[net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[Octavian Purdila]

This patch introduces /proc/sys/net/ipv4/ip_local_reserved_ports which
allows users to reserve ports for third-party applications.

The reserved ports will not be used by automatic port assignments
(e.g. when calling connect() or bind() with port number 0). Explicit
port allocation behavior is unchanged.

Changes from the previous version:
- be more strict on accepted input (only comma separators, no spaces allowed)
- add to the docs a paragraph about ip_local_port_range and
  ip_local_reserved_ports relationship
- fix a few corner cases with parsing

There are still some miss behaviors with regard to proc parsing in odd
invalid cases (for "40000\0-40001" all is acknowledged but only 40000
is accepted) but they are not easy to fix without changing the current
"acknowledge how much we accepted" behavior.

Because of that and because the same issues are present in the
existing proc_dointvec code as well I don't think its worth holding
the actual feature (port reservation) after such petty error recovery
issues.

For the sake of discussion, I think Eric was right: the model we are
using is messy, we should only accept all input or none. If we can
(ABI implications) and you think its worth switching to this model I
can give it a try in a future patch.

Octavian Purdila (3):
  sysctl: refactor integer handling proc code
  sysctl: add proc_do_large_bitmap
  net: reserve ports for applications using fixed port numbers

 Documentation/networking/ip-sysctl.txt |   31 ++
 drivers/infiniband/core/cma.c          |    7 +-
 include/linux/sysctl.h                 |    2 +
 include/net/ip.h                       |    6 +
 kernel/sysctl.c                        |  504 ++++++++++++++++++++++----------
 net/ipv4/af_inet.c                     |    8 +-
 net/ipv4/inet_connection_sock.c        |    6 +
 net/ipv4/inet_hashtables.c             |    2 +
 net/ipv4/sysctl_net_ipv4.c             |   17 +
 net/ipv4/udp.c                         |    3 +-
 net/sctp/socket.c                      |    2 +
 11 files changed, 431 insertions(+), 157 deletions(-)

[net-next PATCH v6 1/3] sysctl: refactor integer handling proc code

[Octavian Purdila]

As we are about to add another integer handling proc function a little
bit of cleanup is in order: add a few helper functions to improve code
readability and decrease code duplication.

In the process a bug is also fixed: if the user specifies a number
with more then 20 digits it will be interpreted as two integers
(e.g. 10000...13 will be interpreted as 100.... and 13).

Behavior for EFAULT handling was changed as well. Previous to this
patch, when an EFAULT error occurred in the middle of a write
operation, although some of the elements were set, that was not
acknowledged to the user (by shorting the write and returning the
number of bytes accepted). EFAULT is now treated just like any other
errors by acknowledging the amount of bytes accepted.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Cc: WANG Cong <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
---
 kernel/sysctl.c |  364 ++++++++++++++++++++++++++++++++-----------------------
 1 files changed, 210 insertions(+), 154 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 8a68b24..0873846 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2039,8 +2039,148 @@ int proc_dostring(struct ctl_table *table, int write,
 			       buffer, lenp, ppos);
 }
 
+static int proc_skip_wspace(char __user **buf, size_t *size)
+{
+	char c;
+
+	while (*size) {
+		if (get_user(c, *buf))
+			return -EFAULT;
+		if (!isspace(c))
+			break;
+		(*size)--;
+		(*buf)++;
+	}
+
+	return 0;
+}
+
+static bool isanyof(char c, const char *v, unsigned len)
+{
+	int i;
+
+	if (!len)
+		return false;
+
+	for (i = 0; i < len; i++)
+		if (c == v[i])
+			break;
+	if (i == len)
+		return false;
+
+	return true;
+}
+
+#define TMPBUFLEN 22
+/**
+ * proc_get_ulong - reads an ASCII formated integer from a user buffer
+ *
+ * @buf - user buffer
+ * @size - size of the user buffer
+ * @val - this is where the number will be stored
+ * @neg - set to %TRUE if number is negative
+ * @perm_tr - a vector which contains the allowed trailers
+ * @perm_tr_len - size of the perm_tr vector
+ * @tr - pointer to store the trailer character
+ *
+ * In case of success 0 is returned and buf and size are updated with
+ * the amount of bytes read. If tr is non NULL and a trailing
+ * character exist (size is non zero after returning from this
+ * function) tr is updated with the trailing character.
+ */
+static int proc_get_ulong(char __user **buf, size_t *size,
+			  unsigned long *val, bool *neg,
+			  const char *perm_tr, unsigned perm_tr_len, char *tr)
+{
+	int len;
+	char *p, tmp[TMPBUFLEN];
+
+	if (!*size)
+		return -EINVAL;
+
+	len = *size;
+	if (len > TMPBUFLEN-1)
+		len = TMPBUFLEN-1;
+
+	if (copy_from_user(tmp, *buf, len))
+		return -EFAULT;
+
+	tmp[len] = 0;
+	p = tmp;
+	if (*p == '-' && *size > 1) {
+		*neg = 1;
+		p++;
+	} else
+		*neg = 0;
+	if (!isdigit(*p))
+		return -EINVAL;
+
+	*val = simple_strtoul(p, &p, 0);
+
+	len = p - tmp;
+
+	/* We don't know if the next char is whitespace thus we may accept
+	 * invalid integers (e.g. 1234...a) or two integers instead of one
+	 * (e.g. 123...1). So lets not allow such large numbers. */
+	if (len == TMPBUFLEN - 1)
+		return -EINVAL;
+
+	if (len < *size && perm_tr_len && !isanyof(*p, perm_tr, perm_tr_len))
+		return -EINVAL;
+
+	if (tr && (len < *size))
+		*tr = *p;
+
+	*buf += len;
+	*size -= len;
+
+	return 0;
+}
+
+/**
+ * proc_put_ulong - coverts an integer to a decimal ASCII formated string
+ *
+ * @buf - the user buffer
+ * @size - the size of the user buffer
+ * @val - the integer to be converted
+ * @neg - sign of the number, %TRUE for negative
+ * @first - if %FALSE will insert a separator character before the number
+ * @separator - the separator character
+ *
+ * In case of success 0 is returned and buf and size are updated with
+ * the amount of bytes read.
+ */
+static int proc_put_ulong(char __user **buf, size_t *size, unsigned long val,
+			  bool neg, bool first, char separator)
+{
+	int len;
+	char tmp[TMPBUFLEN], *p = tmp;
+
+	if (!first)
+		*p++ = separator;
+	sprintf(p, "%s%lu", neg ? "-" : "", val);
+	len = strlen(tmp);
+	if (len > *size)
+		len = *size;
+	if (copy_to_user(*buf, tmp, len))
+		return -EFAULT;
+	*size -= len;
+	*buf += len;
+	return 0;
+}
+#undef TMPBUFLEN
+
+static int proc_put_char(char __user **buf, size_t *size, char c)
+{
+	if (*size) {
+		if (put_user(c, *buf))
+			return -EFAULT;
+		(*size)--, (*buf)++;
+	}
+	return 0;
+}
 
