| Message ID | 20201007114615.19966-1-colin.king@canonical.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | PCI: fix a potential uninitentional integer overflow issue | expand |
On Wed, Oct 07, 2020 at 12:46:15PM +0100, Colin King wrote: > From: Colin Ian King <colin.king@canonical.com> > > The shift of 1 by align_order is evaluated using 32 bit arithmetic > and the result is assigned to a resource_size_t type variable that > is a 64 bit unsigned integer on 64 bit platforms. Fix an overflow > before widening issue by using the BIT_ULL macro to perform the > shift. > > Addresses-Coverity: ("Uninitentional integer overflow") > Fixes: 07d8d7e57c28 ("PCI: Make specifying PCI devices in kernel parameters reusable") > Signed-off-by: Colin Ian King <colin.king@canonical.com> > --- > drivers/pci/pci.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 6d4d5a2f923d..1a5844d7af35 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -6209,7 +6209,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, > if (align_order == -1) > align = PAGE_SIZE; > else > - align = 1 << align_order; > + align = BIT_ULL(align_order); "align_order" comes from sscanf() so Smatch thinks it's not trusted. Anything above 63 is undefined behavior. There should be a bounds check on this but I don't know what the valid values of "align" are. regards, dan carpenter
On Wed, Oct 07, 2020 at 03:33:45PM +0300, Dan Carpenter wrote: > On Wed, Oct 07, 2020 at 12:46:15PM +0100, Colin King wrote: > > From: Colin Ian King <colin.king@canonical.com> > > > > The shift of 1 by align_order is evaluated using 32 bit arithmetic > > and the result is assigned to a resource_size_t type variable that > > is a 64 bit unsigned integer on 64 bit platforms. Fix an overflow > > before widening issue by using the BIT_ULL macro to perform the > > shift. > > > > Addresses-Coverity: ("Uninitentional integer overflow") s/Uninitentional/Unintentional/ Also in subject (please also capitalize subject) Doesn't Coverity also assign an ID number for this specific issue? Can you include that as well, e.g., Addresses-Coverity-ID: 1226899 ("Unintentional integer overflow") > > Fixes: 07d8d7e57c28 ("PCI: Make specifying PCI devices in kernel parameters reusable") > > Signed-off-by: Colin Ian King <colin.king@canonical.com> > > --- > > drivers/pci/pci.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index 6d4d5a2f923d..1a5844d7af35 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -6209,7 +6209,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, > > if (align_order == -1) > > align = PAGE_SIZE; > > else > > - align = 1 << align_order; > > + align = BIT_ULL(align_order); > > "align_order" comes from sscanf() so Smatch thinks it's not trusted. > Anything above 63 is undefined behavior. There should be a bounds check > on this but I don't know what the valid values of "align" are. The spec doesn't explicitly say what the size limit for 64-bit BARs is, but it does say 32-bit BARs can support up to 2GB (2^31). So I infer that 2^63 would be the limit for 64-bit BARs. What about something like the following? To me, BIT_ULL doesn't seem like an advantage over "1ULL << ", but maybe there's a reason to use it. diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 8b9bea8ba751..6e17d0a6828a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6197,19 +6197,21 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, while (*p) { count = 0; if (sscanf(p, "%d%n", &align_order, &count) == 1 && - p[count] == '@') { + p[count] == '@') { p += count + 1; + if (align_order > 63) { + pr_err("PCI: Invalid requested alignment (order %d)\n", + align_order); + align_order = PAGE_SHIFT; + } } else { - align_order = -1; + align_order = PAGE_SHIFT; } ret = pci_dev_str_match(dev, p, &p); if (ret == 1) { *resize = true; - if (align_order == -1) - align = PAGE_SIZE; - else - align = 1 << align_order; + align = 1ULL << align_order; break; } else if (ret < 0) { pr_err("PCI: Can't parse resource_alignment parameter: %s\n",
On Thu, Nov 05, 2020 at 04:24:30PM -0600, Bjorn Helgaas wrote: > On Wed, Oct 07, 2020 at 03:33:45PM +0300, Dan Carpenter wrote: > > On Wed, Oct 07, 2020 at 12:46:15PM +0100, Colin King wrote: > > > From: Colin Ian King <colin.king@canonical.com> > > > > > > The shift of 1 by align_order is evaluated using 32 bit arithmetic > > > and the result is assigned to a resource_size_t type variable that > > > is a 64 bit unsigned integer on 64 bit platforms. Fix an overflow > > > before widening issue by using the BIT_ULL macro to perform the > > > shift. > > > > > > Addresses-Coverity: ("Uninitentional integer overflow") > > s/Uninitentional/Unintentional/ > Also in subject (please also capitalize subject) > > Doesn't Coverity also assign an ID number for this specific issue? > Can you include that as well, e.g., > > Addresses-Coverity-ID: 1226899 ("Unintentional integer overflow") > > > > Fixes: 07d8d7e57c28 ("PCI: Make specifying PCI devices in kernel parameters reusable") > > > Signed-off-by: Colin Ian King <colin.king@canonical.com> > > > --- > > > drivers/pci/pci.