From: David Rientjes rientjes@google.com
[ Upstream commit 91dfd98216d817ec5f1c55890bacb7b4fe9b068a ]
For SEV_GET_ID2, the user provided length does not have a specified limitation because the length of the ID may change in the future. The kernel memory allocation, however, is implicitly limited to 4MB on x86 by the page allocator, otherwise the kzalloc() will fail.
When this happens, it is best not to spam the kernel log with the warning. Simply fail the allocation and return ENOMEM to the user.
Fixes: d6112ea0cb34 ("crypto: ccp - introduce SEV_GET_ID2 command") Reported-by: Andy Nguyen theflow@google.com Reported-by: Peter Gonda pgonda@google.com Suggested-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: David Rientjes rientjes@google.com Acked-by: Tom Lendacky thomas.lendacky@amd.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/crypto/ccp/sev-dev.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 900727b5edda5..15ef60cd4b149 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -667,7 +667,14 @@ static int sev_ioctl_do_get_id2(struct sev_issue_cmd *argp) input_address = (void __user *)input.address;
if (input.address && input.length) { - id_blob = kzalloc(input.length, GFP_KERNEL); + /* + * The length of the ID shouldn't be assumed by software since + * it may change in the future. The allocation size is limited + * to 1 << (PAGE_SHIFT + MAX_ORDER - 1) by the page allocator. + * If the allocation fails, simply return ENOMEM rather than + * warning in the kernel log. + */ + id_blob = kzalloc(input.length, GFP_KERNEL | __GFP_NOWARN); if (!id_blob) return -ENOMEM;