-static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
+static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
 				 int *valp,
 				 int write, void *data)
 {
@@ -2049,7 +2189,7 @@ static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
 	} else {
 		int val = *valp;
 		if (val < 0) {
-			*negp = -1;
+			*negp = 1;
 			*lvalp = (unsigned long)-val;
 		} else {
 			*negp = 0;
@@ -2059,20 +2199,18 @@ static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
 	return 0;
 }
 
+static const char proc_wspace_sep[] = { ' ', '\t', '\n', 0 };
+
 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
-		  int write, void __user *buffer,
+		  int write, void __user *_buffer,
 		  size_t *lenp, loff_t *ppos,
-		  int (*conv)(int *negp, unsigned long *lvalp, int *valp,
+		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
 			      int write, void *data),
 		  void *data)
 {
-#define TMPBUFLEN 21
-	int *i, vleft, first = 1, neg;
-	unsigned long lval;
-	size_t left, len;
-	
-	char buf[TMPBUFLEN], *p;
-	char __user *s = buffer;
+	int *i, vleft, first = 1, err = 0;
+	size_t left;
+	char __user *buffer = (char __user *) _buffer;
 	
 	if (!tbl_data || !table->maxlen || !*lenp ||
 	    (*ppos && !write)) {
@@ -2088,88 +2226,48 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
 		conv = do_proc_dointvec_conv;
 
 	for (; left && vleft--; i++, first=0) {
-		if (write) {
-			while (left) {
-				char c;
-				if (get_user(c, s))
-					return -EFAULT;
-				if (!isspace(c))
-					break;
-				left--;
-				s++;
-			}
-			if (!left)
-				break;
-			neg = 0;
-			len = left;
-			if (len > sizeof(buf) - 1)
-				len = sizeof(buf) - 1;
-			if (copy_from_user(buf, s, len))
-				return -EFAULT;
-			buf[len] = 0;
-			p = buf;
-			if (*p == '-' && left > 1) {
-				neg = 1;
-				p++;
-			}
-			if (*p < '0' || *p > '9')
-				break;
-
-			lval = simple_strtoul(p, &p, 0);
+		unsigned long lval;
+		bool neg;
 
-			len = p-buf;
-			if ((len < left) && *p && !isspace(*p))
+		if (write) {
+			err = proc_skip_wspace(&buffer, &left);
+			if (err)
+				return err;
+			err = proc_get_ulong(&buffer, &left, &lval, &neg,
+					     proc_wspace_sep,
+					     sizeof(proc_wspace_sep), NULL);
+			if (err)
 				break;
-			s += len;
-			left -= len;
-
-			if (conv(&neg, &lval, i, 1, data))
+			if (conv(&neg, &lval, i, 1, data)) {
+				err = -EINVAL;
 				break;
+			}
 		} else {
-			p = buf;
-			if (!first)
-				*p++ = '\t';
-	
-			if (conv(&neg, &lval, i, 0, data))
+			if (conv(&neg, &lval, i, 0, data)) {
+				err = -EINVAL;
 				break;
-
-			sprintf(p, "%s%lu", neg ? "-" : "", lval);
-			len = strlen(buf);
-			if (len > left)
-				len = left;
-			if(copy_to_user(s, buf, len))
-				return -EFAULT;
-			left -= len;
-			s += len;
-		}
-	}
-
-	if (!write && !first && left) {
-		if(put_user('\n', s))
-			return -EFAULT;
-		left--, s++;
-	}
-	if (write) {
-		while (left) {
-			char c;
-			if (get_user(c, s++))
-				return -EFAULT;
-			if (!isspace(c))
+			}
+			err = proc_put_ulong(&buffer, &left, lval, neg, first,
+					     '\t');
+			if (err)
 				break;
-			left--;
 		}
 	}
+
+	if (!write && !first && left && !err)
+		err = proc_put_char(&buffer, &left, '\n');
+	if (write && !err)
+		err = proc_skip_wspace(&buffer, &left);
 	if (write && first)
-		return -EINVAL;
+		return err ? : -EINVAL;
 	*lenp -= left;
 	*ppos += *lenp;
 	return 0;
-#undef TMPBUFLEN
 }
 
