| Message ID | alpine.LRH.2.02.1808221238350.30929@file01.intranet.prod.int.rdu2.redhat.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | dm verity: don't crash on vmallocated buffer | expand |
Hi Mikulas, I have tested the patch. It works. Thanks. Jin On 8/23/2018 12:45 AM, Mikulas Patocka wrote: > Since the commit d1ac3ff008fb ("dm verity: switch to using asynchronous"+ > hash crypto API"), dm-verity uses asynchronous crypto calls for > verification, so that it can use hardware with asynchronous processing of > crypto operations. > > These asynchronous calls don't support vmalloc memory, but the buffer data > can be vmallocated if dm-bufio is short of memory and uses a reserved > buffer that was preallocated in dm_bufio_client_create. > > This patch fixes verity_hash_update, so that it deals with vmallocated > memory correctly. > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > Reported-by: "Xiao, Jin" <jin.xiao@intel.com> > Fixes: d1ac3ff008fb ("dm verity: switch to using asynchronous hash crypto API") > Cc: stable@vger.kernel.org # 4.11+ > > --- > drivers/md/dm-verity-target.c | 24 ++++++++++++++++++++---- > 1 file changed, 20 insertions(+), 4 deletions(-) > > Index: linux-2.6/drivers/md/dm-verity-target.c > =================================================================== > --- linux-2.6.orig/drivers/md/dm-verity-target.c 2018-08-22 17:18:30.800000000 +0200 > +++ linux-2.6/drivers/md/dm-verity-target.c 2018-08-22 17:22:14.810000000 +0200 > @@ -99,10 +99,26 @@ static int verity_hash_update(struct dm_ > { > struct scatterlist sg; > > - sg_init_one(&sg, data, len); > - ahash_request_set_crypt(req, &sg, NULL, len); > - > - return crypto_wait_req(crypto_ahash_update(req), wait); > + if (likely(!is_vmalloc_addr(data))) { > + sg_init_one(&sg, data, len); > + ahash_request_set_crypt(req, &sg, NULL, len); > + return crypto_wait_req(crypto_ahash_update(req), wait); > + } else { > + do { > + int r; > + size_t this_step = min(len, PAGE_SIZE - offset_in_page(data)); > + flush_kernel_vmap_range((void *)data, this_step); > + sg_init_table(&sg, 1); > + sg_set_page(&sg, vmalloc_to_page(data), this_step, offset_in_page(data)); > + ahash_request_set_crypt(req, &sg, NULL, this_step); > + r = crypto_wait_req(crypto_ahash_update(req), wait); > + if (unlikely(r)) > + return r; > + data += this_step; > + len -= this_step; > + } while (len); > + return 0; > + } > } > > /* -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
Index: linux-2.6/drivers/md/dm-verity-target.c =================================================================== --- linux-2.6.orig/drivers/md/dm-verity-target.c 2018-08-22 17:18:30.800000000 +0200 +++ linux-2.6/drivers/md/dm-verity-target.c 2018-08-22 17:22:14.810000000 +0200 @@ -99,10 +99,26 @@ static int verity_hash_update(struct dm_ { struct scatterlist sg; - sg_init_one(&sg, data, len); - ahash_request_set_crypt(req, &sg, NULL, len); - - return crypto_wait_req(crypto_ahash_update(req), wait); + if (likely(!is_vmalloc_addr(data))) { + sg_init_one(&sg, data, len); + ahash_request_set_crypt(req, &sg, NULL, len); + return crypto_wait_req(crypto_ahash_update(req), wait); + } else { + do { + int r; + size_t this_step = min(len, PAGE_SIZE - offset_in_page(data)); + flush_kernel_vmap_range((void *)data, this_step); + sg_init_table(&sg, 1); + sg_set_page(&sg, vmalloc_to_page(data), this_step, offset_in_page(data)); + ahash_request_set_crypt(req, &sg, NULL, this_step); + r = crypto_wait_req(crypto_ahash_update(req), wait); + if (unlikely(r)) + return r; + data += this_step; + len -= this_step; + } while (len); + return 0; + } } /*
Since the commit d1ac3ff008fb ("dm verity: switch to using asynchronous"+ hash crypto API"), dm-verity uses asynchronous crypto calls for verification, so that it can use hardware with asynchronous processing of crypto operations. These asynchronous calls don't support vmalloc memory, but the buffer data can be vmallocated if dm-bufio is short of memory and uses a reserved buffer that was preallocated in dm_bufio_client_create. This patch fixes verity_hash_update, so that it deals with vmallocated memory correctly. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reported-by: "Xiao, Jin" <jin.xiao@intel.com> Fixes: d1ac3ff008fb ("dm verity: switch to using asynchronous hash crypto API") Cc: stable@vger.kernel.org # 4.11+ --- drivers/md/dm-verity-target.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel