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Commit 9d43774c authored by Himateja Reddy's avatar Himateja Reddy
Browse files

msm: adsprpc: allow only unsigned offload for untrusted apps 



Restrict untrusted third-party applications to only unsigned PD
offload on the remote subsystem. This is done by comparing PID at
the time of process create with the one stored during device open
as the fastrpc device will be opened by DSP HAL service on behalf
of third-party applications.

Change-Id: Ibaead21a429e6bffe8f0808eebf93bf71d1db7ab
Acked-by: default avatarThyagarajan Venkatanarayanan <venkatan@qti.qualcomm.com>
Signed-off-by: default avatarHimateja Reddy <hmreddy@codeaurora.org>
parent bca5c0ff

drivers/char/adsprpc.c

+24 −3
Original line number Diff line number Diff line
@@ -179,8 +179,11 @@ 
#define INIT_MEMLEN_MAX  (8*1024*1024)

#define MAX_CACHE_BUF_SIZE (8*1024*1024)



/* Position of privilege bit in remote process attribute */

#define FASTRPC_MODE_PRIVILEGED		(1 << 6)

/* Fastrpc remote process attributes */

enum fastrpc_proc_attr {

	FASTRPC_MODE_UNSIGNED_MODULE = (1 << 3),

	FASTRPC_MODE_PRIVILEGED      = (1 << 6),

};



#define PERF_END (void)0
@@ -492,7 +495,8 @@ struct fastrpc_file { 
	uint32_t mode;

	uint32_t profile;

	int sessionid;

	int tgid;

	int tgid_open;	/* Process ID during device open */

	int tgid;		/* Process ID that uses device for RPC calls */

	int cid;

	uint64_t ssrcount;

	int pd;
@@ -2810,6 +2814,22 @@ static int fastrpc_init_create_dynamic_process(struct fastrpc_file *fl, 
	}

	inbuf.pageslen = 1;



	/*

	 * Third-party apps don't have permission to open the fastrpc device, so

	 * it is opened on their behalf by a trusted process. Such untrusted

	 * apps are not allowed to offload to signedPD on DSP. This is detected

	 * by comparing current PID with the one stored during device open.

	 */

	if (fl->tgid != fl->tgid_open) {

		VERIFY(err, uproc->attrs & FASTRPC_MODE_UNSIGNED_MODULE);

		if (err) {

			err = -EINVAL;

			pr_err("Error: adsprpc: %s: %s: untrusted app trying to offload to signed remote process\n",

				__func__, current->comm);

			goto bail;

		}

	}



	/* Disregard any privilege bits from userspace */

	uproc->attrs &= (~FASTRPC_MODE_PRIVILEGED);
@@ -4388,6 +4408,7 @@ static int fastrpc_device_open(struct inode *inode, struct file *filp) 
	init_waitqueue_head(&fl->async_wait_queue);

	INIT_HLIST_NODE(&fl->hn);

	fl->sessionid = 0;

	fl->tgid_open = current->tgid;

	fl->apps = me;

	fl->mode = FASTRPC_MODE_SERIAL;

	fl->cid = -1;