Ma Ke make24@iscas.ac.cn writes:
In read_handle(), of_get_address() may return NULL if getting address and size of the node failed. When of_read_number() uses prop to handle conversions between different byte orders, it could lead to a null pointer dereference. Add NULL check to fix potential issue.
Found by static analysis.
Cc: stable@vger.kernel.org Fixes: 14baf4d9c739 ("cxl: Add guest-specific code") Signed-off-by: Ma Ke make24@iscas.ac.cn
Changes in v4:
- modified vulnerability description according to suggestions, making the
process of static analysis of vulnerabilities clearer. No active research on developer behavior. Changes in v3:
- fixed up the changelog text as suggestions.
Changes in v2:
- added an explanation of how the potential vulnerability was discovered,
but not meet the description specification requirements.
drivers/misc/cxl/of.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/misc/cxl/of.c b/drivers/misc/cxl/of.c index bcc005dff1c0..d8dbb3723951 100644 --- a/drivers/misc/cxl/of.c +++ b/drivers/misc/cxl/of.c @@ -58,7 +58,7 @@ static int read_handle(struct device_node *np, u64 *handle) /* Get address and size of the node */ prop = of_get_address(np, 0, &size, NULL);
- if (size)
- if (!prop || size) return -EINVAL;
/* Helper to read a big number; size is in cells (not bytes) */
If you expand the context this could just use of_property_read_reg(), something like below.
cheers
diff --git a/drivers/misc/cxl/of.c b/drivers/misc/cxl/of.c index bcc005dff1c0..a184855b2a7b 100644 --- a/drivers/misc/cxl/of.c +++ b/drivers/misc/cxl/of.c @@ -53,16 +53,15 @@ static const __be64 *read_prop64_dword(const struct device_node *np,
static int read_handle(struct device_node *np, u64 *handle) { - const __be32 *prop; u64 size; + + if (of_property_read_reg(np, 0, handle, &size)) + return -EINVAL;
- /* Get address and size of the node */ - prop = of_get_address(np, 0, &size, NULL); + // Size must be zero per PAPR+ v2.13 ยง C.6.19 if (size) return -EINVAL;
- /* Helper to read a big number; size is in cells (not bytes) */ - *handle = of_read_number(prop, of_n_addr_cells(np)); return 0; }