From: guy <guy>
Date: Sat, 28 Oct 2000 00:01:26 +0000 (+0000)
Subject: When attaching a "bpf_program" to a "pcap_t" to use as a userland
X-Git-Tag: libpcap-0.6.1~52
X-Git-Url: https://git.tcpdump.org/libpcap/commitdiff_plain/82547471f79c2cf4a9943a222d006edc4add2d76?ds=sidebyside

When attaching a "bpf_program" to a "pcap_t" to use as a userland
filter, always attach a copy, as "pcap-linux.c" does; that way, after a
program uses "pcap_setfilter()", it can safely use "pcap_freecode()" to
free up the BPF instructions allocated by "pcap_compile()".  Also,
always free it up when the "pcap_t" is closed.

Get rid of the "pcap_t *" argument to "pcap_freecode()", as it's not
necessary.

Document "pcap_freecode()", for the benefit of programs that might
repeatedly compile filter programs and attach them, so that they can
free them up after attaching them and avoid leaking memory for them.
---

diff --git a/gencode.c b/gencode.c
index 0ff11fc9..12706b65 100644
--- a/gencode.c
+++ b/gencode.c
@@ -21,7 +21,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.125 2000-10-25 07:28:22 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.126 2000-10-28 00:01:26 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -377,7 +377,7 @@ pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
  * in it.
  */
 void
-pcap_freecode(pcap_t *p, struct bpf_program *program)
+pcap_freecode(struct bpf_program *program)
 {
 	program->bf_len = 0;
 	if (program->bf_insns != NULL) {
diff --git a/gencode.h b/gencode.h
index 8feffb06..96c2bdee 100644
--- a/gencode.h
+++ b/gencode.h
@@ -18,7 +18,7 @@
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * @(#) $Header: /tcpdump/master/libpcap/gencode.h,v 1.42 2000-10-22 04:15:56 guy Exp $ (LBL)
+ * @(#) $Header: /tcpdump/master/libpcap/gencode.h,v 1.43 2000-10-28 00:01:27 guy Exp $ (LBL)
  */
 
 /* Address qualifiers. */
@@ -186,6 +186,7 @@ void finish_parse(struct block *);
 char *sdup(const char *);
 
 struct bpf_insn *icode_to_fcode(struct block *, int *);
+int install_bpf_program(pcap_t *, struct bpf_program *);
 int pcap_parse(void);
 void lex_init(char *);
 void lex_cleanup(void);
diff --git a/optimize.c b/optimize.c
index c39f8992..fe2c2cae 100644
--- a/optimize.c
+++ b/optimize.c
@@ -22,7 +22,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/optimize.c,v 1.64 2000-09-06 07:40:03 itojun Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/optimize.c,v 1.65 2000-10-28 00:01:27 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -36,6 +36,8 @@ static const char rcsid[] =
 #include <stdlib.h>
 #include <memory.h>
 
+#include <errno.h>
+
 #include "pcap-int.h"
 
 #include "gencode.h"
@@ -2077,6 +2079,36 @@ icode_to_fcode(root, lenp)
 	return fp;
 }
 
+/*
+ * Make a copy of a BPF program and put it in the "fcode" member of
+ * a "pcap_t".
+ *
+ * If we fail to allocate memory for the copy, fill in the "errbuf"
+ * member of the "pcap_t" with an error message, and return -1;
+ * otherwise, return 0.
+ */
+int
+install_bpf_program(pcap_t *p, struct bpf_program *fp)
+{
+	size_t prog_size;
+
+	/*
+	 * Free up any already installed program.
+	 */
+	pcap_freecode(&p->fcode);
+
+	prog_size = sizeof(*fp->bf_insns) * fp->bf_len;
+	p->fcode.bf_len = fp->bf_len;
+	p->fcode.bf_insns = (struct bpf_insn *)malloc(prog_size);
+	if (p->fcode.bf_insns == NULL) {
+		snprintf(p->errbuf, sizeof(p->errbuf),
+			 "malloc: %s", pcap_strerror(errno));
+		return (-1);
+	}
+	memcpy(p->fcode.bf_insns, fp->bf_insns, prog_size);
+	return (0);
+}
+
 #ifdef BDEBUG
 static void
 opt_dump(root)
diff --git a/pcap-bpf.c b/pcap-bpf.c
index a0d89ed6..e8a2d404 100644
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -20,7 +20,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.43 2000-10-12 03:53:58 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.44 2000-10-28 00:01:28 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -372,11 +372,13 @@ pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 	 * compatible with some of kernel BPF code (for example BSD/OS 3.1).
 	 * Take a safer side for now.
 	 */
-	if (no_optimize)
-		p->fcode = *fp;
-	else if (p->sf.rfile != NULL)
-		p->fcode = *fp;
-	else if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) < 0) {
+	if (no_optimize) {
+		if (install_bpf_program(p, fp) < 0)
+			return (-1);
+	} else if (p->sf.rfile != NULL) {
+		if (install_bpf_program(p, fp) < 0)
+			return (-1);
+	} else if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) < 0) {
 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s",
 		    pcap_strerror(errno));
 		return (-1);
diff --git a/pcap-dlpi.c b/pcap-dlpi.c
index 608c8a23..153896a0 100644
--- a/pcap-dlpi.c
+++ b/pcap-dlpi.c
@@ -38,7 +38,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-dlpi.c,v 1.61 2000-10-12 03:53:58 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-dlpi.c,v 1.62 2000-10-28 00:01:28 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -555,7 +555,8 @@ int
 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 {
 
