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From d062793e7aebde3ffee796dfd4180716632ae444 Mon Sep 17 00:00:00 2001
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From: Jean Delvare <jdelvare@suse.de>
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Date: Wed, 8 Nov 2017 22:17:43 +0100
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Subject: [PATCH 2/3] tools: i2cbusses: Check the return value of snprintf
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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It's very unlikely that these paths will ever be truncated, but
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better safe than sorry.
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Suggested by Uwe Kleine-K├Ânig.
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---
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 tools/i2cbusses.c | 34 ++++++++++++++++++++++++++++------
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 1 file changed, 28 insertions(+), 6 deletions(-)
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diff --git a/tools/i2cbusses.c b/tools/i2cbusses.c
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index cb78cc7..41f5b6b 100644
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--- a/tools/i2cbusses.c
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+++ b/tools/i2cbusses.c
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@@ -137,7 +137,7 @@ struct i2c_adap *gather_i2c_busses(void)
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 	FILE *f;
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 	char fstype[NAME_MAX], sysfs[NAME_MAX], n[NAME_MAX];
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 	int foundsysfs = 0;
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-	int count=0;
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+	int len, count = 0;
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 	struct i2c_adap *adapters;
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 	adapters = calloc(BUNCH, sizeof(struct i2c_adap));
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@@ -220,18 +220,32 @@ struct i2c_adap *gather_i2c_busses(void)
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 		/* this should work for kernels 2.6.5 or higher and */
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 		/* is preferred because is unambiguous */
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-		snprintf(n, NAME_MAX, "%s/%s/name", sysfs, de->d_name);
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+		len = snprintf(n, NAME_MAX, "%s/%s/name", sysfs, de->d_name);
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+		if (len >= NAME_MAX) {
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+			fprintf(stderr, "%s: path truncated\n", n);
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+			continue;
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+		}
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 		f = fopen(n, "r");
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 		/* this seems to work for ISA */
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 		if(f == NULL) {
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-			snprintf(n, NAME_MAX, "%s/%s/device/name", sysfs, de->d_name);
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+			len = snprintf(n, NAME_MAX, "%s/%s/device/name", sysfs,
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+				       de->d_name);
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+			if (len >= NAME_MAX) {
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+				fprintf(stderr, "%s: path truncated\n", n);
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+				continue;
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+			}
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 			f = fopen(n, "r");
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 		}
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 		/* non-ISA is much harder */
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 		/* and this won't find the correct bus name if a driver
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 		   has more than one bus */
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 		if(f == NULL) {
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-			snprintf(n, NAME_MAX, "%s/%s/device", sysfs, de->d_name);
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+			len = snprintf(n, NAME_MAX, "%s/%s/device", sysfs,
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+				       de->d_name);
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+			if (len >= NAME_MAX) {
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+				fprintf(stderr, "%s: path truncated\n", n);
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+				continue;
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+			}
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 			if(!(ddir = opendir(n)))
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 				continue;
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 			while ((dde = readdir(ddir)) != NULL) {
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@@ -240,8 +254,16 @@ struct i2c_adap *gather_i2c_busses(void)
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 				if (!strcmp(dde->d_name, ".."))
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 					continue;
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 				if ((!strncmp(dde->d_name, "i2c-", 4))) {
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-					snprintf(n, NAME_MAX, "%s/%s/device/%s/name",
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-						 sysfs, de->d_name, dde->d_name);
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+					len = snprintf(n, NAME_MAX,
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+						       "%s/%s/device/%s/name",
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+						       sysfs, de->d_name,
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+						       dde->d_name);
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+					if (len >= NAME_MAX) {
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+						fprintf(stderr,
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+							"%s: path truncated\n",
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+							n);
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+						continue;
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+					}
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 					if((f = fopen(n, "r")))
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 						goto found;
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 				}
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-- 
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2.14.3
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