From f129430dd87dfe868845292e661b186fbfa89ce3 Mon Sep 17 00:00:00 2001 From: "Leonidas S. Barbosa" Date: Tue, 28 Oct 2014 15:50:45 -0200 Subject: [PATCH] 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 Signed-off-by: Herbert Xu --- drivers/crypto/nx/nx.c | 127 +++++++++++++++++++++++++++++++++++------ drivers/crypto/nx/nx.h | 8 ++- 2 files changed, 113 insertions(+), 22 deletions(-) diff --git a/drivers/crypto/nx/nx.c b/drivers/crypto/nx/nx.c index 5533fe31c90d..a392465d3e3f 100644 --- a/drivers/crypto/nx/nx.c +++ b/drivers/crypto/nx/nx.c @@ -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); diff --git a/drivers/crypto/nx/nx.h b/drivers/crypto/nx/nx.h index befda07ca1da..6c9ecaaead52 100644 --- a/drivers/crypto/nx/nx.h +++ b/drivers/crypto/nx/nx.h @@ -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) -- 2.30.2