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crypto: ccp/sev-dev-tsm - bail out early when pdev->bus is NULL

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dsm_create() initially checks pdev->bus when computing segment_id:

	u8 segment_id = pdev->bus ? pci_domain_nr(pdev->bus) : 0;

But the next two lines unconditionally dereference pdev->bus via
pcie_find_root_port() and especially pci_dev_id(pdev), which expands
to PCI_DEVID(dev->bus->number, dev->devfn). If pdev->bus is in fact
NULL, segment_id is initialised to 0 but the very next statement
crashes the kernel.

smatch flags this:

  drivers/crypto/ccp/sev-dev-tsm.c:253 dsm_create() error: we
    previously assumed 'pdev->bus' could be null (see line 251)

Make the NULL handling consistent: if pdev->bus is NULL the device
has no PCI context to work with and SEV TIO setup cannot proceed,
so return -ENODEV before any of the bus-dependent lookups. The
remaining initialisation now runs only on the path where pdev->bus
is known to be valid.

No change for callers where pdev->bus is non-NULL, which is the
only case where dsm_create() did meaningful work before this change.

Fixes: 4be423572d ("crypto/ccp: Implement SEV-TIO PCIe IDE (phase1)")
Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Stepan Ionichev
2026-05-07 19:06:08 +05:00
committed by Herbert Xu
parent 5b085b2a03
commit 930d9d36ea
1 changed files with 10 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/crypto/ccp/sev-dev-tsm.c
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@@ -248,12 +248,19 @@ static void dsm_remove(struct pci_tsm *tsm)
static int dsm_create(struct tio_dsm *dsm)
{
struct pci_dev *pdev = dsm->tsm.base_tsm.pdev;
u8 segment_id = pdev->bus ? pci_domain_nr(pdev->bus) : 0;
struct pci_dev *rootport = pcie_find_root_port(pdev);
u16 device_id = pci_dev_id(pdev);
struct pci_dev *rootport;
u8 segment_id;
u16 device_id;
u16 root_port_id;
u32 lnkcap = 0;
if (!pdev->bus)
return -ENODEV;
segment_id = pci_domain_nr(pdev->bus);
rootport = pcie_find_root_port(pdev);
device_id = pci_dev_id(pdev);
if (pci_read_config_dword(rootport, pci_pcie_cap(rootport) + PCI_EXP_LNKCAP,
&lnkcap))
return -ENODEV;