4 files changed, 56 insertions, 15 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index f0f4ab36c444..6d98566201ef 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1020,7 +1020,7 @@ const struct file_operations pipefifo_fops = {
  * Currently we rely on the pipe array holding a power-of-2 number
  * of pages. Returns 0 on error.
  */
-static inline unsigned int round_pipe_size(unsigned int size)
+unsigned int round_pipe_size(unsigned int size)
 {
 	unsigned long nr_pages;
 
@@ -1125,25 +1125,13 @@ out_revert_acct:
 }
 
 /*
- * This should work even if CONFIG_PROC_FS isn't set, as proc_dointvec_minmax
+ * This should work even if CONFIG_PROC_FS isn't set, as proc_dopipe_max_size
  * will return an error.
  */
 int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf,
 		 size_t *lenp, loff_t *ppos)
 {
-	unsigned int rounded_pipe_max_size;
-	int ret;
-
-	ret = proc_douintvec_minmax(table, write, buf, lenp, ppos);
-	if (ret < 0 || !write)
-		return ret;
-
-	rounded_pipe_max_size = round_pipe_size(pipe_max_size);
-	if (rounded_pipe_max_size == 0)
-		return -EINVAL;
-
-	pipe_max_size = rounded_pipe_max_size;
-	return ret;
+	return proc_dopipe_max_size(table, write, buf, lenp, ppos);
 }
 
 /*
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 6a80cfc63e0c..2dc5e9870fcd 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -191,5 +191,6 @@ long pipe_fcntl(struct file *, unsigned int, unsigned long arg);
 struct pipe_inode_info *get_pipe_info(struct file *file);
 
 int create_pipe_files(struct file **, int);
+unsigned int round_pipe_size(unsigned int size);
 
 #endif
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index b769ecfcc3bd..992bc9948232 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -51,6 +51,9 @@ extern int proc_dointvec_minmax(struct ctl_table *, int,
 extern int proc_douintvec_minmax(struct ctl_table *table, int write,
 				 void __user *buffer, size_t *lenp,
 				 loff_t *ppos);
+extern int proc_dopipe_max_size(struct ctl_table *table, int write,
+				void __user *buffer, size_t *lenp,
+				loff_t *ppos);
 extern int proc_dointvec_jiffies(struct ctl_table *, int,
 				 void __user *, size_t *, loff_t *);
 extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int,
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 2d42183b4c98..138b6484f277 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/pipe_fs_i.h>
 
 #include <linux/uaccess.h>
 #include <asm/processor.h>
@@ -2620,6 +2621,47 @@ int proc_douintvec_minmax(struct ctl_table *table, int write,
 				 do_proc_douintvec_minmax_conv, &param);
 }
 
+struct do_proc_dopipe_max_size_conv_param {
+	unsigned int *min;
+};
+
+static int do_proc_dopipe_max_size_conv(unsigned long *lvalp,
+					unsigned int *valp,
+					int write, void *data)
+{
+	struct do_proc_dopipe_max_size_conv_param *param = data;
+
+	if (write) {
+		unsigned int val = round_pipe_size(*lvalp);
+
+		if (val == 0)
+			return -EINVAL;
+
+		if (param->min && *param->min > val)
+			return -ERANGE;
+
+		if (*lvalp > UINT_MAX)
+			return -EINVAL;
+
+		*valp = val;
+	} else {
+		unsigned int val = *valp;
+		*lvalp = (unsigned long) val;
+	}
+
+	return 0;
+}
+
+int proc_dopipe_max_size(struct ctl_table *table, int write,
+			 void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct do_proc_dopipe_max_size_conv_param param = {
+		.min = (unsigned int *) table->extra1,
+	};
+	return do_proc_douintvec(table, write, buffer, lenp, ppos,
+				 do_proc_dopipe_max_size_conv, &param);
+}
+
 static void validate_coredump_safety(void)
 {
 #ifdef CONFIG_COREDUMP
@@ -3125,6 +3167,12 @@ int proc_douintvec_minmax(struct ctl_table *table, int write,
 	return -ENOSYS;
 }
 
+int proc_dopipe_max_size(struct ctl_table *table, int write,
+			 void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
 int proc_dointvec_jiffies(struct ctl_table *table, int write,
 		    void __user *buffer, size_t *lenp, loff_t *ppos)
 {
@@ -3168,6 +3216,7 @@ EXPORT_SYMBOL(proc_douintvec);
 EXPORT_SYMBOL(proc_dointvec_jiffies);
 EXPORT_SYMBOL(proc_dointvec_minmax);
 EXPORT_SYMBOL_GPL(proc_douintvec_minmax);
+EXPORT_SYMBOL_GPL(proc_dopipe_max_size);
 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
 EXPORT_SYMBOL(proc_dostring);