-	p->fcode = *fp;
+	if (install_bpf_program(p, fp) < 0)
+		return (-1);
 	return (0);
 }
 
diff --git a/pcap-linux.c b/pcap-linux.c
index d5e4f53d..f3a636f9 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -26,7 +26,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.38 2000-10-25 07:46:50 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.39 2000-10-28 00:01:29 guy Exp $ (LBL)";
 #endif
 
 /*
@@ -432,22 +432,13 @@ pcap_setfilter(pcap_t *handle, struct bpf_program *filter)
 		return -1;
 	}
 
-	/* Free old filter code if existing */
-
-	pcap_freecode(handle, &handle->fcode);
-
 	/* Make our private copy of the filter */
 
-	handle->fcode.bf_len   = filter->bf_len;
-	handle->fcode.bf_insns = 
-		malloc(filter->bf_len * sizeof(*filter->bf_insns));
-	if (handle->fcode.bf_insns == NULL) {
+	if (install_bpf_program(handle, filter) < 0) {
 		snprintf(handle->errbuf, sizeof(handle->errbuf),
 			 "malloc: %s", pcap_strerror(errno));
 		return -1;
-	} 
-	memcpy(handle->fcode.bf_insns, filter->bf_insns, 
-	       filter->bf_len * sizeof(*filter->bf_insns));
+	}
 
 	/* 
 	 * Run user level packet filter by default. Will be overriden if 
diff --git a/pcap-nit.c b/pcap-nit.c
index c15704b4..524d8c38 100644
--- a/pcap-nit.c
+++ b/pcap-nit.c
@@ -20,7 +20,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-nit.c,v 1.38 2000-10-12 03:54:00 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-nit.c,v 1.39 2000-10-28 00:01:29 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -245,6 +245,7 @@ int
 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 {
 
-	p->fcode = *fp;
+	if (install_bpf_program(p, fp) < 0)
+		return (-1);
 	return (0);
 }
diff --git a/pcap-null.c b/pcap-null.c
index 588c4d32..e952c988 100644
--- a/pcap-null.c
+++ b/pcap-null.c
@@ -20,7 +20,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-null.c,v 1.12 2000-07-11 00:37:06 assar Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-null.c,v 1.13 2000-10-28 00:01:29 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -68,6 +68,7 @@ pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 		    "pcap_setfilter: %s", nosup);
 		return (-1);
 	}
-	p->fcode = *fp;
+	if (install_bpf_program(p, fp) < 0)
+		return (-1);
 	return (0);
 }
diff --git a/pcap-pf.c b/pcap-pf.c
index 58e85269..6a68a504 100644
--- a/pcap-pf.c
+++ b/pcap-pf.c
@@ -24,7 +24,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-pf.c,v 1.61 2000-10-12 03:54:00 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-pf.c,v 1.62 2000-10-28 00:01:30 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -347,8 +347,10 @@ pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 			/* don't give up, just be inefficient */
 			p->md.use_bpf = 0;
 		}
-	} else
-		p->fcode = *fp;
+	} else {
+		if (install_bpf_program(p, fp) < 0)
+			return (-1);
+	}
 
 	/*XXX this goes in tcpdump*/
 	if (p->md.use_bpf)
diff --git a/pcap-snit.c b/pcap-snit.c
index e20a28ae..47818e4f 100644
--- a/pcap-snit.c
+++ b/pcap-snit.c
@@ -25,7 +25,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-snit.c,v 1.53 2000-10-12 03:54:00 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-snit.c,v 1.54 2000-10-28 00:01:30 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -302,6 +302,7 @@ int
 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 {
 