 static int do_proc_dointvec(struct ctl_table *table, int write,
 		  void __user *buffer, size_t *lenp, loff_t *ppos,
-		  int (*conv)(int *negp, unsigned long *lvalp, int *valp,
+		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
 			      int write, void *data),
 		  void *data)
 {
@@ -2237,8 +2335,8 @@ struct do_proc_dointvec_minmax_conv_param {
 	int *max;
 };
 
-static int do_proc_dointvec_minmax_conv(int *negp, unsigned long *lvalp, 
-					int *valp, 
+static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
+					int *valp,
 					int write, void *data)
 {
 	struct do_proc_dointvec_minmax_conv_param *param = data;
@@ -2251,7 +2349,7 @@ static int do_proc_dointvec_minmax_conv(int *negp, unsigned long *lvalp,
 	} else {
 		int val = *valp;
 		if (val < 0) {
-			*negp = -1;
+			*negp = 1;
 			*lvalp = (unsigned long)-val;
 		} else {
 			*negp = 0;
@@ -2289,17 +2387,15 @@ int proc_dointvec_minmax(struct ctl_table *table, int write,
 }
 
 static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
-				     void __user *buffer,
+				     void __user *_buffer,
 				     size_t *lenp, loff_t *ppos,
 				     unsigned long convmul,
 				     unsigned long convdiv)
 {
-#define TMPBUFLEN 21
-	unsigned long *i, *min, *max, val;
-	int vleft, first=1, neg;
-	size_t len, left;
-	char buf[TMPBUFLEN], *p;
-	char __user *s = buffer;
+	unsigned long *i, *min, *max;
+	int vleft, first = 1, err = 0;
+	size_t left;
+	char __user *buffer = (char __user *) _buffer;
 	
 	if (!data || !table->maxlen || !*lenp ||
 	    (*ppos && !write)) {
@@ -2314,82 +2410,42 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int
 	left = *lenp;
 	
 	for (; left && vleft--; i++, min++, max++, first=0) {
+		unsigned long val;
+
 		if (write) {
-			while (left) {
-				char c;
-				if (get_user(c, s))
-					return -EFAULT;
-				if (!isspace(c))
-					break;
-				left--;
-				s++;
-			}
-			if (!left)
-				break;
-			neg = 0;
-			len = left;
-			if (len > TMPBUFLEN-1)
-				len = TMPBUFLEN-1;
-			if (copy_from_user(buf, s, len))
-				return -EFAULT;
-			buf[len] = 0;
-			p = buf;
-			if (*p == '-' && left > 1) {
-				neg = 1;
-				p++;
-			}
-			if (*p < '0' || *p > '9')
-				break;
-			val = simple_strtoul(p, &p, 0) * convmul / convdiv ;
-			len = p-buf;
-			if ((len < left) && *p && !isspace(*p))
+			bool neg;
+
+			err = proc_skip_wspace(&buffer, &left);
+			if (err)
+				return err;
+			err = proc_get_ulong(&buffer, &left, &val, &neg,
+					     proc_wspace_sep,
+					     sizeof(proc_wspace_sep), NULL);
+			if (err)
 				break;
 			if (neg)
-				val = -val;
-			s += len;
-			left -= len;
-
-			if(neg)
 				continue;
 			if ((min && val < *min) || (max && val > *max))
 				continue;
 			*i = val;
 		} else {
-			p = buf;
-			if (!first)
-				*p++ = '\t';
-			sprintf(p, "%lu", convdiv * (*i) / convmul);
-			len = strlen(buf);
-			if (len > left)
-				len = left;
-			if(copy_to_user(s, buf, len))
-				return -EFAULT;
-			left -= len;
-			s += len;
-		}
-	}
-
-	if (!write && !first && left) {
-		if(put_user('\n', s))
-			return -EFAULT;
-		left--, s++;
-	}
-	if (write) {
-		while (left) {
-			char c;
-			if (get_user(c, s++))
-				return -EFAULT;
-			if (!isspace(c))
+			val = convdiv * (*i) / convmul;
+			err = proc_put_ulong(&buffer, &left, val, 0, first,
+					     '\t');
+			if (err)
 				break;
-			left--;
 		}
 	}
+
+	if (!write && !first && left && !err)
+		err = proc_put_char(&buffer, &left, '\n');
+	if (write && !err)
+		err = proc_skip_wspace(&buffer, &left);
 	if (write && first)
-		return -EINVAL;
+		return err ? : -EINVAL;
 	*lenp -= left;
 	*ppos += *lenp;
 	return 0;
-#undef TMPBUFLEN
 }
 
 static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
@@ -2450,7 +2506,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
 }
 
