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crypto: nx - Fixing the limit number of bytes to be processed 

The previous limits were estimated locally in a single step
basead on bound values, however it was not correct since
when given certain scatterlist the function nx_build_sg_lists
was consuming more sg entries than allocated causing a
memory corruption and crashes.

e.g.: in the worst case we could have one sg entry for a single byte.

This patch fixes it modifying the logic of the bound limit
moving it to nx_sg_build_lists and set a correct sg_max limit,
adding a trim function to ensure the bound in sg_list. Also fixing
nx_build_sg_list  NULL and untreated return in case of overflow.

Signed-off-by: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Leonidas S. Barbosa 2014-10-28 15:50:45 -02:00 committed by Herbert Xu
parent 000851119e
commit f129430dd8
2 changed files with 113 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

127
drivers/crypto/nx/nx.c
View File

@ -90,7 +90,7 @@ int nx_hcall_sync(struct nx_crypto_ctx *nx_ctx,
*/
struct nx_sg *nx_build_sg_list(struct nx_sg *sg_head,
u8 *start_addr,
unsigned int len,
unsigned int *len,
u32 sgmax)
{
unsigned int sg_len = 0;
@ -106,7 +106,7 @@ struct nx_sg *nx_build_sg_list(struct nx_sg *sg_head,
else
sg_addr = __pa(sg_addr);
end_addr = sg_addr + len;
end_addr = sg_addr + *len;
/* each iteration will write one struct nx_sg element and add the
* length of data described by that element to sg_len. Once @len bytes
@ -118,7 +118,7 @@ struct nx_sg *nx_build_sg_list(struct nx_sg *sg_head,
* Also when using vmalloc'ed data, every time that a system page
* boundary is crossed the physical address needs to be re-calculated.
*/
for (sg = sg_head; sg_len < len; sg++) {
for (sg = sg_head; sg_len < *len; sg++) {
u64 next_page;
sg->addr = sg_addr;
@ -133,15 +133,17 @@ struct nx_sg *nx_build_sg_list(struct nx_sg *sg_head,
is_vmalloc_addr(start_addr + sg_len)) {
sg_addr = page_to_phys(vmalloc_to_page(
start_addr + sg_len));
end_addr = sg_addr + len - sg_len;
end_addr = sg_addr + *len - sg_len;
}
if ((sg - sg_head) == sgmax) {
pr_err("nx: scatter/gather list overflow, pid: %d\n",
current->pid);
return NULL;
sg++;
break;
}
}
*len = sg_len;
/* return the moved sg_head pointer */
return sg;
@ -160,11 +162,11 @@ struct nx_sg *nx_walk_and_build(struct nx_sg *nx_dst,
unsigned int sglen,
struct scatterlist *sg_src,
unsigned int start,
unsigned int src_len)
unsigned int *src_len)
{
struct scatter_walk walk;
struct nx_sg *nx_sg = nx_dst;
unsigned int n, offset = 0, len = src_len;
unsigned int n, offset = 0, len = *src_len;
char *dst;
/* we need to fast forward through @start bytes first */
@ -182,26 +184,100 @@ struct nx_sg *nx_walk_and_build(struct nx_sg *nx_dst,
* element we're currently looking at */
scatterwalk_advance(&walk, start - offset);
while (len && nx_sg) {
while (len && (nx_sg - nx_dst) < sglen) {
n = scatterwalk_clamp(&walk, len);
if (!n) {
scatterwalk_start(&walk, sg_next(walk.sg));
/* In cases where we have scatterlist chain scatterwalk_sg_next
* handles with it properly */
scatterwalk_start(&walk, scatterwalk_sg_next(walk.sg));
n = scatterwalk_clamp(&walk, len);
}
dst = scatterwalk_map(&walk);
nx_sg = nx_build_sg_list(nx_sg, dst, n, sglen);
nx_sg = nx_build_sg_list(nx_sg, dst, &n, sglen - (nx_sg - nx_dst));
len -= n;
scatterwalk_unmap(dst);
scatterwalk_advance(&walk, n);
scatterwalk_done(&walk, SCATTERWALK_FROM_SG, len);
}
/* update to_process */
*src_len -= len;
/* return the moved destination pointer */
return nx_sg;
}
/**
* trim_sg_list - ensures the bound in sg list.
* @sg: sg list head
* @end: sg lisg end
* @delta: is the amount we need to crop in order to bound the list.
*
*/
static long int trim_sg_list(struct nx_sg *sg, struct nx_sg *end, unsigned int delta)
{
while (delta && end > sg) {
struct nx_sg *last = end - 1;
if (last->len > delta) {
last->len -= delta;
delta = 0;
} else {
end--;
delta -= last->len;
}
}
return (sg - end) * sizeof(struct nx_sg);
}
/**
* nx_sha_build_sg_list - walk and build sg list to sha modes
* using right bounds and limits.
* @nx_ctx: NX crypto context for the lists we're building
* @nx_sg: current sg list in or out list
* @op_len: current op_len to be used in order to build a sg list
* @nbytes: number or bytes to be processed
* @offset: buf offset
* @mode: SHA256 or SHA512
*/
int nx_sha_build_sg_list(struct nx_crypto_ctx *nx_ctx,
struct nx_sg *nx_in_outsg,
s64 *op_len,
unsigned int *nbytes,
u8 *offset,
u32 mode)
{
unsigned int delta = 0;
unsigned int total = *nbytes;
struct nx_sg *nx_insg = nx_in_outsg;
unsigned int max_sg_len;
max_sg_len = min_t(u64, nx_ctx->ap->sglen,
nx_driver.of.max_sg_len/sizeof(struct nx_sg));
max_sg_len = min_t(u64, max_sg_len,
nx_ctx->ap->databytelen/NX_PAGE_SIZE);
*nbytes = min_t(u64, *nbytes, nx_ctx->ap->databytelen);
nx_insg = nx_build_sg_list(nx_insg, offset, nbytes, max_sg_len);
switch (mode) {
case NX_DS_SHA256:
if (*nbytes < total)
delta = *nbytes - (*nbytes & ~(SHA256_BLOCK_SIZE - 1));
break;
case NX_DS_SHA512:
if (*nbytes < total)
delta = *nbytes - (*nbytes & ~(SHA512_BLOCK_SIZE - 1));
break;
default:
return -EINVAL;
}
*op_len = trim_sg_list(nx_in_outsg, nx_insg, delta);
return 0;
}
/**
* nx_build_sg_lists - walk the input scatterlists and build arrays of NX
* scatterlists based on them.
@ -223,26 +299,39 @@ int nx_build_sg_lists(struct nx_crypto_ctx *nx_ctx,
struct blkcipher_desc *desc,
struct scatterlist *dst,
struct scatterlist *src,
unsigned int nbytes,
unsigned int *nbytes,
unsigned int offset,
u8 *iv)
{
unsigned int delta = 0;
unsigned int total = *nbytes;
struct nx_sg *nx_insg = nx_ctx->in_sg;
struct nx_sg *nx_outsg = nx_ctx->out_sg;
unsigned int max_sg_len;
max_sg_len = min_t(u64, nx_ctx->ap->sglen,
nx_driver.of.max_sg_len/sizeof(struct nx_sg));
max_sg_len = min_t(u64, max_sg_len,
nx_ctx->ap->databytelen/NX_PAGE_SIZE);
if (iv)
memcpy(iv, desc->info, AES_BLOCK_SIZE);
nx_insg = nx_walk_and_build(nx_insg, nx_ctx->ap->sglen, src,
offset, nbytes);
nx_outsg = nx_walk_and_build(nx_outsg, nx_ctx->ap->sglen, dst,
offset, nbytes);
*nbytes = min_t(u64, *nbytes, nx_ctx->ap->databytelen);
nx_outsg = nx_walk_and_build(nx_outsg, max_sg_len, dst,
offset, nbytes);
nx_insg = nx_walk_and_build(nx_insg, max_sg_len, src,
offset, nbytes);
if (*nbytes < total)
delta = *nbytes - (*nbytes & ~(AES_BLOCK_SIZE - 1));
/* these lengths should be negative, which will indicate to phyp that
* the input and output parameters are scatterlists, not linear
* buffers */
nx_ctx->op.inlen = (nx_ctx->in_sg - nx_insg) * sizeof(struct nx_sg);
nx_ctx->op.outlen = (nx_ctx->out_sg - nx_outsg) * sizeof(struct nx_sg);
nx_ctx->op.inlen = trim_sg_list(nx_ctx->in_sg, nx_insg, delta);
nx_ctx->op.outlen = trim_sg_list(nx_ctx->out_sg, nx_outsg, delta);
return 0;
}
@ -540,10 +629,10 @@ static int nx_crypto_ctx_init(struct nx_crypto_ctx *nx_ctx, u32 fc, u32 mode)
/* we need an extra page for csbcpb_aead for these modes */
if (mode == NX_MODE_AES_GCM || mode == NX_MODE_AES_CCM)
nx_ctx->kmem_len = (4 * NX_PAGE_SIZE) +
nx_ctx->kmem_len = (5 * NX_PAGE_SIZE) +
sizeof(struct nx_csbcpb);
else
nx_ctx->kmem_len = (3 * NX_PAGE_SIZE) +
nx_ctx->kmem_len = (4 * NX_PAGE_SIZE) +
sizeof(struct nx_csbcpb);
nx_ctx->kmem = kmalloc(nx_ctx->kmem_len, GFP_KERNEL);

