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=1792673699; b=24gl18RHXM7uq6uSR8pnfs64dwTHQmddM2sUmU49NIRLjwkQXcBm5gSSy9pRpeHdxhfP taEujTMLR+8pSdQ9mXzoU3dylmsPsj+N3Tt4vllq1ao0Ej0Fjcz2f4PwBDH2A4pwOks8f QSJlCGZ6LkgKII4Fdw6wN7LPsdNp7oL1cJjkUH5Q9ThuziOx4s9sZj/GdyXTfm5uk0A9t FVU6FGCxgGY86PBbQKr1Rf+6QNYyUteJhmn7dhtGEBG2B9lypPnrQctn2IOJ6SLVbc2eP AdFDi46GtFczahXt527daFq9wH6w+V36r4lqsONNbXXJsprRes+a6H291YBtC6FWADw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792673699; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=Yyx4tf8Tr+Djx6pN0pFPyWHcoLUU9CTGfQmjCoVc0l4=; b=RBU84KH+0QycnR2FuzvVgoagkPu59gr+EA1dwKakkkeuYCUM9H13f9LZMEdqZDjmDN9k X+kp1iVKBQ1Ayg/k+fHx5kUnfw+owz//7T5czVMWR4iu73h5MXOcrA/E2DbhXmJ+uOdkt 7eyvzEsny1DV6G8qUWSo/8cTDh5OB1MlJP7JasCQ+Q2gfGLwHbgBTvuqLAiOVoNEAiTi1 fpHHWI53uqbXMuJZwPFkafQjL44fMWAGvFnYCZC+JyOAtcyLnJZAHE9rS4KvwBGvstetC 5cIPbVFx//wV0fNYD2Azr17345vfYQsr/i2AAKjBtctXnO9h59Le1HdjM5tqCYSJx+w== 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=njqxTSiy; 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 4D5AE606A319 for ; Thu, 22 Oct 2026 12:54:59 +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=njqxTSiy Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DED91F000C2; Thu, 22 Oct 2026 12:54:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792673698; bh=Yyx4tf8Tr+Djx6pN0pFPyWHcoLUU9CTGfQmjCoVc0l4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=njqxTSiyV8qgglIOiJQKBzO9s27kPUf0FAgxjB0JoF0ERSL5fNRzJ+AybrTHCdGMR r5fzITGGtpV17H43ShVU5H7soEhcGDarjPZZYFp+ZQfu7PFVn7BWtRtacWIjcFr8SN op0tecsWypAqYUlIO0IgkSLZhTNctq1eE79VrzBAXcZga4HzzfUQgQB2rCJi0Ehj9A ocWUrcKXRWtFV5XsXyBJ9UADhlJofA0AtSsX7nWGltXp6aeNDlRjkoKHKqdISfDrqp NcVgBdTjiEueo+r0wfnlb8Wofbs3YGmAsO/YqwuExHNFiORM/+gX7Gx1rtKlNXwYOC j8sdhpTMbKbNA== From: Sasha Levin To: stable@vger.kernel.org Cc: Pengpeng Hou , Steven Rostedt , Sasha Levin Subject: [PATCH 7.2.y 2/3] tracing: Bound histogram expression strings with seq_buf Date: Thu, 22 Oct 2026 08:54:55 -0400 Message-ID: <20261022125436.1346436-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261022125436.1346436-1-sashal@kernel.org> References: <2026102121-bronchial-ozone-0317@gregkh> <20261022125436.1346436-1-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 81bb1cf96c751..8caeb6bfb7d5e 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 { @@ -1732,33 +1731,36 @@ 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; @@ -1767,47 +1769,54 @@ 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