 
-static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
+static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
 					 int *valp,
 					 int write, void *data)
 {
@@ -2462,7 +2518,7 @@ static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
 		int val = *valp;
 		unsigned long lval;
 		if (val < 0) {
-			*negp = -1;
+			*negp = 1;
 			lval = (unsigned long)-val;
 		} else {
 			*negp = 0;
@@ -2473,7 +2529,7 @@ static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
 	return 0;
 }
 
-static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
+static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
 						int *valp,
 						int write, void *data)
 {
@@ -2485,7 +2541,7 @@ static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
 		int val = *valp;
 		unsigned long lval;
 		if (val < 0) {
-			*negp = -1;
+			*negp = 1;
 			lval = (unsigned long)-val;
 		} else {
 			*negp = 0;
@@ -2496,7 +2552,7 @@ static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
 	return 0;
 }
 
-static int do_proc_dointvec_ms_jiffies_conv(int *negp, unsigned long *lvalp,
+static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
 					    int *valp,
 					    int write, void *data)
 {
@@ -2506,7 +2562,7 @@ static int do_proc_dointvec_ms_jiffies_conv(int *negp, unsigned long *lvalp,
 		int val = *valp;
 		unsigned long lval;
 		if (val < 0) {
-			*negp = -1;
+			*negp = 1;
 			lval = (unsigned long)-val;
 		} else {
 			*negp = 0;
-- 
1.5.6.5

[net-next PATCH v6 2/3] sysctl: add proc_do_large_bitmap

[Octavian Purdila]

The new function can be used to read/write large bitmaps via /proc. A
comma separated range format is used for compact output and input
(e.g. 1,3-4,10-10).

Writing into the file will first reset the bitmap then update it
based on the given input.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Cc: WANG Cong <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
---
 include/linux/sysctl.h |    2 +
 kernel/sysctl.c        |  140 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 142 insertions(+), 0 deletions(-)

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index f66014c..7bb5cb6 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -980,6 +980,8 @@ extern int proc_doulongvec_minmax(struct ctl_table *, int,
 				  void __user *, size_t *, loff_t *);
 extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
 				      void __user *, size_t *, loff_t *);
+extern int proc_do_large_bitmap(struct ctl_table *, int,
+				void __user *, size_t *, loff_t *);
 
 /*
  * Register a set of sysctl names by calling register_sysctl_table
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 0873846..5d599cd 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2071,6 +2071,23 @@ static bool isanyof(char c, const char *v, unsigned len)
 	return true;
 }
 
+static int proc_skip_anyof(char __user **buf, size_t *size,
+			   const char *v, unsigned len)
+{
+	char c;
+
+	while (*size) {
+		if (get_user(c, *buf))
+			return -EFAULT;
+		if (!isanyof(c, v, len))
+			break;
+		(*size)--;
+		(*buf)++;
+	}
+
+	return 0;
+}
+
 #define TMPBUFLEN 22
 /**
  * proc_get_ulong - reads an ASCII formated integer from a user buffer
@@ -2662,6 +2679,129 @@ static int proc_do_cad_pid(struct ctl_table *table, int write,
 	return 0;
 }
 
+/**
+ * proc_do_large_bitmap - read/write from/to a large bitmap
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * The bitmap is stored at table->data and the bitmap length (in bits)
+ * in table->maxlen.
+ *
+ * We use a range comma separated format (e.g. 1,3-4,10-10) so that
+ * large bitmaps may be represented in a compact manner. Writing into
+ * the file will clear the bitmap then update it with the given input.
+ *
+ * Returns 0 on success.
+ */
+int proc_do_large_bitmap(struct ctl_table *table, int write,
+			 void __user *_buffer, size_t *lenp, loff_t *ppos)
+{
+	int err = 0;
+	bool first = 1;
+	size_t left = *lenp;
+	unsigned long bitmap_len = table->maxlen;
+	char __user *buffer = (char __user *) _buffer;
+	unsigned long *bitmap = (unsigned long *) table->data;
+	char tr_a[] = { '-', ',', '\n', 0 }, tr_b[] = { ',', '\n', 0 }, c;
+	char tr_end[] = { '\n', 0 };
+
+
+	if (!bitmap_len || !left || (*ppos && !write)) {
+		*lenp = 0;
+		return 0;
+	}
+
+	if (write) {
+		err = proc_skip_anyof(&buffer, &left, tr_end, sizeof(tr_end));
+		while (!err && left) {
+			unsigned long val_a, val_b;
+			bool neg;
+
+			err = proc_get_ulong(&buffer, &left, &val_a, &neg, tr_a,
+					     sizeof(tr_a), &c);
+			if (err)
+				break;
+			if (val_a >= bitmap_len || neg) {
+				err = -EINVAL;
+				break;
+			}
+
+			val_b = val_a;
+			if (left) {
+				buffer++;
+				left--;
+			}
+
+			if (c == '-') {
+				err = proc_get_ulong(&buffer, &left, &val_b,
+						     &neg, tr_b, sizeof(tr_b),
+						     &c);
+				if (err)
+					break;
+				if (val_b >= bitmap_len || neg ||
+				    val_a > val_b) {
+					err = -EINVAL;
+					break;
+				}
+				if (left) {
+					buffer++;
+					left--;
+				}
+			}
+
+			if (first)
+				bitmap_clear(bitmap, 0, bitmap_len);
+
+			while (val_a <= val_b)
+				set_bit(val_a++, bitmap);
+
+			first = 0;
+			err = proc_skip_anyof(&buffer, &left, tr_end,
+					      sizeof(tr_end));
+		}
+	} else {
+		unsigned long bit_a, bit_b = 0;
+
+		while (left) {
+			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
+			if (bit_a >= bitmap_len)
+				break;
+			bit_b = find_next_zero_bit(bitmap, bitmap_len,
+						   bit_a + 1) - 1;
+
+			err = proc_put_ulong(&buffer, &left, bit_a, 0, first,
+					     ',');
+			if (err)
+				break;
+			if (bit_a != bit_b) {
+				err = proc_put_char(&buffer, &left, '-');
+				if (err)
+					break;
+				err = proc_put_ulong(&buffer, &left, bit_b, 0,
+						     1, 0);
+				if (err)
+					break;
+			}
+
+			first = 0; bit_b++;
+		}
+		if (!err)
+			err = proc_put_char(&buffer, &left, '\n');
+	}
+
+	if (first) {
+		if (err)
+			return err;
+		bitmap_clear(bitmap, 0, bitmap_len);
+	}
+	*lenp -= left;
+	*ppos += *lenp;
+	return 0;
+}
+
 #else /* CONFIG_PROC_FS */
 
