FAILED: patch "[PATCH] iommu/amd: Add a length limitation for the ivrs_acpihid" failed to apply to 4.14-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.14.y
git checkout FETCH_HEAD
git cherry-pick -x b6b26d86c61c441144c72f842f7469bb686e1211
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '1678182911197225@xxxxxxxxx' --subject-prefix 'PATCH 4.14.y' HEAD^..

Possible dependencies:

b6b26d86c61c ("iommu/amd: Add a length limitation for the ivrs_acpihid command-line parameter")
1198d2316dc4 ("iommu/amd: Fix ill-formed ivrs_ioapic, ivrs_hpet and ivrs_acpihid options")
bbe3a106580c ("iommu/amd: Add PCI segment support for ivrs_[ioapic/hpet/acpihid] commands")
42bb5aa04338 ("iommu/amd: Increase timeout waiting for GA log enablement")
03ebe48e235f ("Merge branches 'iommu/fixes', 'arm/renesas', 'arm/mediatek', 'arm/tegra', 'arm/omap', 'arm/smmu', 'x86/vt-d', 'x86/amd' and 'core' into next")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From b6b26d86c61c441144c72f842f7469bb686e1211 Mon Sep 17 00:00:00 2001
From: Gavrilov Ilia <Ilia.Gavrilov@xxxxxxxxxxx>
Date: Thu, 2 Feb 2023 08:26:56 +0000
Subject: [PATCH] iommu/amd: Add a length limitation for the ivrs_acpihid
 command-line parameter

The 'acpiid' buffer in the parse_ivrs_acpihid function may overflow,
because the string specifier in the format string sscanf()
has no width limitation.

Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with SVACE.

Fixes: ca3bf5d47cec ("iommu/amd: Introduces ivrs_acpihid kernel parameter")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ilia.Gavrilov <Ilia.Gavrilov@xxxxxxxxxxx>
Reviewed-by: Kim Phillips <kim.phillips@xxxxxxx>
Link: https://lore.kernel.org/r/20230202082719.1513849-1-Ilia.Gavrilov@xxxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 467b194975b3..19a46b9f7357 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3475,15 +3475,26 @@ static int __init parse_ivrs_hpet(char *str)
 	return 1;
 }
 
+#define ACPIID_LEN (ACPIHID_UID_LEN + ACPIHID_HID_LEN)
+
 static int __init parse_ivrs_acpihid(char *str)
 {
 	u32 seg = 0, bus, dev, fn;
 	char *hid, *uid, *p, *addr;
-	char acpiid[ACPIHID_UID_LEN + ACPIHID_HID_LEN] = {0};
+	char acpiid[ACPIID_LEN] = {0};
 	int i;
 
 	addr = strchr(str, '@');
 	if (!addr) {
+		addr = strchr(str, '=');
+		if (!addr)
+			goto not_found;
+
+		++addr;
+
+		if (strlen(addr) > ACPIID_LEN)
+			goto not_found;
+
 		if (sscanf(str, "[%x:%x.%x]=%s", &bus, &dev, &fn, acpiid) == 4 ||
 		    sscanf(str, "[%x:%x:%x.%x]=%s", &seg, &bus, &dev, &fn, acpiid) == 5) {
 			pr_warn("ivrs_acpihid%s option format deprecated; use ivrs_acpihid=%s@%04x:%02x:%02x.%d instead\n",
@@ -3496,6 +3507,9 @@ static int __init parse_ivrs_acpihid(char *str)
 	/* We have the '@', make it the terminator to get just the acpiid */
 	*addr++ = 0;
 
+	if (strlen(str) > ACPIID_LEN + 1)
+		goto not_found;
+
 	if (sscanf(str, "=%s", acpiid) != 1)
 		goto not_found;