5.15-stable review patch. If anyone has any objections, please let me know.
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From: King Dix kingdix10@qq.com
[ Upstream commit 2d2da5a4c1b4509f6f7e5a8db015cd420144beb4 ]
The rcar_pcie_parse_outbound_ranges() uses the devm_request_mem_region() macro to request a needed resource. A string variable that lives on the stack is then used to store a dynamically computed resource name, which is then passed on as one of the macro arguments. This can lead to undefined behavior.
Depending on the current contents of the memory, the manifestations of errors may vary. One possible output may be as follows:
$ cat /proc/iomem 30000000-37ffffff : 38000000-3fffffff :
Sometimes, garbage may appear after the colon.
In very rare cases, if no NULL-terminator is found in memory, the system might crash because the string iterator will overrun which can lead to access of unmapped memory above the stack.
Thus, fix this by replacing outbound_name with the name of the previously requested resource. With the changes applied, the output will be as follows:
$ cat /proc/iomem 30000000-37ffffff : memory2 38000000-3fffffff : memory3
Fixes: 2a6d0d63d999 ("PCI: rcar: Add endpoint mode support") Link: https://lore.kernel.org/r/tencent_DBDCC19D60F361119E76919ADAB25EC13C06@qq.co... Tested-by: Lad Prabhakar prabhakar.mahadev-lad.rj@bp.renesas.com Signed-off-by: King Dix kingdix10@qq.com [kwilczynski: commit log] Signed-off-by: Krzysztof Wilczyński kwilczynski@kernel.org Reviewed-by: Lad Prabhakar prabhakar.mahadev-lad.rj@bp.renesas.com Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/controller/pcie-rcar-ep.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c index aa1cf24a5a723..c143ee1740ce7 100644 --- a/drivers/pci/controller/pcie-rcar-ep.c +++ b/drivers/pci/controller/pcie-rcar-ep.c @@ -110,7 +110,7 @@ static int rcar_pcie_parse_outbound_ranges(struct rcar_pcie_endpoint *ep, } if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res), - outbound_name)) { + res->name)) { dev_err(pcie->dev, "Cannot request memory region %s.\n", outbound_name); return -EIO;