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FROMLIST: misc: fastrpc: fix UAF and kernel panic during cleanup on process abort #1032

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FROMLIST: misc: fastrpc: fix UAF and kernel panic during cleanup on process abort #1032

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56 changes: 51 additions & 5 deletions drivers/misc/fastrpc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -271,6 +271,8 @@ struct fastrpc_session_ctx {
int sid;
bool used;
bool valid;
bool allocated;
struct mutex mutex;
};

struct fastrpc_soc_data {
Expand Down Expand Up @@ -353,9 +355,14 @@ static inline u64 fastrpc_sid_offset(struct fastrpc_channel_ctx *cctx,
static void fastrpc_free_map(struct kref *ref)
{
struct fastrpc_map *map;
struct fastrpc_user *fl;

map = container_of(ref, struct fastrpc_map, refcount);

fl = map->fl;
if (!fl)
return;

if (map->table) {
if (map->attr & FASTRPC_ATTR_SECUREMAP) {
struct qcom_scm_vmperm perm;
Expand All @@ -374,10 +381,16 @@ static void fastrpc_free_map(struct kref *ref)
return;
}
}
mutex_lock(&fl->sctx->mutex);
if (!fl->sctx->dev) {
mutex_unlock(&fl->sctx->mutex);
return;
}
dma_buf_unmap_attachment_unlocked(map->attach, map->table,
DMA_BIDIRECTIONAL);
dma_buf_detach(map->buf, map->attach);
dma_buf_put(map->buf);
mutex_unlock(&fl->sctx->mutex);
}

if (map->fl) {
Expand Down Expand Up @@ -434,9 +447,17 @@ static int fastrpc_map_lookup(struct fastrpc_user *fl, int fd,

static void fastrpc_buf_free(struct fastrpc_buf *buf)
{
dma_free_coherent(buf->dev, buf->size, buf->virt,
fastrpc_ipa_to_dma_addr(buf->fl->cctx, buf->dma_addr));
kfree(buf);
struct fastrpc_user *fl = buf->fl;

if (!fl)
return;
mutex_lock(&fl->sctx->mutex);
if (fl->sctx->dev) {
dma_free_coherent(buf->dev, buf->size, buf->virt,
FASTRPC_PHYS(buf->phys));
kfree(buf);
}
mutex_unlock(&fl->sctx->mutex);
}

static int __fastrpc_buf_alloc(struct fastrpc_user *fl, struct device *dev,
Expand All @@ -459,8 +480,10 @@ static int __fastrpc_buf_alloc(struct fastrpc_user *fl, struct device *dev,
buf->dev = dev;
buf->raddr = 0;

buf->virt = dma_alloc_coherent(dev, buf->size, &buf->dma_addr,
GFP_KERNEL);
mutex_lock(&fl->sctx->mutex);
if (fl->sctx->dev)
buf->virt = dma_alloc_coherent(dev, buf->size, (dma_addr_t *)&buf->phys, GFP_KERNEL);
mutex_unlock(&fl->sctx->mutex);
if (!buf->virt) {
mutex_destroy(&buf->lock);
kfree(buf);
Expand Down Expand Up @@ -503,6 +526,10 @@ static void fastrpc_channel_ctx_free(struct kref *ref)
struct fastrpc_channel_ctx *cctx;

cctx = container_of(ref, struct fastrpc_channel_ctx, refcount);
for (int i = 0; i < FASTRPC_MAX_SESSIONS; i++) {
if (cctx->session[i].allocated)
mutex_destroy(&cctx->session[i].mutex);
}

kfree(cctx);
}
Expand Down Expand Up @@ -846,19 +873,29 @@ static int fastrpc_map_attach(struct fastrpc_user *fl, int fd,
goto get_err;
}

mutex_lock(&fl->sctx->mutex);
if (!fl->sctx->dev) {
err = -ENODEV;
mutex_unlock(&fl->sctx->mutex);
goto attach_err;
}

map->attach = dma_buf_attach(map->buf, sess->dev);
if (IS_ERR(map->attach)) {
dev_err(sess->dev, "Failed to attach dmabuf\n");
err = PTR_ERR(map->attach);
mutex_unlock(&fl->sctx->mutex);
goto attach_err;
}

table = dma_buf_map_attachment_unlocked(map->attach, DMA_BIDIRECTIONAL);
if (IS_ERR(table)) {
err = PTR_ERR(table);
mutex_unlock(&fl->sctx->mutex);
goto map_err;
}
map->table = table;
mutex_unlock(&fl->sctx->mutex);

if (attr & FASTRPC_ATTR_SECUREMAP)
map->dma_addr = sg_phys(map->table->sgl);
Expand Down Expand Up @@ -2364,6 +2401,8 @@ static int fastrpc_cb_probe(struct platform_device *pdev)
sess->used = false;
sess->valid = true;
sess->dev = dev;
mutex_init(&sess->mutex);
sess->allocated = true;
dev_set_drvdata(dev, sess);

if (cctx->domain_id == CDSP_DOMAIN_ID)
Expand All @@ -2380,6 +2419,8 @@ static int fastrpc_cb_probe(struct platform_device *pdev)
break;
dup_sess = &cctx->session[cctx->sesscount++];
memcpy(dup_sess, sess, sizeof(*dup_sess));
mutex_init(&dup_sess->mutex);
dup_sess->allocated = true;
}
}
spin_unlock_irqrestore(&cctx->lock, flags);
Expand All @@ -2402,6 +2443,11 @@ static void fastrpc_cb_remove(struct platform_device *pdev)
spin_lock_irqsave(&cctx->lock, flags);
for (i = 0; i < FASTRPC_MAX_SESSIONS; i++) {
if (cctx->session[i].sid == sess->sid) {
spin_unlock_irqrestore(&cctx->lock, flags);
mutex_lock(&cctx->session[i].mutex);
cctx->session[i].dev = NULL;
mutex_unlock(&cctx->session[i].mutex);
spin_lock_irqsave(&cctx->lock, flags);
cctx->session[i].valid = false;
cctx->sesscount--;
}
Expand Down