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net: ipconfig: Replace strncpy with strscpy in ic_proto_name

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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 <thorsten.blum@linux.dev>
Link: https://patch.msgid.link/20251126220804.102160-2-thorsten.blum@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Thorsten Blum
2025-11-26 23:08:05 +01:00
committed by Jakub Kicinski
parent 840a64710e
commit ff736a2861
1 changed files with 2 additions and 1 deletions
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3
net/ipv4/ipconfig.c
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@@ -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;