The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 8b5b456222fd604079b5cf2af1f25ad690f54a25 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025101329-freestyle-unfair-5d44@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8b5b456222fd604079b5cf2af1f25ad690f54a25 Mon Sep 17 00:00:00 2001 From: Ling Xu quic_lxu5@quicinc.com Date: Fri, 12 Sep 2025 14:12:33 +0100 Subject: [PATCH] misc: fastrpc: Save actual DMA size in fastrpc_map structure

For user passed fd buffer, map is created using DMA calls. The map related information is stored in fastrpc_map structure. The actual DMA size is not stored in the structure. Store the actual size of buffer and check it against the user passed size.

Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Cc: stable@kernel.org Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@oss.qualcomm.com Co-developed-by: Ekansh Gupta ekansh.gupta@oss.qualcomm.com Signed-off-by: Ekansh Gupta ekansh.gupta@oss.qualcomm.com Signed-off-by: Ling Xu quic_lxu5@quicinc.com Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Srinivas Kandagatla srini@kernel.org Link: https://lore.kernel.org/r/20250912131236.303102-2-srini@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 53e88a1bc430..52571916acd4 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -323,11 +323,11 @@ static void fastrpc_free_map(struct kref *ref)

perm.vmid = QCOM_SCM_VMID_HLOS; perm.perm = QCOM_SCM_PERM_RWX; - err = qcom_scm_assign_mem(map->phys, map->size, + err = qcom_scm_assign_mem(map->phys, map->len, &src_perms, &perm, 1); if (err) { dev_err(map->fl->sctx->dev, "Failed to assign memory phys 0x%llx size 0x%llx err %d\n", - map->phys, map->size, err); + map->phys, map->len, err); return; } } @@ -758,7 +758,8 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd, struct fastrpc_session_ctx *sess = fl->sctx; struct fastrpc_map *map = NULL; struct sg_table *table; - int err = 0; + struct scatterlist *sgl = NULL; + int err = 0, sgl_index = 0;

if (!fastrpc_map_lookup(fl, fd, ppmap, true)) return 0; @@ -798,7 +799,15 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd, map->phys = sg_dma_address(map->table->sgl); map->phys += ((u64)fl->sctx->sid << 32); } - map->size = len; + for_each_sg(map->table->sgl, sgl, map->table->nents, + sgl_index) + map->size += sg_dma_len(sgl); + if (len > map->size) { + dev_dbg(sess->dev, "Bad size passed len 0x%llx map size 0x%llx\n", + len, map->size); + err = -EINVAL; + goto map_err; + } map->va = sg_virt(map->table->sgl); map->len = len;

@@ -815,10 +824,10 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd, dst_perms[1].vmid = fl->cctx->vmperms[0].vmid; dst_perms[1].perm = QCOM_SCM_PERM_RWX; map->attr = attr; - err = qcom_scm_assign_mem(map->phys, (u64)map->size, &src_perms, dst_perms, 2); + err = qcom_scm_assign_mem(map->phys, (u64)map->len, &src_perms, dst_perms, 2); if (err) { dev_err(sess->dev, "Failed to assign memory with phys 0x%llx size 0x%llx err %d\n", - map->phys, map->size, err); + map->phys, map->len, err); goto map_err; } } @@ -2046,7 +2055,7 @@ static int fastrpc_req_mem_map(struct fastrpc_user *fl, char __user *argp) args[0].length = sizeof(req_msg);

pages.addr = map->phys; - pages.size = map->size; + pages.size = map->len;

args[1].ptr = (u64) (uintptr_t) &pages; args[1].length = sizeof(pages); @@ -2061,7 +2070,7 @@ static int fastrpc_req_mem_map(struct fastrpc_user *fl, char __user *argp) err = fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE, sc, &args[0]); if (err) { dev_err(dev, "mem mmap error, fd %d, vaddr %llx, size %lld\n", - req.fd, req.vaddrin, map->size); + req.fd, req.vaddrin, map->len); goto err_invoke; }

@@ -2074,7 +2083,7 @@ static int fastrpc_req_mem_map(struct fastrpc_user *fl, char __user *argp) if (copy_to_user((void __user *)argp, &req, sizeof(req))) { /* unmap the memory and release the buffer */ req_unmap.vaddr = (uintptr_t) rsp_msg.vaddr; - req_unmap.length = map->size; + req_unmap.length = map->len; fastrpc_req_mem_unmap_impl(fl, &req_unmap); return -EFAULT; }