| Message ID | c16b025a-a302-8515-2697-f7eca478e939@xilinx.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
Hi Michal, On Tue, Feb 20, 2018 at 11:22 AM, Michal Simek <michal.simek@xilinx.com> wrote: > On 20.2.2018 10:40, Geert Uytterhoeven wrote: >> The cdns_uart_port[] array is indexed using a value derived from the >> "serialN" alias in DT, which may lead to an out-of-bounds access. >> >> Fix this by adding a range check. >> >> Fixes: 1f118c02a1819856 ("serial: xuartps: Fix out-of-bounds access through DT alias") > > I didn't find this sha1 - patch name is this one. Bummer, I totally screwed up my scripting... Fixes: 928e9263492069ee ("tty: xuartps: Initialize ports according to aliases") >> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >> --- >> drivers/tty/serial/xilinx_uartps.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c >> index b9b2bc76bcac606c..abcb4d09a2d866d0 100644 >> --- a/drivers/tty/serial/xilinx_uartps.c >> +++ b/drivers/tty/serial/xilinx_uartps.c >> @@ -1110,7 +1110,7 @@ static struct uart_port *cdns_uart_get_port(int id) >> struct uart_port *port; >> >> /* Try the given port id if failed use default method */ >> - if (cdns_uart_port[id].mapbase != 0) { >> + if (id < CDNS_UART_NR_PORTS && cdns_uart_port[id].mapbase != 0) { >> /* Find the next unused port */ >> for (id = 0; id < CDNS_UART_NR_PORTS; id++) >> if (cdns_uart_port[id].mapbase == 0) >> > > Below should be better fix for this driver. I considered that, too, but... > --- a/drivers/tty/serial/xilinx_uartps.c > +++ b/drivers/tty/serial/xilinx_uartps.c > @@ -1109,6 +1109,9 @@ static struct uart_port *cdns_uart_get_port(int id) > { > struct uart_port *port; > > + if (id >= CDNS_UART_NR_PORTS) > + return NULL; > + > /* Try the given port id if failed use default method */ > if (cdns_uart_port[id].mapbase != 0) { > /* Find the next unused port */ > @@ -1117,9 +1120,6 @@ static struct uart_port *cdns_uart_get_port(int id) > break; > } > > - if (id >= CDNS_UART_NR_PORTS) > - return NULL; > - ... the above check cannot be removed, as it is needed to support the loop above to find an unused port. > port = &cdns_uart_port[id]; > > /* At this point, we've got an empty uart_port struct, > initialize it */ Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On 20.2.2018 11:38, Geert Uytterhoeven wrote: > Hi Michal, > > On Tue, Feb 20, 2018 at 11:22 AM, Michal Simek <michal.simek@xilinx.com> wrote: >> On 20.2.2018 10:40, Geert Uytterhoeven wrote: >>> The cdns_uart_port[] array is indexed using a value derived from the >>> "serialN" alias in DT, which may lead to an out-of-bounds access. >>> >>> Fix this by adding a range check. >>> >>> Fixes: 1f118c02a1819856 ("serial: xuartps: Fix out-of-bounds access through DT alias") >> >> I didn't find this sha1 - patch name is this one. > > Bummer, I totally screwed up my scripting... > > Fixes: 928e9263492069ee ("tty: xuartps: Initialize ports according to aliases") > >>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >>> --- >>> drivers/tty/serial/xilinx_uartps.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c >>> index b9b2bc76bcac606c..abcb4d09a2d866d0 100644 >>> --- a/drivers/tty/serial/xilinx_uartps.c >>> +++ b/drivers/tty/serial/xilinx_uartps.c >>> @@ -1110,7 +1110,7 @@ static struct uart_port *cdns_uart_get_port(int id) >>> struct uart_port *port; >>> >>> /* Try the given port id if failed use default method */ >>> - if (cdns_uart_port[id].mapbase != 0) { >>> + if (id < CDNS_UART_NR_PORTS && cdns_uart_port[id].mapbase != 0) { >>> /* Find the next unused port */ >>> for (id = 0; id < CDNS_UART_NR_PORTS; id++) >>> if (cdns_uart_port[id].mapbase == 0) >>> >> >> Below should be better fix for