5.4-stable review patch. If anyone has any objections, please let me know.
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From: Alex Williamson alex.williamson@redhat.com
commit ce9ff21ea89d191e477a02ad7eabf4f996b80a69 upstream.
count and offset are passed from user space and not checked, only offset is capped to 40 bits, which can be used to read/write out of bounds of the device.
Fixes: 6e3f26456009 (“vfio/platform: read and write support for the device fd”) Cc: stable@vger.kernel.org Reported-by: Mostafa Saleh smostafa@google.com Reviewed-by: Eric Auger eric.auger@redhat.com Reviewed-by: Mostafa Saleh smostafa@google.com Tested-by: Mostafa Saleh smostafa@google.com Signed-off-by: Alex Williamson alex.williamson@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vfio/platform/vfio_platform_common.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/drivers/vfio/platform/vfio_platform_common.c +++ b/drivers/vfio/platform/vfio_platform_common.c @@ -410,6 +410,11 @@ static ssize_t vfio_platform_read_mmio(s
count = min_t(size_t, count, reg->size - off);
+ if (off >= reg->size) + return -EINVAL; + + count = min_t(size_t, count, reg->size - off); + if (!reg->ioaddr) { reg->ioaddr = ioremap_nocache(reg->addr, reg->size); @@ -489,6 +494,11 @@ static ssize_t vfio_platform_write_mmio(
if (off >= reg->size) return -EINVAL; + + count = min_t(size_t, count, reg->size - off); + + if (off >= reg->size) + return -EINVAL;
count = min_t(size_t, count, reg->size - off);