On Fri, Oct 07, 2022 at 08:56:18AM +0200, Sascha Hauer wrote:
> When pci_create_attr() fails then pci_remove_resource_files() is called
> which will iterate over the res_attr[_wc] arrays and frees every non
> NULL entry. To avoid a double free here we have to set the failed entry
> to NULL in pci_create_attr() when freeing it.
>
You might consider applying this alternative version instead which IMO
looks a bit better.
Sascha
-------------------------------8<-----------------------------
>From fe8e0e6f914c14395c751b7dc165967b12427995 Mon Sep 17 00:00:00 2001
From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Date: Fri, 7 Oct 2022 07:35:35 +0200
Subject: [PATCH] PCI/sysfs: Fix double free in error path
When pci_create_attr() fails then pci_remove_resource_files() is called
which will iterate over the res_attr[_wc] arrays and frees every non
NULL entry. To avoid a double free here set the array entry only after
it's clear we successfully initialized it.
Fixes: b562ec8f74e4 ("PCI: Don't leak memory if sysfs_create_bin_file() fails")
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
drivers/pci/pci-sysfs.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index fc804e08e3cb5..6dd4050c9f2ed 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1174,11 +1174,9 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine)
sysfs_bin_attr_init(res_attr);
if (write_combine) {
- pdev->res_attr_wc[num] = res_attr;
sprintf(res_attr_name, "resource%d_wc", num);
res_attr->mmap = pci_mmap_resource_wc;
} else {
- pdev->res_attr[num] = res_attr;
sprintf(res_attr_name, "resource%d", num);
if (pci_resource_flags(pdev, num) & IORESOURCE_IO) {
res_attr->read = pci_read_resource_io;
@@ -1196,10 +1194,17 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine)
res_attr->size = pci_resource_len(pdev, num);
res_attr->private = (void *)(unsigned long)num;
retval = sysfs_create_bin_file(&pdev->dev.kobj, res_attr);
- if (retval)
+ if (retval) {
kfree(res_attr);
+ return retval;
+ }
+
+ if (write_combine)
+ pdev->res_attr_wc[num] = res_attr;
+ else
+ pdev->res_attr[num] = res_attr;
- return retval;
+ return 0;
}
/**
--
2.30.2
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