this driver. > > I considered that, too, but... > >> --- a/drivers/tty/serial/xilinx_uartps.c >> +++ b/drivers/tty/serial/xilinx_uartps.c >> @@ -1109,6 +1109,9 @@ static struct uart_port *cdns_uart_get_port(int id) >> { >> struct uart_port *port; >> >> + if (id >= CDNS_UART_NR_PORTS) >> + return NULL; >> + >> /* Try the given port id if failed use default method */ >> if (cdns_uart_port[id].mapbase != 0) { >> /* Find the next unused port */ >> @@ -1117,9 +1120,6 @@ static struct uart_port *cdns_uart_get_port(int id) >> break; >> } >> >> - if (id >= CDNS_UART_NR_PORTS) >> - return NULL; >> - > > ... the above check cannot be removed, as it is needed to support the loop > above to find an unused port. You are right. I have checked 4 patches I have sent in past which didn't reach mainline (probably because of RFC) Take a look at https://www.spinics.net/lists/linux-serial/msg27106.html I have removed cdns_uart_port array completely there. Thanks, Michal
Hi Michal, On Tue, Feb 20, 2018 at 12:27 PM, Michal Simek <michal.simek@xilinx.com> wrote: > On 20.2.2018 11:38, Geert Uytterhoeven wrote: >> On Tue, Feb 20, 2018 at 11:22 AM, Michal Simek <michal.simek@xilinx.com> wrote: >>> On 20.2.2018 10:40, Geert Uytterhoeven wrote: >>>> The cdns_uart_port[] array is indexed using a value derived from the >>>> "serialN" alias in DT, which may lead to an out-of-bounds access. >>>> >>>> Fix this by adding a range check. > I have checked 4 patches I have sent in past which didn't reach mainline > (probably because of RFC) > Take a look at > https://www.spinics.net/lists/linux-serial/msg27106.html > > I have removed cdns_uart_port array completely there. Nice! I'd love to get rid of fixed arrays in serial... However, IMHO it's still worthwhile to fix the out-of-bounds access first, as that fix can be backported to stable kernels easily. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On 20.2.2018 13:27, Geert Uytterhoeven wrote: > Hi Michal, > > On Tue, Feb 20, 2018 at 12:27 PM, Michal Simek <michal.simek@xilinx.com> wrote: >> On 20.2.2018 11:38, Geert Uytterhoeven wrote: >>> On Tue, Feb 20, 2018 at 11:22 AM, Michal Simek <michal.simek@xilinx.com> wrote: >>>> On 20.2.2018 10:40, Geert Uytterhoeven wrote: >>>>> The cdns_uart_port[] array is indexed using a value derived from the >>>>> "serialN" alias in DT, which may lead to an out-of-bounds access. >>>>> >>>>> Fix this by adding a range check. > >> I have checked 4 patches I have sent in past which didn't reach mainline >> (probably because of RFC) >> Take a look at >> https://www.spinics.net/lists/linux-serial/msg27106.html >> >> I have removed cdns_uart_port array completely there. > > Nice! I'd love to get rid of fixed arrays in serial... > > However, IMHO it's still worthwhile to fix the out-of-bounds access first, > as that fix can be backported to stable kernels easily. I agree with you. Not a problem with your patch and for me it won't be problem to rebase. I would love to get rid of CDNS_UART_NR_PORTS but unfortunately this is passed to core via .nr. Thanks, Michal
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index b9b2bc76bcac..b77c6477ed93 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -1109,6 +1109,9 @@ static struct uart_port *cdns_uart_get_port(int id) { struct uart_port *port; + if (id >= CDNS_UART_NR_PORTS) + return NULL; + /* Try the given port id if failed use default method */ if (cdns_uart_port[id].mapbase != 0) { /* Find the next unused port */ @@ -1117,9 +1120,6 @@ static struct uart_port *cdns_uart_get_port(int id) break; } - if (id >= CDNS_UART_NR_PORTS) - return NULL; - port = &cdns_uart_port[id]; /* At this point, we've got an empty uart_port struct,