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[204.195.123.141]) by smtp.gmail.com with ESMTPSA id f7-20020a170902ab8700b001c76fcccee8sm3787356plr.156.2023.11.09.09.34.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Nov 2023 09:34:27 -0800 (PST) From: Stephen Hemminger To: dev@dpdk.org Cc: Stephen Hemminger , =?UTF-8?q?Morten=20Br=C3=B8rup?= , Reshma Pattan Subject: [PATCH v4 4/5] pcapng: avoid using alloca() Date: Thu, 9 Nov 2023 09:34:11 -0800 Message-Id: <20231109173412.108093-5-stephen@networkplumber.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231109173412.108093-1-stephen@networkplumber.org> References: <20230921042349.104150-1-stephen@networkplumber.org> <20231109173412.108093-1-stephen@networkplumber.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.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 Acked-by: Morten Brørup --- 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; -- 2.39.2