[PATCH 5.15 66/69] EDAC/ghes: Set the DIMM label unconditionally

Greg Kroah-Hartman
2022-08-01T12:07:29Z

From: Toshi Kani <toshi.kani@hpe.com>

commit 5e2805d5379619c4a2e3ae4994e73b36439f4bad upstream.

The commit

cb51a371d08e ("EDAC/ghes: Setup DIMM label from DMI and use it in error reports")

enforced that both the bank and device strings passed to
dimm_setup_label() are not NULL.

However, there are BIOSes, for example on a

HPE ProLiant DL360 Gen10/ProLiant DL360 Gen10, BIOS U32 03/15/2019

which don't populate both strings:

Handle 0x0020, DMI type 17, 84 bytes
Memory Device
Array Handle: 0x0013
Error Information Handle: Not Provided
Total Width: 72 bits
Data Width: 64 bits
Size: 32 GB
Form Factor: DIMM
Set: None
Locator: PROC 1 DIMM 1 <===== device
Bank Locator: Not Specified <===== bank

This results in a buffer overflow because ghes_edac_register() calls
strlen() on an uninitialized label, which had non-zero values left over
from krealloc_array():

detected buffer overflow in __fortify_strlen
------------[ cut here ]------------
kernel BUG at lib/string_helpers.c:983!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G I 5.18.6-200.fc36.x86_64 #1
Hardware name: HPE ProLiant DL360 Gen10/ProLiant DL360 Gen10, BIOS U32 03/15/2019
RIP: 0010:fortify_panic
...
Call Trace:
<TASK>
ghes_edac_register.cold
ghes_probe
platform_probe
really_probe
__driver_probe_device
driver_probe_device
__driver_attach
? __device_attach_driver
bus_for_each_dev
bus_add_driver
driver_register
acpi_ghes_init
acpi_init
? acpi_sleep_proc_init
do_one_initcall

The label contains garbage because the commit in Fixes reallocs the
DIMMs array while scanning the system but doesn't clear the newly
allocated memory.

Change dimm_setup_label() to always initialize the label to fix the
issue. Set it to the empty string in case BIOS does not provide both
bank and device so that ghes_edac_register() can keep the default label
given by edac_mc_alloc_dimms().

[ bp: Rewrite commit message. ]

Fixes: b9cae27728d1f ("EDAC/ghes: Scan the system once on driver init")
Co-developed-by: Robert Richter <rric@kernel.org>
Signed-off-by: Robert Richter <rric@kernel.org>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Robert Elliott <elliott@hpe.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220719220124.760359-1-toshi.kani@hpe.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/edac/ghes_edac.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -101,9 +101,14 @@ static void dimm_setup_label(struct dimm

dmi_memdev_name(handle, &bank, &device);

- /* both strings must be non-zero */
- if (bank && *bank && device && *device)
- snprintf(dimm->label, sizeof(dimm->label), "%s %s", bank, device);
+ /*
+ * Set to a NULL string when both bank and device are zero. In this case,
+ * the label assigned by default will be preserved.
+ */
+ snprintf(dimm->label, sizeof(dimm->label), "%s%s%s",
+ (bank && *bank) ? bank : "",
+ (bank && *bank && device && *device) ? " " : "",
+ (device && *device) ? device : "");
}

static void assign_dmi_dimm_info(struct dimm_info *dimm, struct memdev_dmi_entry *entry)