 int proc_dostring(struct ctl_table *table, int write,
-- 
1.5.6.5

[net-next PATCH v6 3/3] net: reserve ports for applications using fixed port numbers

[Octavian Purdila]

This patch introduces /proc/sys/net/ipv4/ip_local_reserved_ports which
allows users to reserve ports for third-party applications.

The reserved ports will not be used by automatic port assignments
(e.g. when calling connect() or bind() with port number 0). Explicit
port allocation behavior is unchanged.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
---
 Documentation/networking/ip-sysctl.txt |   31 +++++++++++++++++++++++++++++++
 drivers/infiniband/core/cma.c          |    7 ++++++-
 include/net/ip.h                       |    6 ++++++
 net/ipv4/af_inet.c                     |    8 +++++++-
 net/ipv4/inet_connection_sock.c        |    6 ++++++
 net/ipv4/inet_hashtables.c             |    2 ++
 net/ipv4/sysctl_net_ipv4.c             |   17 +++++++++++++++++
 net/ipv4/udp.c                         |    3 ++-
 net/sctp/socket.c                      |    2 ++
 9 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 8b72c88..d0536b5 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -588,6 +588,37 @@ ip_local_port_range - 2 INTEGERS
 	(i.e. by default) range 1024-4999 is enough to issue up to
 	2000 connections per second to systems supporting timestamps.
 
+ip_local_reserved_ports - list of comma separated ranges
+	Specify the ports which are reserved for known third-party
+	applications. These ports will not be used by automatic port
+	assignments (e.g. when calling connect() or bind() with port
+	number 0). Explicit port allocation behavior is unchanged.
+
+	The format used for both input and output is a comma separated
+	list of ranges (e.g. "1,2-4,10-10" for ports 1, 2, 3, 4 and
+	10). Writing to the file will clear all previously reserved
+	ports and update the current list with the one given in the
+	input.
+
+	Note that ip_local_port_range and ip_local_reserved_ports
+	settings are independent and both are considered by the kernel
+	when determining which ports are available for automatic port
+	assignments.
+
+	You can reserve ports which are not in the current
+	ip_local_port_range, e.g.:
+
+	$ cat /proc/sys/net/ipv4/ip_local_port_range
+	32000	61000
+	$ cat /proc/sys/net/ipv4/ip_local_reserved_ports
+	8080,9148
+
+	although this is redundant. However such a setting is useful
+	if later the port range is changed to a value that will
+	include the reserved ports.
+
+	Default: Empty
+
 ip_nonlocal_bind - BOOLEAN
 	If set, allows processes to bind() to non-local IP addresses,
 	which can be quite useful - but may break some applications.
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 875e34e..06c9fa5 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -1979,6 +1979,8 @@ retry:
 	/* FIXME: add proper port randomization per like inet_csk_get_port */
 	do {
 		ret = idr_get_new_above(ps, bind_list, next_port, &port);
+		if (inet_is_reserved_local_port(port))
+			ret = -EAGAIN;
 	} while ((ret == -EAGAIN) && idr_pre_get(ps, GFP_KERNEL));
 
 	if (ret)
@@ -2995,10 +2997,13 @@ static int __init cma_init(void)
 {
 	int ret, low, high, remaining;
 
