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Commit 753abe2a authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Greg Kroah-Hartman
Browse files

ipmi: msghandler: Fix potential Spectre v1 vulnerabilities 

commit a7102c7461794a5bb31af24b08e9e0f50038897a upstream.

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: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1c393ca1

drivers/char/ipmi/ipmi_msghandler.c

+18 −8
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/moduleparam.h>

#include <linux/workqueue.h>

#include <linux/uuid.h>

#include <linux/nospec.h>



#define PFX "IPMI message handler: "
@@ -1297,10 +1298,12 @@ 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;
@@ -1317,10 +1320,12 @@ 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;
@@ -1337,10 +1342,12 @@ 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 0;
@@ -1357,10 +1364,12 @@ 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;