In a subsequent patch we'd like to have something like a strscpy_pad()
implementation usable in prom_init.c.
Currently we have a strcpy() implementation with only one caller, so
convert it into strscpy_pad() and update the caller.
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
---
arch/powerpc/kernel/prom_init.c | 30 ++++++++++++++++++++++++------
1 file changed, 24 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 523b31685c4c..c18d55f8b951 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -242,13 +242,31 @@ static int __init prom_strcmp(const char *cs, const char
*ct)
return 0;
}
-static char __init *prom_strcpy(char *dest, const char *src)
+static ssize_t __init prom_strscpy_pad(char *dest, const char *src, size_t n)
{
- char *tmp = dest;
+ ssize_t rc;
+ size_t i;
- while ((*dest++ = *src++) != '\0')
- /* nothing */;
- return tmp;
+ if (n == 0 || n > INT_MAX)
+ return -E2BIG;
+
+ // Copy up to n bytes
+ for (i = 0; i < n && src[i] != '\0'; i++)
+ dest[i] = src[i];
+
+ rc = i;
+
+ // If we copied all n then we have run out of space for the nul
+ if (rc == n) {
+ // Rewind by one character to ensure nul termination
+ i--;
+ rc = -E2BIG;
+ }
+
+ for (; i < n; i++)
+ dest[i] = '\0';
+
+ return rc;
}
static int __init prom_strncmp(const char *cs, const char *ct, size_t count)
@@ -2701,7 +2719,7 @@ static void __init flatten_device_tree(void)
/* Add "phandle" in there, we'll need it */
namep = make_room(&mem_start, &mem_end, 16, 1);
- prom_strcpy(namep, "phandle");
+ prom_strscpy_pad(namep, "phandle", sizeof("phandle"));
mem_start = (unsigned long)namep + prom_strlen(namep) + 1;
/* Build string array */
--
2.25.1
