convdiv * (*i) / convmul;
@@ -3158,17 +3172,19 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
 
 	if (write) {
 		char *kbuf, *p;
+		size_t skipped = 0;
 
-		if (left > PAGE_SIZE - 1)
+		if (left > PAGE_SIZE - 1) {
 			left = PAGE_SIZE - 1;
+			/* How much of the buffer we'll skip this pass */
+			skipped = *lenp - left;
+		}
 
 		p = kbuf = memdup_user_nul(buffer, left);
 		if (IS_ERR(kbuf))
 			return PTR_ERR(kbuf);
 
-		tmp_bitmap = kcalloc(BITS_TO_LONGS(bitmap_len),
-				     sizeof(unsigned long),
-				     GFP_KERNEL);
+		tmp_bitmap = bitmap_zalloc(bitmap_len, GFP_KERNEL);
 		if (!tmp_bitmap) {
 			kfree(kbuf);
 			return -ENOMEM;
@@ -3177,9 +3193,22 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
 		while (!err && left) {
 			unsigned long val_a, val_b;
 			bool neg;
+			size_t saved_left;
 
+			/* In case we stop parsing mid-number, we can reset */
+			saved_left = left;
 			err = proc_get_long(&p, &left, &val_a, &neg, tr_a,
 					     sizeof(tr_a), &c);
+			/*
+			 * If we consumed the entirety of a truncated buffer or
+			 * only one char is left (may be a "-"), then stop here,
+			 * reset, & come back for more.
+			 */
+			if ((left <= 1) && skipped) {
+				left = saved_left;
+				break;
+			}
+
 			if (err)
 				break;
 			if (val_a >= bitmap_len || neg) {
@@ -3197,6 +3226,15 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
 				err = proc_get_long(&p, &left, &val_b,
 						     &neg, tr_b, sizeof(tr_b),
 						     &c);
+				/*
+				 * If we consumed all of a truncated buffer or
+				 * then stop here, reset, & come back for more.
+				 */
+				if (!left && skipped) {
+					left = saved_left;
+					break;
+				}
+
 				if (err)
 					break;
 				if (val_b >= bitmap_len || neg ||
@@ -3215,6 +3253,7 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
 			proc_skip_char(&p, &left, '\n');
 		}
 		kfree(kbuf);
+		left += skipped;
 	} else {
 		unsigned long bit_a, bit_b = 0;
 
@@ -3259,7 +3298,7 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
 		*ppos += *lenp;
 	}
 
-	kfree(tmp_bitmap);
+	bitmap_free(tmp_bitmap);
 	return err;
 }
 
@@ -3326,6 +3365,11 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
     return -ENOSYS;
 }
 
+int proc_do_large_bitmap(struct ctl_table *table, int write,
+			 void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
 
 #endif /* CONFIG_PROC_SYSCTL */
 
@@ -3366,3 +3410,4 @@ EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
 EXPORT_SYMBOL(proc_dostring);
 EXPORT_SYMBOL(proc_doulongvec_minmax);
 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
+EXPORT_SYMBOL(proc_do_large_bitmap);