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=1792678145; b=47e8H6gPpti0iRWAd7qpGl+rPv6JILLuhmLFKihNzPIRVtzLbd2acBEiXP0jNtjxHzl/ UAC3ZIRD2vxPQWB/NWdSZTniG60GS1ojWEWadP0NvJuJMNo80fxYWPiK5HZxZD4etKrim OO1oWR+aT9DxPU4Xif8bD8SB3gg4PwzJXfbdqTk9G20bVwgaStyLvX819xhAKexTQgMga EhXFrLb7lNYbGZgLEz7d+MrttjKPJGMAlaXb0ccSVqxKUL5cQwwK7X1lwVOtWQrxWrvpr aDYoWwrt/k5XVcErcx06Fz3b3nKpnbOCzHhWapCCIVPhT6xvBcBU7/rwUpbXe5oFQQQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792678145; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=U7H5v4cwrTEp+TB101E5vL9gOVRXg8XCTzQ6V7Tpas4=; b=CLADpDj8C/ZGFeyYmyvJUi7lQx6Q4nnHRM7nFJaoB+07/kQmixtgWdmqkOuqF+htZxuu ZV302kz6HdhwErIutjnJAky9c8L7qAQ73aa3zxmPbhINJGkJb1KKlgRiDs7nyumwL97bu reveiIQT43XT1ZfdlgTvBCS556a6BV8Bbr/oeMHixnVJztF4RMsmLcSgqpgNyI5nMeNVq G1BMm/SvJda4J7kPzcCC0vDrI3m2/SuRMM1dz7UZ64xCOGYGqe3WyvKYh44CaR0LRnpyl Yg0MQx067hKnZC74pYQEIGnA4vWWY3+SolKxv64FPWvWy3XMI17MWYigObXBP+H4psw== 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=NVg6S7ud; 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 C4D03606A31A for ; Thu, 22 Oct 2026 14:09:04 +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=NVg6S7ud Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24F591F000C1; Thu, 22 Oct 2026 14:09:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792678144; bh=U7H5v4cwrTEp+TB101E5vL9gOVRXg8XCTzQ6V7Tpas4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=NVg6S7udMb7WtLZjr8kvIvs+YkXCQd+zZOixeSuebo61HuiMPntagS0ysAhaudMpz Y4p76ODthyDUuKru6DpoBlXueGnpVbHXczvj2RP3nQ8vIN9cXG4qGLm5DDVUscxSfE SsKk2cKs2FsQarWBuHjDQsdNu6RV9Dw4Ojfx28tCfV92BZeg5/jDUCNcusZuqMSc+m atnspau7VwgWJTiKHe2REFuOkQx+eELSyxfVhuonz2CL6/9pYdcXLDXSAX6lDp/HB0 de6YOYnuD9JPoXGOgQBSxvqWyzE0RPbtD373kfHaSqjaQK/pPxCeAnAuK5P4qxAURT /7iQzrOkZUBHA== From: Sasha Levin To: stable@vger.kernel.org Cc: Pengpeng Hou , Steven Rostedt , Sasha Levin Subject: [PATCH 6.12.y 3/4] tracing: Bound histogram expression strings with seq_buf Date: Thu, 22 Oct 2026 10:09:00 -0400 Message-ID: <20261022140848.1513845-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261022140848.1513845-1-sashal@kernel.org> References: <2026102122-sandy-lazy-aa40@gregkh> <20261022140848.1513845-1-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 5e3232c405afc..4f1c8dd3b83c3 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