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From: Stephen Hemminger <stephen@networkplumber.org>
To: dev@dpdk.org
Cc: "Stephen Hemminger" <stephen@networkplumber.org>,
	"Morten Brørup" <mb@smartsharesystems.com>,
	"Reshma Pattan" <reshma.pattan@intel.com>
Subject: [PATCH v7 4/5] pcapng: avoid using alloca()
Date: Fri, 17 Nov 2023 08:35:58 -0800	[thread overview]
Message-ID: <20231117163729.243188-5-stephen@networkplumber.org> (raw)
In-Reply-To: <20231117163729.243188-1-stephen@networkplumber.org>

The function alloca() like VLA's has problems if the caller
passes a large value. Instead use a fixed size buffer (2K)
which will be more than sufficient for the info related blocks
in the file. Add bounds checks as well.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
---
 lib/pcapng/rte_pcapng.c | 37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/lib/pcapng/rte_pcapng.c b/lib/pcapng/rte_pcapng.c
index 13fd2b97fb80..f74ec939a9f8 100644
--- a/lib/pcapng/rte_pcapng.c
+++ b/lib/pcapng/rte_pcapng.c
@@ -33,6 +33,9 @@
 /* conversion from DPDK speed to PCAPNG */
 #define PCAPNG_MBPS_SPEED 1000000ull
 
+/* upper bound for section, stats and interface blocks */
+#define PCAPNG_BLKSIZ	2048
+
 /* Format of the capture file handle */
 struct rte_pcapng {
 	int  outfd;		/* output file */
@@ -140,9 +143,8 @@ pcapng_section_block(rte_pcapng_t *self,
 {
 	struct pcapng_section_header *hdr;
 	struct pcapng_option *opt;
-	void *buf;
+	uint8_t buf[PCAPNG_BLKSIZ];
 	uint32_t len;
-	ssize_t cc;
 
 	len = sizeof(*hdr);
 	if (hw)
@@ -158,8 +160,7 @@ pcapng_section_block(rte_pcapng_t *self,
 	len += pcapng_optlen(0);
 	len += sizeof(uint32_t);
 
-	buf = calloc(1, len);
-	if (!buf)
+	if (len > sizeof(buf))
 		return -1;
 
 	hdr = (struct pcapng_section_header *)buf;
@@ -193,10 +194,7 @@ pcapng_section_block(rte_pcapng_t *self,
 	/* clone block_length after option */
 	memcpy(opt, &hdr->block_length, sizeof(uint32_t));
 
-	cc = write(self->outfd, buf, len);
-	free(buf);
-
-	return cc;
+	return write(self->outfd, buf, len);
 }
 
 /* Write an interface block for a DPDK port */
@@ -213,7 +211,7 @@ rte_pcapng_add_interface(rte_pcapng_t *self, uint16_t port,
 	struct pcapng_option *opt;
 	const uint8_t tsresol = 9;	/* nanosecond resolution */
 	uint32_t len;
-	void *buf;
+	uint8_t buf[PCAPNG_BLKSIZ];
 	char ifname_buf[IF_NAMESIZE];
 	char ifhw[256];
 	uint64_t speed = 0;
@@ -267,8 +265,7 @@ rte_pcapng_add_interface(rte_pcapng_t *self, uint16_t port,
 	len += pcapng_optlen(0);
 	len += sizeof(uint32_t);
 
-	buf = alloca(len);
-	if (!buf)
+	if (len > sizeof(buf))
 		return -1;
 
 	hdr = (struct pcapng_interface_block *)buf;
@@ -296,17 +293,16 @@ rte_pcapng_add_interface(rte_pcapng_t *self, uint16_t port,
 		opt = pcapng_add_option(opt, PCAPNG_IFB_HARDWARE,
 					 ifhw, strlen(ifhw));
 	if (filter) {
-		/* Encoding is that the first octet indicates string vs BPF */
 		size_t len;
-		char *buf;
 
 		len = strlen(filter) + 1;
-		buf = alloca(len);
-		*buf = '\0';
-		memcpy(buf + 1, filter, len);
+		opt->code = PCAPNG_IFB_FILTER;
+		opt->length = len;
+		/* Encoding is that the first octet indicates string vs BPF */
+		opt->data[0] = 0;
+		memcpy(opt->data + 1, filter, strlen(filter));
 
-		opt = pcapng_add_option(opt, PCAPNG_IFB_FILTER,
-					buf, len);
+		opt = (struct pcapng_option *)((uint8_t *)opt + pcapng_optlen(len));
 	}
 
 	opt = pcapng_add_option(opt, PCAPNG_OPT_END, NULL, 0);
@@ -333,7 +329,7 @@ rte_pcapng_write_stats(rte_pcapng_t *self, uint16_t port_id,
 	uint64_t start_time = self->offset_ns;
 	uint64_t sample_time;
 	uint32_t optlen, len;
-	uint8_t *buf;
+	uint8_t buf[PCAPNG_BLKSIZ];
 