-	get_random_bytes(&next_port, sizeof next_port);
 	inet_get_local_port_range(&low, &high);
+again:
+	get_random_bytes(&next_port, sizeof next_port);
 	remaining = (high - low) + 1;
 	next_port = ((unsigned int) next_port % remaining) + low;
+	if (inet_is_reserved_local_port(next_port))
+		goto again;
 
 	cma_wq = create_singlethread_workqueue("rdma_cm");
 	if (!cma_wq)
diff --git a/include/net/ip.h b/include/net/ip.h
index 503994a..3da9004 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -184,6 +184,12 @@ extern struct local_ports {
 } sysctl_local_ports;
 extern void inet_get_local_port_range(int *low, int *high);
 
+extern unsigned long *sysctl_local_reserved_ports;
+static inline int inet_is_reserved_local_port(int port)
+{
+	return test_bit(port, sysctl_local_reserved_ports);
+}
+
 extern int sysctl_ip_default_ttl;
 extern int sysctl_ip_nonlocal_bind;
 
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 33b7dff..e283fbe 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1546,9 +1546,13 @@ static int __init inet_init(void)
 
 	BUILD_BUG_ON(sizeof(struct inet_skb_parm) > sizeof(dummy_skb->cb));
 
+	sysctl_local_reserved_ports = kzalloc(65536 / 8, GFP_KERNEL);
+	if (!sysctl_local_reserved_ports)
+		goto out;
+
 	rc = proto_register(&tcp_prot, 1);
 	if (rc)
-		goto out;
+		goto out_free_reserved_ports;
 
 	rc = proto_register(&udp_prot, 1);
 	if (rc)
@@ -1647,6 +1651,8 @@ out_unregister_udp_proto:
 	proto_unregister(&udp_prot);
 out_unregister_tcp_proto:
 	proto_unregister(&tcp_prot);
+out_free_reserved_ports:
+	kfree(sysctl_local_reserved_ports);
 	goto out;
 }
 
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 8da6429..1acb462 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -37,6 +37,9 @@ struct local_ports sysctl_local_ports __read_mostly = {
 	.range = { 32768, 61000 },
 };
 
+unsigned long *sysctl_local_reserved_ports;
+EXPORT_SYMBOL(sysctl_local_reserved_ports);
+
 void inet_get_local_port_range(int *low, int *high)
 {
 	unsigned seq;
@@ -108,6 +111,8 @@ again:
 
 		smallest_size = -1;
 		do {
+			if (inet_is_reserved_local_port(rover))
+				goto next_nolock;
 			head = &hashinfo->bhash[inet_bhashfn(net, rover,
 					hashinfo->bhash_size)];
 			spin_lock(&head->lock);
@@ -130,6 +135,7 @@ again:
 			break;
 		next:
 			spin_unlock(&head->lock);
+		next_nolock:
 			if (++rover > high)
 				rover = low;
 		} while (--remaining > 0);
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 2b79377..d3e160a 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -456,6 +456,8 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 		local_bh_disable();
 		for (i = 1; i <= remaining; i++) {
 			port = low + (i + offset) % remaining;
+			if (inet_is_reserved_local_port(port))
+				continue;
 			head = &hinfo->bhash[inet_bhashfn(net, port,
 					hinfo->bhash_size)];
 			spin_lock(&head->lock);
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index c1bc074..82d3c47 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -298,6 +298,13 @@ static struct ctl_table ipv4_table[] = {
 		.mode		= 0644,
 		.proc_handler	= ipv4_local_port_range,
 	},
+	{
+		.procname	= "ip_local_reserved_ports",
+		.data		= NULL, /* initialized in sysctl_ipv4_init */
+		.maxlen		= 65536,
+		.mode		= 0644,
+		.proc_handler	= proc_do_large_bitmap,
+	},
 #ifdef CONFIG_IP_MULTICAST
 	{
 		.procname	= "igmp_max_memberships",
@@ -735,6 +742,16 @@ static __net_initdata struct pernet_operations ipv4_sysctl_ops = {
 static __init int sysctl_ipv4_init(void)
 {
 	struct ctl_table_header *hdr;
+	struct ctl_table *i;
+
+	for (i = ipv4_table; i->procname; i++) {
+		if (strcmp(i->procname, "ip_local_reserved_ports") == 0) {
+			i->data = sysctl_local_reserved_ports;
+			break;
+		}
+	}
+	if (!i->procname)
+		return -EINVAL;
 
 	hdr = register_sysctl_paths(net_ipv4_ctl_path, ipv4_table);
 	if (hdr == NULL)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 608a544..bfd0a6a 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -232,7 +232,8 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
 			 */
 			do {
 				if (low <= snum && snum <= high &&
-				    !test_bit(snum >> udptable->log, bitmap))
+				    !test_bit(snum >> udptable->log, bitmap) &&
+				    !inet_is_reserved_local_port(snum))
 					goto found;
 				snum += rand;
 			} while (snum != first);
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index f6d1e59..1f839d0 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -5432,6 +5432,8 @@ static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr)
 			rover++;
 			if ((rover < low) || (rover > high))
 				rover = low;
+			if (inet_is_reserved_local_port(rover))
+				continue;
 			index = sctp_phashfn(rover);
 			head = &sctp_port_hashtable[index];
 			sctp_spin_lock(&head->lock);
-- 
1.5.6.5

Re: [net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[David Miller]

Eric B., could you look over the first two patches (which touch the
sysctl core) and give some review and ACK/NACK?

Thanks!

