ipmi: msghandler: Fix potential Spectre v1 vulnerabilities (a7102c74) · Commits · 戴 / test

channel and addr->channel are indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. These issues were detected with the help of Smatch: drivers/char/ipmi/ipmi_msghandler.c:1381 ipmi_set_my_address() warn: potential spectre issue 'user->intf->addrinfo' [w] (local cap) drivers/char/ipmi/ipmi_msghandler.c:1401 ipmi_get_my_address() warn: potential spectre issue 'user->intf->addrinfo' [r] (local cap) drivers/char/ipmi/ipmi_msghandler.c:1421 ipmi_set_my_LUN() warn: potential spectre issue 'user->intf->addrinfo' [w] (local cap) drivers/char/ipmi/ipmi_msghandler.c:1441 ipmi_get_my_LUN() warn: potential spectre issue 'user->intf->addrinfo' [r] (local cap) drivers/char/ipmi/ipmi_msghandler.c:2260 check_addr() warn: potential spectre issue 'intf->addrinfo' [r] (local cap) Fix this by sanitizing channel and addr->channel before using them to index user->intf->addrinfo and intf->addrinfo, correspondingly. Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/ Cc: stable@vger.kernel.org Signed-off-by:

Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by:

Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/ipmi_msghandler.c

+18 −8

Original line number	Diff line number	Diff line
		@@ -32,6 +32,7 @@
		#include <linux/moduleparam.h>
		#include <linux/workqueue.h>
		#include <linux/uuid.h>
		#include <linux/nospec.h>

		#define IPMI_DRIVER_VERSION "39.2"

		@@ -1298,10 +1299,12 @@ int ipmi_set_my_address(struct ipmi_user *user,
		if (!user)
		return -ENODEV;

		if (channel >= IPMI_MAX_CHANNELS)
		if (channel >= IPMI_MAX_CHANNELS) {
		rv = -EINVAL;
		else
		} else {
		channel = array_index_nospec(channel, IPMI_MAX_CHANNELS);
		user->intf->addrinfo[channel].address = address;
		}
		release_ipmi_user(user, index);

		return rv;
		@@ -1318,10 +1321,12 @@ int ipmi_get_my_address(struct ipmi_user *user,
		if (!user)
		return -ENODEV;

		if (channel >= IPMI_MAX_CHANNELS)
		if (channel >= IPMI_MAX_CHANNELS) {
		rv = -EINVAL;
		else
		} else {
		channel = array_index_nospec(channel, IPMI_MAX_CHANNELS);
		*address = user->intf->addrinfo[channel].address;
		}
		release_ipmi_user(user, index);

		return rv;
		@@ -1338,10 +1343,12 @@ int ipmi_set_my_LUN(struct ipmi_user *user,
		if (!user)
		return -ENODEV;

		if (channel >= IPMI_MAX_CHANNELS)
		if (channel >= IPMI_MAX_CHANNELS) {
		rv = -EINVAL;
		else
		} else {
		channel = array_index_nospec(channel, IPMI_MAX_CHANNELS);
		user->intf->addrinfo[channel].lun = LUN & 0x3;
		}
		release_ipmi_user(user, index);

		return rv;
		@@ -1358,10 +1365,12 @@ int ipmi_get_my_LUN(struct ipmi_user *user,
		if (!user)
		return -ENODEV;

		if (channel >= IPMI_MAX_CHANNELS)
		if (channel >= IPMI_MAX_CHANNELS) {
		rv = -EINVAL;
		else
		} else {
		channel = array_index_nospec(channel, IPMI_MAX_CHANNELS);
		*address = user->intf->addrinfo[channel].lun;
		}
		release_ipmi_user(user, index);

		return rv;
		@@ -2184,6 +2193,7 @@ static int check_addr(struct ipmi_smi *intf,
		{
		if (addr->channel >= IPMI_MAX_CHANNELS)
		return -EINVAL;
		addr->channel = array_index_nospec(addr->channel, IPMI_MAX_CHANNELS);
		*lun = intf->addrinfo[addr->channel].lun;
		*saddr = intf->addrinfo[addr->channel].address;
		return 0;

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