cifs: fix possible uninitialized access and race on iface_list (9a7d5a9e) · Commits · 戴 / test

fs/cifs/sess.c

+26 −3

Original line number	Diff line number	Diff line
		@@ -77,6 +77,8 @@ int cifs_try_adding_channels(struct cifs_ses *ses)
		int i = 0;
		int rc = 0;
		int tries = 0;
		struct cifs_server_iface *ifaces = NULL;
		size_t iface_count;

		if (left <= 0) {
		cifs_dbg(FYI,
		@@ -90,6 +92,26 @@ int cifs_try_adding_channels(struct cifs_ses *ses)
		return 0;
		}

		/*
		* Make a copy of the iface list at the time and use that
		* instead so as to not hold the iface spinlock for opening
		* channels
		*/
		spin_lock(&ses->iface_lock);
		iface_count = ses->iface_count;
		if (iface_count <= 0) {
		spin_unlock(&ses->iface_lock);
		cifs_dbg(FYI, "no iface list available to open channels\n");
		return 0;
		}
		ifaces = kmemdup(ses->iface_list, iface_countsizeof(ifaces),
		GFP_ATOMIC);
		if (!ifaces) {
		spin_unlock(&ses->iface_lock);
		return 0;
		}
		spin_unlock(&ses->iface_lock);

		/*
		* Keep connecting to same, fastest, iface for all channels as
		* long as its RSS. Try next fastest one if not RSS or channel
		@@ -105,9 +127,9 @@ int cifs_try_adding_channels(struct cifs_ses *ses)
		break;
		}

		iface = &ses->iface_list[i];
		iface = &ifaces[i];
		if (is_ses_using_iface(ses, iface) && !iface->rss_capable) {
		i = (i+1) % ses->iface_count;
		i = (i+1) % iface_count;
		continue;
		}

		@@ -115,7 +137,7 @@ int cifs_try_adding_channels(struct cifs_ses *ses)
		if (rc) {
		cifs_dbg(FYI, "failed to open extra channel on iface#%d rc=%d\n",
		i, rc);
		i = (i+1) % ses->iface_count;
		i = (i+1) % iface_count;
		continue;
		}

		@@ -124,6 +146,7 @@ int cifs_try_adding_channels(struct cifs_ses *ses)
		left--;
		}

		kfree(ifaces);
		return ses->chan_count - old_chan_count;
		}

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