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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2019-01-09 13:02:36 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-18 16:42:05 +0100 |
| commit | 701956d4018e5d5438570e39e8bda47edd32c489 (patch) | |
| tree | c7b11f53a12774d449a5a9fb6781814d5ee8929c /drivers/char | |
| parent | e25df7812c91f62581301f9a7ac102acf92e4937 (diff) | |
| download | linux-701956d4018e5d5438570e39e8bda47edd32c489.tar.gz | |
char/mwave: fix potential Spectre v1 vulnerability
ipcnum is indirectly controlled by user-space, hence leading to
a potential exploitation of the Spectre variant 1 vulnerability.
This issue was detected with the help of Smatch:
drivers/char/mwave/mwavedd.c:299 mwave_ioctl() warn: potential spectre issue 'pDrvData->IPCs' [w] (local cap)
Fix this by sanitizing ipcnum before using it to index pDrvData->IPCs.
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://marc.info/?l=linux-kernel&m=152449131114778&w=2
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/mwave/mwavedd.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/char/mwave/mwavedd.c b/drivers/char/mwave/mwavedd.c index b5e3103c1175..e43c876a9223 100644 --- a/drivers/char/mwave/mwavedd.c +++ b/drivers/char/mwave/mwavedd.c @@ -59,6 +59,7 @@ #include <linux/mutex.h> #include <linux/delay.h> #include <linux/serial_8250.h> +#include <linux/nospec.h> #include "smapi.h" #include "mwavedd.h" #include "3780i.h" @@ -289,6 +290,8 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd, ipcnum); return -EINVAL; } + ipcnum = array_index_nospec(ipcnum, + ARRAY_SIZE(pDrvData->IPCs)); PRINTK_3(TRACE_MWAVE, "mwavedd::mwave_ioctl IOCTL_MW_REGISTER_IPC" " ipcnum %x entry usIntCount %x\n", @@ -317,6 +320,8 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd, " Invalid ipcnum %x\n", ipcnum); return -EINVAL; } + ipcnum = array_index_nospec(ipcnum, + ARRAY_SIZE(pDrvData->IPCs)); PRINTK_3(TRACE_MWAVE, "mwavedd::mwave_ioctl IOCTL_MW_GET_IPC" " ipcnum %x, usIntCount %x\n", @@ -383,6 +388,8 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd, ipcnum); return -EINVAL; } + ipcnum = array_index_nospec(ipcnum, + ARRAY_SIZE(pDrvData->IPCs)); mutex_lock(&mwave_mutex); if (pDrvData->IPCs[ipcnum].bIsEnabled == true) { pDrvData->IPCs[ipcnum].bIsEnabled = false; |