-	p->fcode = *fp;
+	if (install_bpf_program(p, fp) < 0)
+		return (-1);
 	return (0);
 }
diff --git a/pcap-snoop.c b/pcap-snoop.c
index 7268500c..82e51c4f 100644
--- a/pcap-snoop.c
+++ b/pcap-snoop.c
@@ -20,7 +20,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-snoop.c,v 1.29 2000-10-12 03:54:01 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-snoop.c,v 1.30 2000-10-28 00:01:30 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -274,6 +274,7 @@ int
 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 {
 
-	p->fcode = *fp;
+	if (install_bpf_program(p, fp) < 0)
+		return (-1);
 	return (0);
 }
diff --git a/pcap.3 b/pcap.3
index 18bcb4ad..2dc98ea7 100644
--- a/pcap.3
+++ b/pcap.3
@@ -1,4 +1,4 @@
-.\" @(#) $Header: /tcpdump/master/libpcap/Attic/pcap.3,v 1.12 2000-10-22 02:21:34 guy Exp $
+.\" @(#) $Header: /tcpdump/master/libpcap/Attic/pcap.3,v 1.13 2000-10-28 00:01:31 guy Exp $
 .\"
 .\" Copyright (c) 1994, 1996, 1997
 .\"	The Regents of the University of California.  All rights reserved.
@@ -62,6 +62,7 @@ int pcap_compile(pcap_t *p, struct bpf_program *fp,
 .ti +8
 char *str, int optimize, bpf_u_int32 netmask)
 int pcap_setfilter(pcap_t *p, struct bpf_program *fp)
+void pcap_freecode(struct bpf_program *);
 .ft
 .LP
 .ft B
@@ -256,14 +257,14 @@ is similar to
 .B pcap_compile()
 except that instead of passing a pcap structure, one passes the
 snaplen and linktype explicitly.  It is intended to be used for
-compiling filters for direct bpf usage, without necessarily having
+compiling filters for direct BPF usage, without necessarily having
 called
 .BR pcap_open() .
 .PP
 .B pcap_setfilter()
 is used to specify a filter program.
 .I fp
-is a pointer to an array of
+is a pointer to a
 .I bpf_program
 struct, usually the result of a call to
 .BR pcap_compile() .
@@ -272,6 +273,15 @@ is returned on failure;
 .B 0
 is returned on success.
 .PP
+.B pcap_freecode()
+is used to free up allocated memory pointed to by a
+.I bpf_program
+struct generated by
+.B pcap_compile()
+when that BPF program is no longer needed, for example after it
+has been made the filter program for a pcap structure by a call to
+.BR pcap_setfilter() .
+.PP
 .B pcap_loop()
 is similar to
 .B pcap_dispatch()
diff --git a/pcap.c b/pcap.c
index 72caa6fb..fd9dc9f1 100644
--- a/pcap.c
+++ b/pcap.c
@@ -33,7 +33,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.34 2000-10-25 06:59:10 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.35 2000-10-28 00:01:31 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -219,8 +219,8 @@ pcap_close(pcap_t *p)
 #ifdef linux
 	if (p->md.device != NULL)
 		free(p->md.device);
-	pcap_freecode(p, &p->fcode);
 #endif
 	
+	pcap_freecode(&p->fcode);
 	free(p);
 }
diff --git a/pcap.h b/pcap.h
index 57b7bc9c..7d62728f 100644
--- a/pcap.h
+++ b/pcap.h
@@ -30,7 +30,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * @(#) $Header: /tcpdump/master/libpcap/pcap.h,v 1.30 2000-10-25 06:59:10 guy Exp $ (LBL)
+ * @(#) $Header: /tcpdump/master/libpcap/pcap.h,v 1.31 2000-10-28 00:01:31 guy Exp $ (LBL)
  */
 
 #ifndef lib_pcap_h
@@ -150,7 +150,7 @@ int	pcap_compile(pcap_t *, struct bpf_program *, char *, int,
 	    bpf_u_int32);
 int	pcap_compile_nopcap(int, int, struct bpf_program *,
 	    char *, int, bpf_u_int32);
-void	pcap_freecode(pcap_t *, struct bpf_program *);
+void	pcap_freecode(struct bpf_program *);
 int	pcap_datalink(pcap_t *);
 int	pcap_snapshot(pcap_t *);
 int	pcap_is_swapped(pcap_t *);