From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Pengpeng Hou <pengpeng@iscas.ac.cn>,
	Ankit Soni <Ankit.Soni@amd.com>,
	Will Deacon <will@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 079/389] iommu/amd: Bound the early ACPI HID map
Date: Mon, 17 Aug 2026 15:28:38 +0200
Message-ID: <20260817132542.180923599@linuxfoundation.org>
In-Reply-To: <20260817132538.796021292@linuxfoundation.org>
References: <20260817132538.796021292@linuxfoundation.org>
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5.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Pengpeng Hou <pengpeng@iscas.ac.cn>

[ Upstream commit fb80117fddb5b477218dc99bb53911b72c3847f8 ]

The ivrs_acpihid command-line parser appends entries to a fixed
four-element early_acpihid_map array. Unlike the sibling IOAPIC and HPET
parsers, it does not reject a fifth entry before incrementing the map size.

Check the capacity at the common found label before parsing the HID and
UID or writing the entry.

Fixes: ca3bf5d47cec ("iommu/amd: Introduces ivrs_acpihid kernel parameter")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Ankit Soni <Ankit.Soni@amd.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iommu/amd/init.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 1ba6adb5b91241..1b7a0fae423ce9 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3227,6 +3227,12 @@ static int __init parse_ivrs_acpihid(char *str)
 	return 1;
 
 found:
+	if (early_acpihid_map_size == EARLY_MAP_SIZE) {
+		pr_err("Early ACPI HID map overflow - ignoring ivrs_acpihid%s\n",
+		       str);
+		return 1;
+	}
+
 	p = acpiid;
 	hid = strsep(&p, ":");
 	uid = p;
-- 
2.53.0