Re: [net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[Cong Wang]

Octavian Purdila wrote:
> This patch introduces /proc/sys/net/ipv4/ip_local_reserved_ports which
> allows users to reserve ports for third-party applications.
> 
> The reserved ports will not be used by automatic port assignments
> (e.g. when calling connect() or bind() with port number 0). Explicit
> port allocation behavior is unchanged.
> 
> Changes from the previous version:
> - be more strict on accepted input (only comma separators, no spaces allowed)
> - add to the docs a paragraph about ip_local_port_range and
>   ip_local_reserved_ports relationship
> - fix a few corner cases with parsing
> 


Thanks for keeping working on this!

Then this version should be fine now.


> There are still some miss behaviors with regard to proc parsing in odd
> invalid cases (for "40000\0-40001" all is acknowledged but only 40000
> is accepted) but they are not easy to fix without changing the current
> "acknowledge how much we accepted" behavior.


I think this is the right behavior.

> 
> Because of that and because the same issues are present in the
> existing proc_dointvec code as well I don't think its worth holding
> the actual feature (port reservation) after such petty error recovery
> issues.
> 
> For the sake of discussion, I think Eric was right: the model we are
> using is messy, we should only accept all input or none. If we can
> (ABI implications) and you think its worth switching to this model I
> can give it a try in a future patch.
> 


Well, this depends, for things like "40000b", we should reject it,
since it is invalid, for "40000\0-40001", I think returning 5 is alright.

Thanks.

Re: [net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[Cong Wang]

David Miller wrote:
> Eric B., could you look over the first two patches (which touch the
> sysctl core) and give some review and ACK/NACK?
> 

ping Eric W. Biederman ... :)

Re: [net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[Eric W. Biederman]

Cong Wang <amwang@redhat.com> writes:

> David Miller wrote:
>> Eric B., could you look over the first two patches (which touch the
>> sysctl core) and give some review and ACK/NACK?
>>
>
> ping Eric W. Biederman ... :)

I have looked and it is not easy to tell by simple review if
correctness has been maintained in the proc cleanup patch.
Furthermore the code even after the cleanups still feels like code
that is trying too hard to do too much.


I think the example set by bitmap_parse_user in it's user interface is
a good example to follow when constructing bitmap helper functions.
Including having the actual parsing code should live in lib/bitmap.c

The users of bitmap_parse_user do something very nice.  They allocate
a temporary bitmap.  Parse the userspace value into the temporary
bitmap, and then move that new bitmap into the kernel data structures.
For your large bitmap this seems like the idea way to handle it.  That
guarantees no weird intermediate failure states, and really makes the
the bitmap feel like a single value.

I would add the restriction that the values in the list of ranges
always must be increasing, and in general restrict the set of accepted
values as much as possible.  If we don't accept it now we don't have
to worry about some userspace application relying on some unitended
side effect a few years into the future.


I think it is a serious bug that you clear the destination bitmap
in the middle of parsing it.  That will either open or close all
ports in the middle of parsing, and I can't see how that would
ever be a good thing.

Eric

Re: [net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[Octavian Purdila]

On Thursday 04 March 2010 21:14:07 you wrote:
> Cong Wang <amwang@redhat.com> writes:
> > David Miller wrote:
> >> Eric B., could you look over the first two patches (which touch the
> >> sysctl core) and give some review and ACK/NACK?
> >
> > ping Eric W. Biederman ... :)
> 
> I have looked and it is not easy to tell by simple review if
> correctness has been maintained in the proc cleanup patch.
> Furthermore the code even after the cleanups still feels like code
> that is trying too hard to do too much.
> 
> 
> I think the example set by bitmap_parse_user in it's user interface is
> a good example to follow when constructing bitmap helper functions.
> Including having the actual parsing code should live in lib/bitmap.c
> 
> The users of bitmap_parse_user do something very nice.  They allocate
> a temporary bitmap.  Parse the userspace value into the temporary
> bitmap, and then move that new bitmap into the kernel data structures.
> For your large bitmap this seems like the idea way to handle it.  That
> guarantees no weird intermediate failure states, and really makes the
> the bitmap feel like a single value.
> 
> I would add the restriction that the values in the list of ranges
> always must be increasing, and in general restrict the set of accepted
> values as much as possible.  If we don't accept it now we don't have
> to worry about some userspace application relying on some unitended
> side effect a few years into the future.
> 

Eric, thanks for taking the time to go over it again. I now do share you 
opinion that we need to be more atomic. How about this simple approach:

1. Allocate new kernel buffer for the text and copy the whole userspace buffer 
into it.
2. Allocate temporary buffer for bitmap.
3. Parse the kernel text buffer into the temp bitmap.
4. Copy the temp bitmap into the final bitmap.

This is simple and clean but it has the disadvantage of potentially allocating 
a large chunk of memory, although even in the case that all ports are going to 
be set the temporary buffer will not go over 390K, which is now not an issue 
anymore for kmalloc, right?

> I think it is a serious bug that you clear the destination bitmap
> in the middle of parsing it.  That will either open or close all
> ports in the middle of parsing, and I can't see how that would
> ever be a good thing.
> 

Even when doing the copy from the temp bitmap you still have some inconsistent 
bitmap state while copying. 

