2018-07-27 13:41:10

by Anton Vasilyev

Subject: [PATCH] tty: rocket: Fix possible buffer overwrite on register_PCI

If number of isa and pci boards exceed NUM_BOARDS on the path
rp_init()->init_PCI()->register_PCI() then buffer overwrite occurs
in register_PCI() on assign rcktpt_io_addr[i].

The patch adds check on upper bound for index of registered
board in register_PCI.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <[email protected]>
---
drivers/tty/rocket.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
index bdd17d2aaafd..b121d8f8f3d7 100644
--- a/drivers/tty/rocket.c
+++ b/drivers/tty/rocket.c
@@ -1881,7 +1881,7 @@ static __init int register_PCI(int i, struct pci_dev *dev)
ByteIO_t UPCIRingInd = 0;

if (!dev || !pci_match_id(rocket_pci_ids, dev) ||
- pci_enable_device(dev))
+ pci_enable_device(dev) || i >= NUM_BOARDS)
return 0;

rcktpt_io_addr[i] = pci_resource_start(dev, 0);
--
2.18.0

2018-08-02 14:03:56

by Alan Cox

Subject: Re: [PATCH] tty: rocket: Fix possible buffer overwrite on register_PCI

On Fri, 27 Jul 2018 16:39:31 +0300
Anton Vasilyev <[email protected]> wrote:

> If number of isa and pci boards exceed NUM_BOARDS on the path
> rp_init()->init_PCI()->register_PCI() then buffer overwrite occurs
> in register_PCI() on assign rcktpt_io_addr[i].
>
> The patch adds check on upper bound for index of registered
> board in register_PCI.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Anton Vasilyev <[email protected]>
> ---
> drivers/tty/rocket.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
> index bdd17d2aaafd..b121d8f8f3d7 100644
> --- a/drivers/tty/rocket.c
> +++ b/drivers/tty/rocket.c
> @@ -1881,7 +1881,7 @@ static __init int register_PCI(int i, struct pci_dev *dev)
> ByteIO_t UPCIRingInd = 0;
>
> if (!dev || !pci_match_id(rocket_pci_ids, dev) ||
> - pci_enable_device(dev))
> + pci_enable_device(dev) || i >= NUM_BOARDS)
> return 0;
>
> rcktpt_io_addr[i] = pci_resource_start(dev, 0);

This is a real fix but you want to check i >= NUM_BOARDS before you
enable the device

Alan

2018-08-06 16:35:41

by Anton Vasilyev

Subject: [PATCH v2] tty: rocket: Fix possible buffer overwrite on register_PCI

If number of isa and pci boards exceed NUM_BOARDS on the path
rp_init()->init_PCI()->register_PCI() then buffer overwrite occurs
in register_PCI() on assign rcktpt_io_addr[i].

The patch adds check on upper bound for index of registered
board in register_PCI.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <[email protected]>
---
v2: do not enable device which will not be managed by driver.
Based on Alan's comment.

NOTE: I can't find if there is a call of pci_disable_device(),
corresponding to pci_enable_device() from register_PCI().
---
drivers/tty/rocket.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
index bdd17d2aaafd..f2238dc40426 100644
--- a/drivers/tty/rocket.c
+++ b/drivers/tty/rocket.c
@@ -1881,7 +1881,7 @@ static __init int register_PCI(int i, struct pci_dev *dev)
ByteIO_t UPCIRingInd = 0;

if (!dev || !pci_match_id(rocket_pci_ids, dev) ||
- pci_enable_device(dev))
+ i >= NUM_BOARDS || pci_enable_device(dev))
return 0;

rcktpt_io_addr[i] = pci_resource_start(dev, 0);
--
2.18.0

2018-09-18 13:40:10

by Greg Kroah-Hartman

Subject: Re: [PATCH v2] tty: rocket: Fix possible buffer overwrite on register_PCI

On Mon, Aug 06, 2018 at 05:10:57PM +0300, Anton Vasilyev wrote:
> If number of isa and pci boards exceed NUM_BOARDS on the path
> rp_init()->init_PCI()->register_PCI() then buffer overwrite occurs
> in register_PCI() on assign rcktpt_io_addr[i].
>
> The patch adds check on upper bound for index of registered
> board in register_PCI.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Anton Vasilyev <[email protected]>
> ---
> v2: do not enable device which will not be managed by driver.
> Based on Alan's comment.

This patch doesn't apply to my tree at all :(

Can you rebase and resend?

thanks,

greg k-h