trace: events: cleanup deprecated strncpy uses

strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

For 2 out of 3 of these changes we can simply swap in strscpy() as it
guarantess NUL-termination which is needed for the following trace
print.

trace_rpcgss_context() should use memcpy as its format specifier %.*s
allows for the length to be specifier (__entry->len). Due to this,
acceptor does not technically need to be NUL-terminated. Moreover,
swapping in strscpy() and keeping everything else the same could result
in truncation of the source string by one byte. To remedy this, we could
use `len + 1` but I am unsure of the size of the destination buffer so a
simple memcpy should suffice.
|	TP_printk("win_size=%u expiry=%lu now=%lu timeout=%u acceptor=%.*s",
|		__entry->window_size, __entry->expiry, __entry->now,
|		__entry->timeout, __entry->len, __get_str(acceptor))

I suspect acceptor not to naturally be a NUL-terminated string due to
the presence of some stringify methods.
|	.crstringify_acceptor	= gss_stringify_acceptor,

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
Link: https://github.com/KSPP/linux/issues/90
Signed-off-by: Justin Stitt <justinstitt@google.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20240401-strncpy-include-trace-events-mdio-h-v1-1-9cb5a4cda116@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/trace/events/mdio.h b/include/trace/events/mdio.h
index 0f241cbe00aba8a993f1a749fc3fad83c5062909..285b3e4f83ba53db44ed65792ddb31cd1e9aa804 100644 (file)
--- a/include/trace/events/mdio.h
+++ b/include/trace/events/mdio.h
@@ -25,7 +25,7 @@ TRACE_EVENT_CONDITION(mdio_access,
        ),
 
        TP_fast_assign(
-               strncpy(__entry->busid, bus->id, MII_BUS_ID_SIZE);
+               strscpy(__entry->busid, bus->id, MII_BUS_ID_SIZE);
                __entry->read = read;
                __entry->addr = addr;
                __entry->regnum = regnum;

diff --git a/include/trace/events/rpcgss.h b/include/trace/events/rpcgss.h
index ba2d96a1bc2f94703945c5f79294a66af1fe8fd4..274c297f1b15d516200ea36cd672b32b5f3118cf 100644 (file)
--- a/include/trace/events/rpcgss.h
+++ b/include/trace/events/rpcgss.h
@@ -618,7 +618,7 @@ TRACE_EVENT(rpcgss_context,
                __entry->timeout = timeout;
                __entry->window_size = window_size;
                __entry->len = len;
-               strncpy(__get_str(acceptor), data, len);
+               memcpy(__get_str(acceptor), data, len);
        ),
 
        TP_printk("win_size=%u expiry=%lu now=%lu timeout=%u acceptor=%.*s",

diff --git a/include/trace/events/sock.h b/include/trace/events/sock.h
index 0d1c5ce4e6a6a438fe5ee53476e5435e97e69759..3836de435d9d2763c814689cf0281c66c982011d 100644 (file)
--- a/include/trace/events/sock.h
+++ b/include/trace/events/sock.h
@@ -110,7 +110,7 @@ TRACE_EVENT(sock_exceed_buf_limit,
        ),
 
        TP_fast_assign(
-               strncpy(__entry->name, prot->name, 32);
+               strscpy(__entry->name, prot->name, 32);
                __entry->sysctl_mem[0] = READ_ONCE(prot->sysctl_mem[0]);
                __entry->sysctl_mem[1] = READ_ONCE(prot->sysctl_mem[1]);
                __entry->sysctl_mem[2] = READ_ONCE(prot->sysctl_mem[2]);