| Message ID | aa2fd7ae-261a-5c62-821c-96479d11309b@gmail.com (mailing list archive) |
|---|---|
| State | Rejected |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | CRYPTO: Fix initialize 'psp_ret' to avoid uninitialized usage in error paths | expand |
On 11/27/19 6:41 PM, Haiwei Li wrote: > From 842cac9822aafd3cfe2da154b92b033fa1ed0d2d Mon Sep 17 00:00:00 2001 > From: Haiwei Li <lihaiwei@tencent.com> > Date: Thu, 28 Nov 2019 08:25:16 +0800 > Subject: [PATCH] fix: initialize @psp_ret to avoid uninitialized usage > in error paths > > Initialize @psp_ret to -1 to avoid uninitialized usage in error paths. > Such as the function 'sev_flush_asides' in file 'arch/x86/kvm/svm.c'. There is no uninitialized usage in error paths. > > Signed-off-by: Haiwei Li <lihaiwei@tencent.com> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > --- > drivers/crypto/ccp/psp-dev.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c > index 39fdd06..3501562 100644 > --- a/drivers/crypto/ccp/psp-dev.c > +++ b/drivers/crypto/ccp/psp-dev.c > @@ -155,6 +155,9 @@ static int __sev_do_cmd_locked(int cmd, void *data, > int *psp_ret) > unsigned int phys_lsb, phys_msb; > unsigned int reg, ret = 0; > > + if (psp_ret) > + *psp_ret = -1; > + This function is not responsible for initializing memory that comes from elsewhere. Much like the use of errno, we should not modify memory if an error path causes __sev_do_cmd_locked() to return before any work is done. Since this function can return two values (the return code, and the psp_ret argument), it has been defined to use the return value of the function to first indicate success or failure. Only in the case of a failure should the memory pointed to by psp_ret contain any useful information. In every other case, that memory should remain unmodified. The return value that is stored in *psp_ret only represents information from the PSP. Therefore, it should only be modified when the PSP is called. Additionally, there is no "-1" return value from the PSP, and we will not be defining an default value at this time. While I am somewhat sympathetic to the static checker's complaints, the proper solution for that problem is to initialize memory when it is allocated. Not here. Therefore: Nacked-by: Gary R Hook <gary.hook@amd.com> > if (!psp) > return -ENODEV; > > -- > 1.8.3.1
diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c index 39fdd06..3501562 100644 --- a/drivers/crypto/ccp/psp-dev.c +++ b/drivers/crypto/ccp/psp-dev.c @@ -155,6 +155,9 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret) unsigned int phys_lsb, phys_msb; unsigned int reg, ret = 0; + if (psp_ret) + *psp_ret = -1; + if (!psp) return -ENODEV;