 	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
 
@@ -353,8 +349,7 @@ rte_pcapng_write_stats(rte_pcapng_t *self, uint16_t port_id,
 		optlen += pcapng_optlen(0);
 
 	len = sizeof(*hdr) + optlen + sizeof(uint32_t);
-	buf = alloca(len);
-	if (buf == NULL)
+	if (len > sizeof(buf))
 		return -1;
 
 	hdr = (struct pcapng_statistics *)buf;
-- 
2.42.0


  parent reply	other threads:[~2023-11-17 16:38 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-21  4:23 [PATCH 0/4] pcapng fixes Stephen Hemminger
2023-09-21  4:23 ` [PATCH 1/4] pdump: fix setting rte_errno on mp error Stephen Hemminger
2023-09-21  4:23 ` [PATCH 2/4] dumpcap: allow multiple invocations Stephen Hemminger
2023-09-21  6:22   ` Morten Brørup
2023-09-21  7:10     ` Isaac Boukris
2023-11-07  2:34     ` Stephen Hemminger
2023-09-21  4:23 ` [PATCH 3/4] pcapng: change timestamp argument to write_stats Stephen Hemminger
2023-09-21  4:23 ` [PATCH 4/4] pcapng: move timestamp calculation into pdump Stephen Hemminger
2023-10-02  8:15   ` David Marchand
2023-10-04 17:13     ` Stephen Hemminger
2023-10-06  9:10       ` David Marchand
2023-10-06 14:59         ` Kevin Traynor
2023-10-05 23:06 ` [PATCH v2 0/4] dumpcap and pcapng fixes Stephen Hemminger
2023-10-05 23:06   ` [PATCH v2 1/4] pdump: fix setting rte_errno on mp error Stephen Hemminger
2023-10-05 23:06   ` [PATCH v2 2/4] dumpcap: allow multiple invocations Stephen Hemminger
2023-10-05 23:06   ` [PATCH v2 3/4] pcapng: modify timestamp calculation Stephen Hemminger
2023-10-05 23:06   ` [PATCH v2 4/4] test: cleanups to pcapng test Stephen Hemminger
2023-11-08 18:35 ` [PATCH v3 0/5] dumpcap and pcapng fixes Stephen Hemminger
2023-11-08 18:35   ` [PATCH v3 1/5] pdump: fix setting rte_errno on mp error Stephen Hemminger
2023-11-09  7:34     ` Morten Brørup
2023-11-08 18:35   ` [PATCH v3 2/5] dumpcap: allow multiple invocations Stephen Hemminger
2023-11-09  7:50     ` Morten Brørup
2023-11-09 15:40       ` Stephen Hemminger
2023-11-09 16:00         ` Morten Brørup
2023-11-09 17:16       ` Stephen Hemminger
2023-11-09 18:22         ` Morten Brørup
2023-11-08 18:35   ` [PATCH v3 3/5] pcapng: modify timestamp calculation Stephen Hemminger
2023-11-09  7:57     ` Morten Brørup
2023-11-08 18:35   ` [PATCH v3 4/5] pcapng: avoid using alloca() Stephen Hemminger
2023-11-09  8:21     ` Morten Brørup
2023-11-09 15:44       ` Stephen Hemminger
2023-11-09 16:25         ` Morten Brørup
2023-11-08 18:35   ` [PATCH v3 5/5] test: cleanups to pcapng test Stephen Hemminger
2023-11-09 17:34 ` [PATCH v4 0/5] dumpcap and pcapng fixes Stephen Hemminger
2023-11-09 17:34   ` [PATCH v4 1/5] pdump: fix setting rte_errno on mp error Stephen Hemminger
2023-11-09 17:34   ` [PATCH v4 2/5] dumpcap: allow multiple invocations Stephen Hemminger
2023-11-09 18:30     ` Morten Brørup
2023-11-09 17:34   ` [PATCH v4 3/5] pcapng: modify timestamp calculation Stephen Hemminger
2023-11-09 17:34   ` [PATCH v4 4/5] pcapng: avoid using alloca() Stephen Hemminger
2023-11-09 17:34   ` [PATCH v4 5/5] test: cleanups to pcapng test Stephen Hemminger
2023-11-09 19:45 ` [PATCH v5 0/5] dumpcap and pcapng fixes Stephen Hemminger
2023-11-09 19:45   ` [PATCH v5 1/5] pdump: fix setting rte_errno on mp error Stephen Hemminger
2023-11-09 19:45   ` [PATCH v5 2/5] dumpcap: allow multiple invocations Stephen Hemminger
2023-11-09 20:09     ` Morten Brørup
2023-11-09 19:45   ` [PATCH v5 3/5] pcapng: modify timestamp calculation Stephen Hemminger
2023-11-12 14:22     ` Thomas Monjalon
2023-11-09 19:45   ` [PATCH v5 4/5] pcapng: avoid using alloca() Stephen Hemminger
2023-11-09 19:45   ` [PATCH v5 5/5] test: cleanups to pcapng test Stephen Hemminger
2023-11-13 16:15 ` [PATCH v6 0/5] dumpcap and pcapng fixes Stephen Hemminger
2023-11-13 16:15   ` [PATCH v6 1/5] pdump: fix setting rte_errno on mp error Stephen Hemminger
2023-11-13 16:15   ` [PATCH v6 2/5] dumpcap: allow multiple invocations Stephen Hemminger
2023-11-13 16:15   ` [PATCH v6 3/5] pcapng: modify timestamp calculation Stephen Hemminger
2023-11-13 16:15   ` [PATCH v6 4/5] pcapng: avoid using alloca() Stephen Hemminger
2023-11-13 16:15   ` [PATCH v6 5/5] test: cleanups to pcapng test Stephen Hemminger
2023-11-17 16:35 ` [PATCH v7 0/5] dumpcap and pcapng fixes Stephen Hemminger
2023-11-17 16:35   ` [PATCH v7 1/5] pdump: fix setting rte_errno on mp error Stephen Hemminger
2023-11-17 16:35   ` [PATCH v7 2/5] dumpcap: allow multiple invocations Stephen Hemminger
2023-11-17 16:35   ` [PATCH v7 3/5] pcapng: modify timestamp calculation Stephen Hemminger
2023-11-17 16:35   ` Stephen Hemminger [this message]
2023-11-17 16:35   ` [PATCH v7 5/5] test: cleanups to pcapng test Stephen Hemminger
2023-11-22 22:42   ` [PATCH v7 0/5] dumpcap and pcapng fixes Thomas Monjalon

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