8
drivers/crypto/nx/nx.h
View File

@ -153,13 +153,15 @@ void nx_crypto_ctx_exit(struct crypto_tfm *tfm);
void nx_ctx_init(struct nx_crypto_ctx *nx_ctx, unsigned int function);
int nx_hcall_sync(struct nx_crypto_ctx *ctx, struct vio_pfo_op *op,
u32 may_sleep);
struct nx_sg *nx_build_sg_list(struct nx_sg *, u8 *, unsigned int, u32);
int nx_sha_build_sg_list(struct nx_crypto_ctx *, struct nx_sg *,
s64 *, unsigned int *, u8 *, u32);
struct nx_sg *nx_build_sg_list(struct nx_sg *, u8 *, unsigned int *, u32);
int nx_build_sg_lists(struct nx_crypto_ctx *, struct blkcipher_desc *,
struct scatterlist *, struct scatterlist *, unsigned int,
struct scatterlist *, struct scatterlist *, unsigned int *,
unsigned int, u8 *);
struct nx_sg *nx_walk_and_build(struct nx_sg *, unsigned int,
struct scatterlist *, unsigned int,
unsigned int);
unsigned int *);
#ifdef CONFIG_DEBUG_FS
#define NX_DEBUGFS_INIT(drv) nx_debugfs_init(drv)