Sysfs includes entries to memory that backs a PCI device's BARs, both I/O
Port space and MMIO. This memory regions correspond to the device's
internal status and control registers used to drive the device.
Accessing these registers from userspace such as "udevadm info
--attribute-walk --path=/sys/devices/..." does can not be allowed as
such accesses outside of the driver, even just reading, can yield
catastrophic consequences.
Udevadm-info skips parsing a specific set of sysfs entries including
'resource'. This patch extends the set to include the additional
'resource<N>' entries that correspond to a PCI device's BARs.
Reported-by: Xiangliang Yu <yuxiangl@xxxxxxxxxxx>
Signed-off-by: Myron Stowe <myron.stowe@xxxxxxxxxx>
---
src/udevadm-info.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/src/udevadm-info.c b/src/udevadm-info.c
index ee9b59f..298acb5 100644
--- a/src/udevadm-info.c
+++ b/src/udevadm-info.c
@@ -37,13 +37,18 @@ static bool skip_attribute(const char *name)
"uevent",
"dev",
"modalias",
- "resource",
"driver",
"subsystem",
"module",
};
unsigned int i;
+ /*
+ * Skip any sysfs 'resource' entries, including 'resource<N>' entries
+ * that correspond to a device's I/O Port or MMIO space backed BARs.
+ */
+ if (strncmp((const char *)name, "resource", sizeof("resource")-1) == 0)
+ return true;
for (i = 0; i < ARRAY_SIZE(skip); i++)
if (strcmp(name, skip[i]) == 0)
return true;
--
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