From ff736a286116d462a4067ba258fa351bc0b4ed80 Mon Sep 17 00:00:00 2001 From: Thorsten Blum Date: Wed, 26 Nov 2025 23:08:05 +0100 Subject: [PATCH] net: ipconfig: Replace strncpy with strscpy in ic_proto_name strncpy() is deprecated [1] for NUL-terminated destination buffers because it does not guarantee NUL termination. Replace it with strscpy() to ensure the destination buffer is always NUL-terminated and to avoid any additional NUL padding. Although the identifier buffer has 252 usable bytes, strncpy() copied only up to 251 bytes to the zero-initialized buffer, relying on the last byte to act as an implicit NUL terminator. Switching to strscpy() avoids this implicit behavior and does not use magic numbers. The source string is also NUL-terminated and satisfies the __must_be_cstr() requirement of strscpy(). Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Signed-off-by: Thorsten Blum Link: https://patch.msgid.link/20251126220804.102160-2-thorsten.blum@linux.dev Signed-off-by: Jakub Kicinski --- net/ipv4/ipconfig.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c index 22a7889876c1c..019408d3ca2cb 100644 --- a/net/ipv4/ipconfig.c +++ b/net/ipv4/ipconfig.c @@ -1690,7 +1690,8 @@ static int __init ic_proto_name(char *name) *v = 0; if (kstrtou8(client_id, 0, dhcp_client_identifier)) pr_debug("DHCP: Invalid client identifier type\n"); - strncpy(dhcp_client_identifier + 1, v + 1, 251); + strscpy(dhcp_client_identifier + 1, v + 1, + sizeof(dhcp_client_identifier) - 1); *v = ','; } return 1; -- 2.47.3