From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F085F3B7B98; Sat, 12 Sep 2026 20:05:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789243558; cv=none; b=gcRQZHBRcivqr2Ov5oiBAFjD+sXoXSZP7BHiw5PI+fGSlPBm+/ScgwPr0W321Bp2TEF6g1xwyGPWMGf65eIovWiLcuOpZ7t/9KrSQzXlEahhG490mVgv4802HCkzgD41rRSWrhzv3xLWVRt2XYzEca7oHRNznP8UON1Aawf1ttw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789243558; c=relaxed/simple; bh=6df8S8873ui2OlDKQXuxnnMlsY5C0spRrym3facaNQ4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=W2dmdj9mqMhiSCzvTmnpyGS4X+G2Lr6fS6jX4uKn85bNUcuLF3QxkVg1DiiKG63wMJFm1ifxsgkk1v9xvsmFuJPUrps3bgvJ0qZLfQ1pfCTjmKCngbOowuFUgWQVWF3MXhG1f+NUSghzy0oVgaAcxK6b9J4yPPV/7DCK8or1BAQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vlaslRhB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="vlaslRhB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 931301F00893; Sat, 12 Sep 2026 20:05:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789243555; bh=cR496ZSpNMJVRd5ZNt7dGLw2f93O+cNloNw3HcLfNQk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=vlaslRhBCYMP1wolH3c300DBJGj6i9RduKjQnfrKHvzNZN+RYdU2C3CEP5jEixhKI g++wAO6WCoew+N2PefZFi8lhsu7sSvjRFMtE/HPPFLzqF5XPi1o7p4zmRiTOFukqhs Fx7ICTh8IjRAAb6EyBnz8BFGfBMzQtGyTCo7NJXg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chuck Lever III , "Steven Rostedt (VMware)" , Sasha Levin Subject: [PATCH 5.10 797/798] tracing: Handle %.*s in trace_check_vprintf() Date: Sat, 12 Sep 2026 09:07:05 +0200 Message-ID: <20260912065535.328163177@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065516.948645775@linuxfoundation.org> References: <20260912065516.948645775@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt (VMware) [ Upstream commit eb01f5353bdaa59600b29d864819056a0e3de24d ] If a trace event uses the %*.s notation, the trace_check_vprintf() will fail and will warn about a bad processing of strings, because it does not take into account the length field when processing the star (*) part. Have it handle this case as well. Link: https://lore.kernel.org/linux-nfs/238C0E2D-C2A4-4578-ADD2-C565B3B99842@oracle.com/ Reported-by: Chuck Lever III Fixes: 9a6944fee68e2 ("tracing: Add a verifier to check string pointers for trace events") Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Sasha Levin --- kernel/trace/trace.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bfa6e2fe984b1..6c8f9a401fe0b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3708,6 +3708,9 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt, goto print; while (*p) { + bool star = false; + int len = 0; + j = 0; /* We only care about %s and variants */ @@ -3729,13 +3732,17 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt, /* Need to test cases like %08.*s */ for (j = 1; p[i+j]; j++) { if (isdigit(p[i+j]) || - p[i+j] == '*' || p[i+j] == '.') continue; + if (p[i+j] == '*') { + star = true; + continue; + } break; } if (p[i+j] == 's') break; + star = false; } j = 0; } @@ -3748,6 +3755,9 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt, iter->fmt[i] = '\0'; trace_seq_vprintf(&iter->seq, iter->fmt, ap); + if (star) + len = va_arg(ap, int); + /* The ap now points to the string data of the %s */ str = va_arg(ap, const char *); @@ -3766,8 +3776,18 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt, int ret; /* Try to safely read the string */ - ret = strncpy_from_kernel_nofault(iter->fmt, str, - iter->fmt_size); + if (star) { + if (len + 1 > iter->fmt_size) + len = iter->fmt_size - 1; + if (len < 0) + len = 0; + ret = copy_from_kernel_nofault(iter->fmt, str, len); + iter->fmt[len] = 0; + star = false; + } else { + ret = strncpy_from_kernel_nofault(iter->fmt, str, + iter->fmt_size); + } if (ret < 0) trace_seq_printf(&iter->seq, "(0x%px)", str); else @@ -3779,7 +3799,10 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt, strncpy(iter->fmt, p + i, j + 1); iter->fmt[j+1] = '\0'; } - trace_seq_printf(&iter->seq, iter->fmt, str); + if (star) + trace_seq_printf(&iter->seq, iter->fmt, len, str); + else + trace_seq_printf(&iter->seq, iter->fmt, str); p += i + j + 1; } -- 2.53.0