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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Ard Biesheuvel <ardb@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 03/29] efi: cper: fix snprintf() use in cper_dimm_err_location()
Date: Tue,  8 Jun 2021 20:26:57 +0200
Message-ID: <20210608175927.932302866@linuxfoundation.org> (raw)
In-Reply-To: <20210608175927.821075974@linuxfoundation.org>

From: Rasmus Villemoes <linux@rasmusvillemoes.dk>

[ Upstream commit 942859d969de7f6f7f2659a79237a758b42782da ]

snprintf() should be given the full buffer size, not one less. And it
guarantees nul-termination, so doing it manually afterwards is
pointless.

It's even potentially harmful (though probably not in practice because
CPER_REC_LEN is 256), due to the "return how much would have been
written had the buffer been big enough" semantics. I.e., if the bank
and/or device strings are long enough that the "DIMM location ..."
output gets truncated, writing to msg[n] is a buffer overflow.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Fixes: 3760cd20402d4 ("CPER: Adjust code flow of some functions")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/firmware/efi/cper.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index c0e54396f250..dc8d2603612e 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -257,8 +257,7 @@ static int cper_dimm_err_location(struct cper_mem_err_compact *mem, char *msg)
 	if (!msg || !(mem->validation_bits & CPER_MEM_VALID_MODULE_HANDLE))
 		return 0;
 
-	n = 0;
-	len = CPER_REC_LEN - 1;
+	len = CPER_REC_LEN;
 	dmi_memdev_name(mem->mem_dev_handle, &bank, &device);
 	if (bank && device)
 		n = snprintf(msg, len, "DIMM location: %s %s ", bank, device);
@@ -267,7 +266,6 @@ static int cper_dimm_err_location(struct cper_mem_err_compact *mem, char *msg)
 			     "DIMM location: not present. DMI handle: 0x%.4x ",
 			     mem->mem_dev_handle);
 
-	msg[n] = '\0';
 	return n;
 }
 
-- 
2.30.2




  parent reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08 18:26 [PATCH 4.9 00/29] 4.9.272-rc1 review Greg Kroah-Hartman
2021-06-08 18:26 ` [PATCH 4.9 01/29] net: usb: cdc_ncm: dont spew notifications Greg Kroah-Hartman
2021-06-08 18:26 ` [PATCH 4.9 02/29] efi: Allow EFI_MEMORY_XP and EFI_MEMORY_RO both to be cleared Greg Kroah-Hartman
2021-06-08 18:26 ` Greg Kroah-Hartman [this message]
2021-06-08 18:26 ` [PATCH 4.9 04/29] vfio/pci: Fix error return code in vfio_ecap_init() Greg Kroah-Hartman
2021-06-08 18:26 ` [PATCH 4.9 05/29] vfio/pci: zap_vma_ptes() needs MMU Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 06/29] vfio/platform: fix module_put call in error flow Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 07/29] ipvs: ignore IP_VS_SVC_F_HASHED flag when adding service Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 08/29] HID: pidff: fix error return code in hid_pidff_init() Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 09/29] HID: i2c-hid: fix format string mismatch Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 10/29] netfilter: nfnetlink_cthelper: hit EBUSY on updates if size mismatches Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 11/29] ieee802154: fix error return code in ieee802154_add_iface() Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 12/29] ieee802154: fix error return code in ieee802154_llsec_getparams() Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 13/29] Bluetooth: fix the erroneous flush_work() order Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 14/29] Bluetooth: use correct lock to prevent UAF of hdev object Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 15/29] net: caif: added cfserl_release function Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 16/29] net: caif: add proper error handling Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 17/29] net: caif: fix memory leak in caif_device_notify Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 18/29] net: caif: fix memory leak in cfusbl_device_notify Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 19/29] ALSA: timer: Fix master timer notification Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 20/29] ext4: fix bug on in ext4_es_cache_extent as ext4_split_extent_at failed Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 21/29] pid: take a reference when initializing `cad_pid` Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 22/29] ocfs2: fix data corruption by fallocate Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 23/29] nfc: fix NULL ptr dereference in llcp_sock_getname() after failed connect Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 24/29] btrfs: fix error handling in btrfs_del_csums Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 25/29] btrfs: fixup error handling in fixup_inode_link_counts Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 26/29] bnxt_en: Remove the setting of dev_port Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 27/29] KVM: SVM: Truncate GPR value for DR and CR accesses in !64-bit mode Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 28/29] arm64: Remove unimplemented syscall log message Greg Kroah-Hartman
2021-06-08 18:27 ` [PATCH 4.9 29/29] xen-pciback: redo VF placement in the virtual topology Greg Kroah-Hartman
2021-06-09  2:55 ` [PATCH 4.9 00/29] 4.9.272-rc1 review Shuah Khan
2021-06-09  9:33 ` Jon Hunter
2021-06-09 11:53 ` Naresh Kamboju
2021-06-09 18:13 ` Florian Fainelli
2021-06-09 18:47 ` Guenter Roeck

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