From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 79B2D478E50; Tue, 16 Jun 2026 17:16:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781630164; cv=none; b=sdKEbIqaAnuLw/QArAbi2xmxsKLjQQkZbKS2if/cZx4BgVDD+BIW/loJm6xg1YVUjmJotPFciLhhMFf3XhoxrV43oqdloSNiXWwDqM6XxPs2iMkfE3eFOLzWK8KKLHHK3H9+QFFpKhYTKl+q95pvfyqqtHvCWBHxUza0pquoT/A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781630164; c=relaxed/simple; bh=95DudTWTjV7RVGR8OaEmKR8EqxHvVN1qsM8DxatFgHc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PSIzFKieoAs+PnMJSF5a50iQ+7lpG4dmvn9IfgaEqsN2c7/JZEKd5IEgdIvGTrd9QrEfTI0mp5rvCBEHrJbYo4Fc5ZWFXXsnsBo+mt4XkcUtFWP4XbYcndrvyHLqgsxeP7iD+CYgk44U3LX0B+3ZMXhcaohOj/zQP6tRnBaUM2s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=S/Ul5VxH; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="S/Ul5VxH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E15571F000E9; Tue, 16 Jun 2026 17:16:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781630161; bh=AlLRMO/RyRJ4yYCORYroaXR3yXi6VmD0BFrRxQwM2zE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=S/Ul5VxHzwjKLhcT9JYOZ599qUlR92T8iaJ7KTzE/H8z65gFWUDRR+Re1I3LlYx4M lekX6nKftnUqoCpGfJJ3qgIHqOvvXUMpkX6SN5DnukJF95ocNQ3+Fsos5wi278O0Jw Ws5Vjjrr0jyWRqexkqX1OFz/zdfQdB2EdjQcwSEM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michael Bommarito , Mika Westerberg , Sasha Levin Subject: [PATCH 6.6 423/452] thunderbolt: property: Cap recursion depth in __tb_property_parse_dir() Date: Tue, 16 Jun 2026 20:30:50 +0530 Message-ID: <20260616145138.944965963@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145117.796205997@linuxfoundation.org> References: <20260616145117.796205997@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Bommarito [ Upstream commit 928abe19fbf0127003abcb1ea69cabc1c897d0ab ] A DIRECTORY entry's value field is used as the dir_offset for a recursive call into __tb_property_parse_dir() with no depth counter. A crafted peer that chains DIRECTORY entries into a back-reference loop drives the parser until the kernel stack is exhausted and the guard page fires. Any untrusted XDomain peer (cable, dock, in-line inspector, adjacent host) that reaches the PROPERTIES_REQUEST control-plane exchange can trigger this without authentication. Thread a depth counter through tb_property_parse() and __tb_property_parse_dir(), and reject blocks that exceed TB_PROPERTY_MAX_DEPTH = 8. That is comfortably larger than any observed legitimate XDomain layout. Operators who do not need XDomain host-to-host discovery can disable the path entirely with thunderbolt.xdomain=0 on the kernel command line. Fixes: cdae7c07e3e3 ("thunderbolt: Add support for XDomain properties") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Assisted-by: Codex:gpt-5-4 Signed-off-by: Michael Bommarito Signed-off-by: Mika Westerberg Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/thunderbolt/property.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) --- a/drivers/thunderbolt/property.c +++ b/drivers/thunderbolt/property.c @@ -35,10 +35,11 @@ struct tb_property_dir_entry { }; #define TB_PROPERTY_ROOTDIR_MAGIC 0x55584401 +#define TB_PROPERTY_MAX_DEPTH 8 static struct tb_property_dir *__tb_property_parse_dir(const u32 *block, size_t block_len, unsigned int dir_offset, size_t dir_len, - bool is_root); + bool is_root, unsigned int depth); static inline void parse_dwdata(void *dst, const void *src, size_t dwords) { @@ -99,7 +100,8 @@ tb_property_alloc(const char *key, enum } static struct tb_property *tb_property_parse(const u32 *block, size_t block_len, - const struct tb_property_entry *entry) + const struct tb_property_entry *entry, + unsigned int depth) { char key[TB_PROPERTY_KEY_SIZE + 1]; struct tb_property *property; @@ -120,7 +122,7 @@ static struct tb_property *tb_property_p switch (property->type) { case TB_PROPERTY_TYPE_DIRECTORY: dir = __tb_property_parse_dir(block, block_len, entry->value, - entry->length, false); + entry->length, false, depth + 1); if (!dir) { kfree(property); return NULL; @@ -165,13 +167,17 @@ static struct tb_property *tb_property_p } static struct tb_property_dir *__tb_property_parse_dir(const u32 *block, - size_t block_len, unsigned int dir_offset, size_t dir_len, bool is_root) + size_t block_len, unsigned int dir_offset, size_t dir_len, bool is_root, + unsigned int depth) { const struct tb_property_entry *entries; size_t i, content_len, nentries; unsigned int content_offset; struct tb_property_dir *dir; + if (depth > TB_PROPERTY_MAX_DEPTH) + return NULL; + dir = kzalloc(sizeof(*dir), GFP_KERNEL); if (!dir) return NULL; @@ -206,7 +212,7 @@ static struct tb_property_dir *__tb_prop for (i = 0; i < nentries; i++) { struct tb_property *property; - property = tb_property_parse(block, block_len, &entries[i]); + property = tb_property_parse(block, block_len, &entries[i], depth); if (!property) { tb_property_free_dir(dir); return NULL; @@ -243,7 +249,7 @@ struct tb_property_dir *tb_property_pars return NULL; return __tb_property_parse_dir(block, block_len, 0, rootdir->length, - true); + true, 0); } /**