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a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1712015335; l=3378; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=4JhNkEpOiWMttmklKDS6dB8Whz9xSe93GiSKkFueDRI=; b=NKg6XG8BN99gUBI3M2EOxgxK+kUU1xCXzro+M6vtMFE/7+A6dbh9K6zgb0yyqbNaih+k6ztsO bX+IDfR2tSbBc3Hz4yHOB8t7lA0pR91YNefcOSR+Ppvq3Y+FZM5/PuR X-Mailer: b4 0.12.3 Message-ID: <20240401-strncpy-include-trace-events-mdio-h-v1-1-9cb5a4cda116@google.com> Subject: [PATCH] trace: events: cleanup deprecated strncpy uses From: Justin Stitt To: Andrew Lunn , Heiner Kallweit , Russell King , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Chuck Lever , Jeff Layton , Neil Brown , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt 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 [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt Acked-by: Chuck Lever --- Note: build-tested only. Found with: $ rg "strncpy\(" --- include/trace/events/mdio.h | 2 +- include/trace/events/rpcgss.h | 2 +- include/trace/events/sock.h | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) --- base-commit: 928a87efa42302a23bb9554be081a28058495f22 change-id: 20240401-strncpy-include-trace-events-mdio-h-0a325676b468 Best regards, -- Justin Stitt diff --git a/include/trace/events/mdio.h b/include/trace/events/mdio.h index 0f241cbe00ab..285b3e4f83ba 100644 --- 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 ba2d96a1bc2f..274c297f1b15 100644 --- 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 fd206a6ab5b8..1d0b98e6b2cc 100644 --- a/include/trace/events/sock.h +++ b/include/trace/events/sock.h @@ -109,7 +109,7 @@ 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]);