WARN on and reject SEV commands that provide a valid data pointer, but do not have a known, non-zero length. And conversely, reject commands that take a command buffer but none is provided (data is null).
Aside from sanity checking input, disallowing a non-null pointer without a non-zero size will allow a future patch to cleanly handle vmalloc'd data by copying the data to an internal __pa() friendly buffer. Note, this also effectively prevents callers from using commands that have a non-zero length and are not known to the kernel. This is not an explicit goal, but arguably the side effect is a good thing from the kernel's perspective. Cc: Brijesh Singh <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Tom Lendacky <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> --- drivers/crypto/ccp/sev-dev.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 3e0d1d6922ba..47a372e07223 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -141,6 +141,7 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret) struct sev_device *sev; unsigned int phys_lsb, phys_msb; unsigned int reg, ret = 0; + int buf_len; if (!psp || !psp->sev_data) return -ENODEV; @@ -150,6 +151,10 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret) sev = psp->sev_data; + buf_len = sev_cmd_buffer_len(cmd); + if (WARN_ON_ONCE(!data != !buf_len)) + return -EINVAL; + if (data && WARN_ON_ONCE(!virt_addr_valid(data))) return -EINVAL; @@ -161,7 +166,7 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret) cmd, phys_msb, phys_lsb, psp_timeout); print_hex_dump_debug("(in): ", DUMP_PREFIX_OFFSET, 16, 2, data, - sev_cmd_buffer_len(cmd), false); + buf_len, false); iowrite32(phys_lsb, sev->io_regs + sev->vdata->cmdbuff_addr_lo_reg); iowrite32(phys_msb, sev->io_regs + sev->vdata->cmdbuff_addr_hi_reg); @@ -197,7 +202,7 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret) } print_hex_dump_debug("(out): ", DUMP_PREFIX_OFFSET, 16, 2, data, - sev_cmd_buffer_len(cmd), false); + buf_len, false); return ret; } -- 2.31.0.208.g409f899ff0-goog
