From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792678671; b=qFM3FpUJRzPtd2cq83EAeFaNTIcuhsoTe0FjmXu/b6FP4JJswK7tPcQ6uxC2TgSGLtG/ Sn76U+j/bD9MtUM1sL6UUn26jOP3IYAKVJgYjcVS1Yq1wcqovZbDPH8E+PVTjpbbX1YLm ZNGOqfERjj4WbXQjQ/3nacruAqwhoRXL/vgyJZqYfc27bmKGs4d2XoXxv1ao0v0fnsLiX H5bwa5e7aCySfCaxksLV283KJngfsuvoGP0NCX+2JESeLVYJAJWNLAK+WwFadee6b2FuQ g2L4O+NPEdN0GExtpnibeYtiEdfy5c8h6kRYNsYmrf0nTJT/ZKJiL1hmqDyFsFLRqqA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792678671; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=QA9P42Wdu8JUDlHjBd91kvi4yL9Bh5YijuXTQwH8Hws=; b=mlXScb8gP9A7VVgddKOEcffzNBlXOTNdiZV2vJnPmoANHXtw92gzSGBMC026sDaSSHD4 Jjm4xOWKfgmQDge4nRH+ANswZpe8kCaP++32EyVyvp1lKDlMqXYXjc2ZLbvDjPcwsSvbi acu8+o5pPtUssRJQei2MnfHFRwjO+p9NiYkrI+L1bTSeDHJ1pGJIZkMku/wOe+bNwaHSa D31/r4U3YsJLnIA8RT855tQSRtxeCY+blj2zSX9A73VmKOrysqotv8drssU5+fBBulMfq hutDKUCY6bqTWW5ChBLblDKfnEerOg1RwJmGyXl9F8cRLfLXah8zssxVgoFm4qGUMhA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=fMDlh+gH; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9704B606A321 for ; Thu, 22 Oct 2026 14:17:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=fMDlh+gH Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB49A1F000C4; Thu, 22 Oct 2026 14:17:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792678671; bh=QA9P42Wdu8JUDlHjBd91kvi4yL9Bh5YijuXTQwH8Hws=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fMDlh+gHywroDxG8wpPe5Y4dkTNr1/WVeqUuRWc3KcvvOqKYHWMfVYECjHPmN7fHL /0L5uL/PmS6awOI13aO/6EiszvtFHg/33TCG8kNUd7M59bsnbvDg/67I4mjINR0n2d uMMxF1vY+fNiGBlPaPF17rlPEdwku/DLRrIY1n9tVUyXqLxIhSe82Qt08r+imq1FAz sqGAfS1h/JEc242CYhEyFhtSpR91geHxZXJZv0UK+tZkM0qXFoWSGLDPZMJCX9GQqP ZPE4zAr/OzkO+89gSdTaSHp7IM0ZUg/Lia8Su8EUgDW7N20v3fOwwVmIPvVUNaRTM7 1YADYGGyDYwzQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Pengpeng Hou , Steven Rostedt , Sasha Levin Subject: [PATCH 6.6.y 3/4] tracing: Bound histogram expression strings with seq_buf Date: Thu, 22 Oct 2026 10:17:47 -0400 Message-ID: <20261022141718.1585988-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261022141718.1585988-1-sashal@kernel.org> References: <2026102123-crushable-fragrance-1b92@gregkh> <20261022141718.1585988-1-sashal@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Pengpeng Hou [ Upstream commit 935601a4276f28105498609f7f98aa66e86e9c96 ] expr_str() allocates a fixed MAX_FILTER_STR_VAL buffer and then builds expression names with a series of raw strcat() appends. Nested operands, constants, field flags, and generated field names can push the rendered string past that fixed limit before the name is attached to the hist field. Build expression strings with seq_buf and return -E2BIG when the rendered name would exceed MAX_FILTER_STR_VAL. This keeps the existing tracing-side limit while replacing the raw append logic with bounded construction. Link: https://patch.msgid.link/20260611055945.22348-4-pengpeng@iscas.ac.cn Signed-off-by: Pengpeng Hou Signed-off-by: Steven Rostedt Stable-dep-of: a0777b9e5315 ("tracing: Fix NULL dereference when copying keys for a field variable") Signed-off-by: Sasha Levin --- kernel/trace/trace_events_hist.c | 57 ++++++++++++++++++-------------- 1 file changed, 33 insertions(+), 24 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 68939bb7fdbc0..a3b0a8fa428a8 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -94,7 +94,6 @@ typedef u64 (*hist_field_fn_t) (struct hist_field *field, #define HIST_FIELD_OPERANDS_MAX 2 #define HIST_FIELDS_MAX (TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX) #define HIST_ACTIONS_MAX 8 -#define HIST_CONST_DIGITS_MAX 21 #define HIST_DIV_SHIFT 20 /* For optimizing division by constants */ enum field_op_id { @@ -1725,33 +1724,36 @@ static const char *get_hist_field_flags(struct hist_field *hist_field) return flags_str; } -static void expr_field_str(struct hist_field *field, char *expr) +static bool expr_field_str(struct hist_field *field, struct seq_buf *s) { + const char *field_name; + if (field->flags & HIST_FIELD_FL_VAR_REF) { if (!field->system) - strcat(expr, "$"); - } else if (field->flags & HIST_FIELD_FL_CONST) { - char str[HIST_CONST_DIGITS_MAX]; + seq_buf_putc(s, '$'); + } else if (field->flags & HIST_FIELD_FL_CONST) + seq_buf_printf(s, "%llu", field->constant); - snprintf(str, HIST_CONST_DIGITS_MAX, "%llu", field->constant); - strcat(expr, str); - } + field_name = hist_field_name(field, 0); + if (!field_name) + return false; - strcat(expr, hist_field_name(field, 0)); + seq_buf_puts(s, field_name); if (field->flags && !(field->flags & HIST_FIELD_FL_VAR_REF)) { const char *flags_str = get_hist_field_flags(field); - if (flags_str) { - strcat(expr, "."); - strcat(expr, flags_str); - } + if (flags_str) + seq_buf_printf(s, ".%s", flags_str); } + + return !seq_buf_has_overflowed(s); } static char *expr_str(struct hist_field *field, unsigned int level) { char *expr __free(kfree) = NULL; + struct seq_buf s; if (level > 1) return NULL; @@ -1760,47 +1762,54 @@ static char *expr_str(struct hist_field *field, unsigned int level) if (!expr) return NULL; + seq_buf_init(&s, expr, MAX_FILTER_STR_VAL); + if (!field->operands[0]) { - expr_field_str(field, expr); + if (!expr_field_str(field, &s)) + return ERR_PTR(-E2BIG); + return_ptr(expr); } if (field->operator == FIELD_OP_UNARY_MINUS) { char *subexpr; - strcat(expr, "-("); subexpr = expr_str(field->operands[0], ++level); if (!subexpr) return NULL; - strcat(expr, subexpr); - strcat(expr, ")"); - + seq_buf_printf(&s, "-(%s)", subexpr); kfree(subexpr); + if (seq_buf_has_overflowed(&s)) + return ERR_PTR(-E2BIG); + return_ptr(expr); } - expr_field_str(field->operands[0], expr); + if (!expr_field_str(field->operands[0], &s)) + return ERR_PTR(-E2BIG); switch (field->operator) { case FIELD_OP_MINUS: - strcat(expr, "-"); + seq_buf_putc(&s, '-'); break; case FIELD_OP_PLUS: - strcat(expr, "+"); + seq_buf_putc(&s, '+'); break; case FIELD_OP_DIV: - strcat(expr, "/"); + seq_buf_putc(&s, '/'); break; case FIELD_OP_MULT: - strcat(expr, "*"); + seq_buf_putc(&s, '*'); break; default: return NULL; } - expr_field_str(field->operands[1], expr); + if (seq_buf_has_overflowed(&s) || + !expr_field_str(field->operands[1], &s)) + return ERR_PTR(-E2BIG); return_ptr(expr); } -- 2.53.0