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[20/20] s390/watchdog: Manual replacement of the deprecated strlcpy() with return values

Message ID 20210222151231.22572-21-romain.perier@gmail.com
State New
Headers show
Series Manual replacement of all strlcpy in favor of strscpy | expand

Commit Message

Romain Perier Feb. 22, 2021, 3:12 p.m. UTC 
The strlcpy() reads the entire source buffer first, it is dangerous if
the source buffer lenght is unbounded or possibility non NULL-terminated.
It can lead to linear read overflows, crashes, etc...

As recommended in the deprecated interfaces [1], it should be replaced
by strscpy.

This commit replaces all calls to strlcpy that handle the return values
by the corresponding strscpy calls with new handling of the return
values (as it is quite different between the two functions).

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy

Signed-off-by: Romain Perier <romain.perier@gmail.com>
---
 drivers/watchdog/diag288_wdt.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/watchdog/diag288_wdt.c b/drivers/watchdog/diag288_wdt.c
index aafc8d98bf9f..5703f35dd0b7 100644
--- a/drivers/watchdog/diag288_wdt.c
+++ b/drivers/watchdog/diag288_wdt.c
@@ -111,7 +111,7 @@  static unsigned long wdt_status;
 static int wdt_start(struct watchdog_device *dev)
 {
 	char *ebc_cmd;
-	size_t len;
+	ssize_t len;
 	int ret;
 	unsigned int func;
 
@@ -126,7 +126,9 @@  static int wdt_start(struct watchdog_device *dev)
 			clear_bit(DIAG_WDOG_BUSY, &wdt_status);
 			return -ENOMEM;
 		}
-		len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
+		len = strscpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
+		if (len == -E2BIG)
+			return -E2BIG;
 		ASCEBC(ebc_cmd, MAX_CMDLEN);
 		EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
 
@@ -163,7 +165,7 @@  static int wdt_stop(struct watchdog_device *dev)
 static int wdt_ping(struct watchdog_device *dev)
 {
 	char *ebc_cmd;
-	size_t len;
+	ssize_t len;
 	int ret;
 	unsigned int func;
 
@@ -173,7 +175,9 @@  static int wdt_ping(struct watchdog_device *dev)
 		ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
 		if (!ebc_cmd)
 			return -ENOMEM;
-		len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
+		len = strscpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
+		if (len == -E2BIG)
+			return -E2BIG;
 		ASCEBC(ebc_cmd, MAX_CMDLEN);
 		EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);