Sent too soon.  The suggestions don't guarantee null termination.  Refined, below. (Sorry for the noise.)

On 04/21/2017 08:33 AM, Paul Clarke wrote:

On 04/21/2017 07:33 AM, Naveen N. Rao wrote:

quoted

Convert usage of strchr()/strncpy()/strncat() to
strnchr()/memcpy()/strlcat() for simpler and safer string manipulation.

quoted

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 97b5eed1f76d..c73fb6e3b43f 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c

@@ -65,28 +65,27 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
 	char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN];
 	const char *modsym;
 	bool dot_appended = false;
-	if ((modsym = strchr(name, ':')) != NULL) {
+	if ((modsym = strnchr(name, ':', MODULE_NAME_LEN)) != NULL) {
 		modsym++;
 		if (*modsym != '\0' && *modsym != '.') {
 			/* Convert to <module:.symbol> */
-			strncpy(dot_name, name, modsym - name);
+			memcpy(dot_name, name, modsym - name);
 			dot_name[modsym - name] = '.';
 			dot_name[modsym - name + 1] = '\0';
-			strncat(dot_name, modsym,
-				sizeof(dot_name) - (modsym - name) - 2);
+			strlcat(dot_name, modsym, sizeof(dot_name));

Would it be more efficient here to replace this:
--
dot_name[modsym - name + 1] = '\0';
strlcat(dot_name, modsym, sizeof(dot_name));
--

with this:
strncpy(&dot_name[modsym - name + 1], modsym, KSYM_NAME_LEN);

keep the null termination, and just adjust the starting point for strlcat:
--
dot_name[modsym - name + 1] = '\0';
strlcat(&dot_name[modsym - name + 1], modsym, KSYM_NAME_LEN);
--

(So you aren't rescanning dot_name to find the end, when you already know the end position?)

quoted

 			dot_appended = true;
 		} else {
 			dot_name[0] = '\0';
-			strncat(dot_name, name, sizeof(dot_name) - 1);
+			strlcat(dot_name, name, sizeof(dot_name));

and here do:
strncpy(dot_name, name, sizeof(dot_name));

(and remove the null termination immediately above)

nevermind.  :-)

quoted

 		}
 	} else if (name[0] != '.') {
 		dot_name[0] = '.';
 		dot_name[1] = '\0';
-		strncat(dot_name, name, KSYM_NAME_LEN - 2);
+		strlcat(dot_name, name, sizeof(dot_name));

and here do:
strncpy(&dot_name[1], name, sizeof(dot_name));

(and remove the null termination immediately above)

nevermind.  :-)

quoted

 		dot_appended = true;
 	} else {
 		dot_name[0] = '\0';
-		strncat(dot_name, name, KSYM_NAME_LEN - 1);
+		strlcat(dot_name, name, sizeof(dot_name));

and here do:
strncpy(dot_name, name, sizeof(dot_name));

(and remove the null termination immediately above)

quoted

 	}

nevermind.  :-)

PC