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=1792775016; b=LpgKm89EvaqaDOTP7aevHpRv97QCYNMi+zNB1Dney3WHKxUr9uLZimesU5e8iHEpxLY8 xLgQUXNMEppDuvkOY52x+MbcS+iRqgRBdCPbGKo3+GgmRFZlStgnJUUutjh1omiiXJqdg mogbj0ZMawlpn0ARgzY4TFcexgeSQa9afAWIcauDRHXvrw4YQIYmzJlWsgjXgnun/UxLT uqxB7LaVTYfUubriTfc4StxllGXeAiNOSqGjhJc6e0RXbnSV/vvRq90tA/jjrpibMkn24 METOndBHxaljn+e2QfzJL4Zni/rxFo8BJn7DRKMAWsoiV6/TGZuKOxEzRmXwWUDJvFw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792775016; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=lkCWrfBsGNXHGvxInNpqE400j3EvOdwvz36VK1rYuIc=; b=sVccYE8uJI996DXyQ2r+uVpz2DumVPNvpN3Nfc6uJNp+TeMpK0H7tkumYMFTQrXDjSOu Vki+Nieale/cvmclM7Bl4UaVvsud0Onadb1ApOE/PT1x3qDAyVGrFoR0RaABN/EJADgX/ bHcibk3U5k98ytr+nRV7+u/6x1Rakwr+wKWBPrzxL5LJ0xNlOo6129i66M5sgbnmkKnrE VnmEQg7JGzuL67+Zv8idLGy2qhIqMUdnVR4outhngvpIxICpuSCymQs9oKu/gQYFfEFBg pAjjRqDT16rqlETJXbygU297g9ZqBnHycpNKMenJpMW+vg9tJ2hZC59eX5YDHzErsKg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=aQHkak16; 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 641A6606A31A; Fri, 23 Oct 2026 17:03:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=aQHkak16 Received: by smtp.kernel.org (Postfix) with ESMTPSA id B10681F01825; Fri, 23 Oct 2026 17:03:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792775016; bh=lkCWrfBsGNXHGvxInNpqE400j3EvOdwvz36VK1rYuIc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=aQHkak16KJR8wrIFrO9DLMTuYbS3gBbJjs+jCCSUZy+gpRE19jKqU6FEiIOeGzije tuRPav7IfFQRLuJUo/KeijJA6Wxgd4lrPgZlyKMzLE8oBKAekvB7Uy6SItVdlj6hQo Xks0CwtioMu79g5iviAhZs/KFJi+0/+s3q4v4Wz8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pengpeng Hou , Steven Rostedt , Sasha Levin Subject: [PATCH 7.2 233/242] tracing: Bound histogram expression strings with seq_buf Date: Fri, 23 Oct 2026 18:41:15 +0200 Message-ID: <20261023163719.360120941@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163713.816071858@linuxfoundation.org> References: <20261023163713.816071858@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_hist.c | 57 ++++++++++++++++++++++----------------- 1 file changed, 33 insertions(+), 24 deletions(-) --- 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 h #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( 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 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); }