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=1792680821; b=MumbebUZSW5IQmMz/ui4NmD0HgQqgGoIWLNACJfD9z3tQX8wQ/bb28m31AuVaSyWqfz2 Fs87/B48F94cEKixx86XfOy3Ahe8hvFxGGs3iGW02Vkk+97YuODX1ZFPkrJiuoaJ/MM0w nBdPQKfnj7jYSoRs7z152Z2+Eke6oPl+8RO0jPoioJhe7l+qD6Ho1Iez336Rhh0TvAaGx tg57QBojJAKIVerEgex4HxAllv2nHv/DpDWEySw5drthA5punLKpYw1kk4mSGLvMzsXpQ +yNaDY0nsVVBb3FSTy1R9vHlyBS0QGgiSDpwH+PjIDYs0kl8NgMEAvMCc77nXs1SwTw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792680821; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=IeNvWa19c8pPq/Jp8DeSeaRIQHNdutrDA07L8wNK3vk=; b=o52I+WTIsykEu+Us0Bagg1eIyprx2IOw4q0rlpMey6nFAj+epLQMeC8FVetDWsI79HjM w3GeW+QdMcVeNLg9uNXwq+Qcv5+vQEY4UpQq8oPvr238ey22bBtul3hscVP6zsSfJ3I6B bx4zu8d2/A44eNRXdy2R7RgV2cLiHgZZoXRlRnlJMVJB4s+ZNGUvfkVV0CtGjlOqU1Lkm KDZXSiBD/4L6IE/LG+TWzh2rGFqRbhHuHpJTwJBkjkJpFUfsePOOmSOyuWZZKLC8HvEix JuKDFWrZ/FYcGGh+f5IL11SwyFqeQBVhaz8AWQMDXJQm4Ok3xEyL6A9y9OStdhEifmA== 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=AolWh892; 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 CF75A606A323 for ; Thu, 22 Oct 2026 14:53:40 +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=AolWh892 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F17F1F000C5; Thu, 22 Oct 2026 14:53:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792680820; bh=IeNvWa19c8pPq/Jp8DeSeaRIQHNdutrDA07L8wNK3vk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=AolWh89279iW3Lyb6nrYGVV+b2vxRiX1ekuHIqlch9oqOirLmEXu9JCsHirCA3P9H vKtrb5pUgYeB9cTkE6HD7ao9LeLCyulouWE+imhYf5dP0hvSs/MgJNncRxNEnnlLdO 4QDockGWc1X1uu9EABztEsJ1gPlyyVia4/XbQULzjP3zSolDCe44+aHyUujKDkabWO fFJm4T+BmenlSMquLp0YRBQNsS3Ec7cp+Y1ZyuDo+N3KkPHDCVIc0Zv/xfCGUHAIDX 68uBOq2/HrlL9VRiDfTPRA3ZfE4/Ah6l2a8QfviXV9eg9rAr6v298hXEwZlcawN9xd Oh6YO2AOYOgIQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Pengpeng Hou , Steven Rostedt , Sasha Levin Subject: [PATCH 6.1.y 3/4] tracing: Bound histogram expression strings with seq_buf Date: Thu, 22 Oct 2026 10:53:36 -0400 Message-ID: <20261022145315.1599452-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261022145315.1599452-1-sashal@kernel.org> References: <2026102123-faceplate-shallow-02a0@gregkh> <20261022145315.1599452-1-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 96dd7cbe116fa..18e3503bdc79b 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -93,7 +93,6 @@ 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 { @@ -1710,33 +1709,36 @@ 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; @@ -1745,47 +1747,54 @@ 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