We could solve by replacing the old buffer with the new one + RCU.

Re: [net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[Eric W. Biederman]

Octavian Purdila <opurdila@ixiacom.com> writes:

> On Thursday 04 March 2010 21:14:07 you wrote:
>> Cong Wang <amwang@redhat.com> writes:
>> > David Miller wrote:
>> >> Eric B., could you look over the first two patches (which touch the
>> >> sysctl core) and give some review and ACK/NACK?
>> >
>> > ping Eric W. Biederman ... :)
>> 
>> I have looked and it is not easy to tell by simple review if
>> correctness has been maintained in the proc cleanup patch.
>> Furthermore the code even after the cleanups still feels like code
>> that is trying too hard to do too much.
>> 
>> 
>> I think the example set by bitmap_parse_user in it's user interface is
>> a good example to follow when constructing bitmap helper functions.
>> Including having the actual parsing code should live in lib/bitmap.c
>> 
>> The users of bitmap_parse_user do something very nice.  They allocate
>> a temporary bitmap.  Parse the userspace value into the temporary
>> bitmap, and then move that new bitmap into the kernel data structures.
>> For your large bitmap this seems like the idea way to handle it.  That
>> guarantees no weird intermediate failure states, and really makes the
>> the bitmap feel like a single value.
>> 
>> I would add the restriction that the values in the list of ranges
>> always must be increasing, and in general restrict the set of accepted
>> values as much as possible.  If we don't accept it now we don't have
>> to worry about some userspace application relying on some unitended
>> side effect a few years into the future.
>> 
>
> Eric, thanks for taking the time to go over it again. I now do share you 
> opinion that we need to be more atomic. How about this simple approach:
>
> 1. Allocate new kernel buffer for the text and copy the whole userspace buffer 
> into it.
> 2. Allocate temporary buffer for bitmap.
> 3. Parse the kernel text buffer into the temp bitmap.
> 4. Copy the temp bitmap into the final bitmap.
>
> This is simple and clean but it has the disadvantage of potentially allocating 
> a large chunk of memory, although even in the case that all ports are going to 
> be set the temporary buffer will not go over 390K, which is now not an issue 
> anymore for kmalloc, right?

More than page size will always be an issue when memory is
sufficiently fragmented.  I expect we can do just about as simply
with a small sliding window. Perhaps 50 characters.

However that might not be worth worrying about.  Anything set by
a human being and anything we expect in practice is going to be
much shorter.

>> I think it is a serious bug that you clear the destination bitmap
>> in the middle of parsing it.  That will either open or close all
>> ports in the middle of parsing, and I can't see how that would
>> ever be a good thing.
>> 
>
> Even when doing the copy from the temp bitmap you still have some inconsistent 
> bitmap state while copying. 
>
> We could solve by replacing the old buffer with the new one + RCU.

True.

I was thinking a simple pass through that updated it a bit at a time
(if it was different), but rcu or some other form of locking would be
even more consistent.  The joy with splitting the parser for the rest
of the sysctl code is that this is a separate decision that can be made
to accommodate the specific user.

Eric

Re: [net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[Cong Wang]

Eric W. Biederman wrote:
> 
> I would add the restriction that the values in the list of ranges
> always must be increasing, and in general restrict the set of accepted
> values as much as possible.  If we don't accept it now we don't have
> to worry about some userspace application relying on some unitended
> side effect a few years into the future.

I don't think this is good.

Suppose that when I just want to add one port into the list and keep the
original ones, I want to do this:

orig=$(cat ip_local_reserved_ports)
new_list="$orig, $new_one"
echo "$new_list" > ip_local_reserved_ports

If we add this restriction, the above could be failed if the new port
is lower than the original ones. This will be not convenient.

> 
> 
> I think it is a serious bug that you clear the destination bitmap
> in the middle of parsing it.  That will either open or close all
> ports in the middle of parsing, and I can't see how that would
> ever be a good thing.
> 

Agreed.

By the way, Octavian, any new updates?

Re: [net-next PATCH v6 0/3] net: reserve ports for applications using fixed port numbers

[Octavian Purdila]

On Wednesday 10 March 2010 11:23:15 you wrote:
> Eric W. Biederman wrote:
> > I would add the restriction that the values in the list of ranges
> > always must be increasing, and in general restrict the set of accepted
> > values as much as possible.  If we don't accept it now we don't have
> > to worry about some userspace application relying on some unitended
> > side effect a few years into the future.
> 
> I don't think this is good.
> 
> Suppose that when I just want to add one port into the list and keep the
> original ones, I want to do this:
> 
> orig=$(cat ip_local_reserved_ports)
> new_list="$orig, $new_one"
> echo "$new_list" > ip_local_reserved_ports
> 
> If we add this restriction, the above could be failed if the new port
> is lower than the original ones. This will be not convenient.
> 
> > I think it is a serious bug that you clear the destination bitmap
> > in the middle of parsing it.  That will either open or close all
> > ports in the middle of parsing, and I can't see how that would
> > ever be a good thing.
> 
> Agreed.
> 
> By the way, Octavian, any new updates?
> 

Sorry, didn't got time to work on this lately, but I will submit a new version 
I hope end of this week to address Eric's comments.