Skip to content

misc: fastrpc: avoid duplicate DMA mappings in fastrpc_create_maps() #774

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Jianping-Li wants to merge 2 commits into
base: qcom-6.18.y
Choose a base branch
from
+21 −24
Open

misc: fastrpc: avoid duplicate DMA mappings in fastrpc_create_maps() #774

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
9a36fb2
BACKPORT: misc: fastrpc: fix use-after-free race in fastrpc_map_create
reyn-osec May 30, 2026
eeca32c
FROMLIST: misc: fastrpc: avoid duplicate DMA mappings in fastrpc_crea…
Jianping-Li Jun 25, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
45 changes: 21 additions & 24 deletions drivers/misc/fastrpc.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -392,7 +392,7 @@ static int fastrpc_map_get(struct fastrpc_map *map)


static int fastrpc_map_lookup(struct fastrpc_user *fl, int fd,
struct fastrpc_map **ppmap)
struct fastrpc_map **ppmap, bool take_ref)
{
struct fastrpc_map *map = NULL;
struct dma_buf *buf;
Expand All @@ -407,6 +407,12 @@ static int fastrpc_map_lookup(struct fastrpc_user *fl, int fd,
if (map->fd != fd || map->buf != buf)
continue;

if (take_ref) {
ret = fastrpc_map_get(map);
if (ret)
break;
}

*ppmap = map;
ret = 0;
break;
Expand Down Expand Up @@ -955,21 +961,12 @@ static int fastrpc_map_attach(struct fastrpc_user *fl, int fd,
}

static int fastrpc_map_create(struct fastrpc_user *fl, int fd,
u64 len, u32 attr, struct fastrpc_map **ppmap)
u64 len, u32 attr, struct fastrpc_map **ppmap, bool take_ref)
{
struct fastrpc_session_ctx *sess = fl->sctx;
int err = 0;
if (!fastrpc_map_lookup(fl, fd, ppmap, take_ref))
return 0;

if (!fastrpc_map_lookup(fl, fd, ppmap)) {
if (!fastrpc_map_get(*ppmap))
return 0;
dev_dbg(sess->dev, "%s: Failed to get map fd=%d\n",
__func__, fd);
}

err = fastrpc_map_attach(fl, fd, len, attr, ppmap);

return err;
return fastrpc_map_attach(fl, fd, len, attr, ppmap);
}

/*
Expand Down Expand Up @@ -1040,23 +1037,23 @@ static int fastrpc_create_maps(struct fastrpc_invoke_ctx *ctx)
int i, err;

for (i = 0; i < ctx->nscalars; ++i) {
bool take_ref = true;

if (ctx->args[i].fd == 0 || ctx->args[i].fd == -1 ||
ctx->args[i].length == 0)
continue;

if (i < ctx->nbufs)
err = fastrpc_map_create(ctx->fl, ctx->args[i].fd,
ctx->args[i].length, ctx->args[i].attr, &ctx->maps[i]);
else
err = fastrpc_map_attach(ctx->fl, ctx->args[i].fd,
ctx->args[i].length, ctx->args[i].attr, &ctx->maps[i]);
if (i >= ctx->nbufs)
take_ref = false;

err = fastrpc_map_create(ctx->fl, ctx->args[i].fd, ctx->args[i].length,
ctx->args[i].attr, &ctx->maps[i], take_ref);
if (err) {
dev_err(dev, "Error Creating map %d\n", err);
return -EINVAL;
}

}

return 0;
}

Expand Down Expand Up @@ -1298,7 +1295,7 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
for (i = 0; i < FASTRPC_MAX_FDLIST; i++) {
if (!fdlist[i])
break;
if (!fastrpc_map_lookup(fl, (int)fdlist[i], &mmap))
if (!fastrpc_map_lookup(fl, (int)fdlist[i], &mmap, false))
fastrpc_map_put(mmap);
}

Expand Down Expand Up @@ -1651,7 +1648,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl,
fl->pd = USER_PD;

if (init.filelen && init.filefd) {
err = fastrpc_map_create(fl, init.filefd, init.filelen, 0, &map);
err = fastrpc_map_create(fl, init.filefd, init.filelen, 0, &map, true);
if (err)
goto err;
}
Expand Down Expand Up @@ -2278,7 +2275,7 @@ static int fastrpc_req_mem_map(struct fastrpc_user *fl, char __user *argp)
return -EFAULT;

/* create SMMU mapping */
err = fastrpc_map_create(fl, req.fd, req.length, 0, &map);
err = fastrpc_map_create(fl, req.fd, req.length, 0, &map, true);
if (err) {
dev_err(dev, "failed to map buffer, fd = %d\n", req.fd);
return err;
Expand Down