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > > index 6d4d5a2f923d..1a5844d7af35 100644 > > > --- a/drivers/pci/pci.c > > > +++ b/drivers/pci/pci.c > > > @@ -6209,7 +6209,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, > > > if (align_order == -1) > > > align = PAGE_SIZE; > > > else > > > - align = 1 << align_order; > > > + align = BIT_ULL(align_order); > > > > "align_order" comes from sscanf() so Smatch thinks it's not trusted. > > Anything above 63 is undefined behavior. There should be a bounds check > > on this but I don't know what the valid values of "align" are. > > The spec doesn't explicitly say what the size limit for 64-bit BARs > is, but it does say 32-bit BARs can support up to 2GB (2^31). So I > infer that 2^63 would be the limit for 64-bit BARs. > > What about something like the following? To me, BIT_ULL doesn't seem > like an advantage over "1ULL << ", but maybe there's a reason to use > it. The advantage of BIT_ULL() is that checkpatch and I think Coccinelle will suggest using it. It's only recently where a few people have complained (actually you're probably the second person) that BIT() is sort of a weird thing to use for size variables. regards, dan carpenter
On Fri, Nov 06, 2020 at 11:04:19AM +0300, Dan Carpenter wrote: > On Thu, Nov 05, 2020 at 04:24:30PM -0600, Bjorn Helgaas wrote: > > On Wed, Oct 07, 2020 at 03:33:45PM +0300, Dan Carpenter wrote: > > > On Wed, Oct 07, 2020 at 12:46:15PM +0100, Colin King wrote: > > > > From: Colin Ian King <colin.king@canonical.com> > > > > > > > > The shift of 1 by align_order is evaluated using 32 bit arithmetic > > > > and the result is assigned to a resource_size_t type variable that > > > > is a 64 bit unsigned integer on 64 bit platforms. Fix an overflow > > > > before widening issue by using the BIT_ULL macro to perform the > > > > shift. > > > > > > > > Addresses-Coverity: ("Uninitentional integer overflow") > > > > s/Uninitentional/Unintentional/ > > Also in subject (please also capitalize subject) > > > > Doesn't Coverity also assign an ID number for this specific issue? > > Can you include that as well, e.g., > > > > Addresses-Coverity-ID: 1226899 ("Unintentional integer overflow") > > > > > > Fixes: 07d8d7e57c28 ("PCI: Make specifying PCI devices in kernel parameters reusable") > > > > Signed-off-by: Colin Ian King <colin.king@canonical.com> > > > > --- > > > > drivers/pci/pci.c | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > > > index 6d4d5a2f923d..1a5844d7af35 100644 > > > > --- a/drivers/pci/pci.c > > > > +++ b/drivers/pci/pci.c > > > > @@ -6209,7 +6209,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, > > > > if (align_order == -1) > > > > align = PAGE_SIZE; > > > > else > > > > - align = 1 << align_order; > > > > + align = BIT_ULL(align_order); > > > > > > "align_order" comes from sscanf() so Smatch thinks it's not trusted. > > > Anything above 63 is undefined behavior. There should be a bounds check > > > on this but I don't know what the valid values of "align" are. > > > > The spec doesn't explicitly say what the size limit for 64-bit BARs > > is, but it does say 32-bit BARs can support up to 2GB (2^31). So I > > infer that 2^63 would be the limit for 64-bit BARs. > > > > What about something like the following? To me, BIT_ULL doesn't seem > > like an advantage over "1ULL << ", but maybe there's a reason to use > > it. > > The advantage of BIT_ULL() is that checkpatch and I think Coccinelle > will suggest using it. It's only recently where a few people have > complained (actually you're probably the second person) that BIT() is > sort of a weird thing to use for size variables. If that's the only reason, I definitely prefer "1ULL << align_order". BIT_ULL is just a pointless abstraction in this case.
On 10/11/2020 20:54, Bjorn Helgaas wrote: > On Fri, Nov 06, 2020 at 11:04:19AM +0300, Dan Carpenter wrote: >> On Thu, Nov 05, 2020 at 04:24:30PM -0600, Bjorn Helgaas wrote: >>> On Wed, Oct 07, 2020 at 03:33:45PM +0300, Dan Carpenter wrote: >>>> On Wed, Oct 07, 2020 at 12:46:15PM +0100, Colin King wrote: >>>>> From: Colin Ian King <colin.king@canonical.com> >>>>> >>>>> The shift of 1 by align_order is evaluated using 32 bit arithmetic >>>>> and the result is assigned to a resource_size_t type variable that >>>>> is a 64 bit unsigned integer on 64 bit platforms. Fix an overflow >>>>> before widening issue by using the BIT_ULL macro to perform the >>>>> shift. >>>>> >>>>> Addresses-Coverity: ("Uninitentional integer overflow") >>> >>> s/Uninitentional/Unintentional/ >>> Also in subject (please also capitalize subject) OK >>> >>> Doesn't Coverity also assign an ID number for this specific issue? >>> Can you include that as well, e.g., I'm running this from an internal coverity scan, so the ID is not public. >>> >>> Addresses-Coverity-ID: 1226899 ("Unintentional integer overflow") >>> >>>>> Fixes: 07d8d7e57c28 ("PCI: Make specifying PCI devices in kernel parameters reusable") >>>>> Signed-off-by: Colin Ian King <colin.king@canonical.com> >>>>> --- >>>>> drivers/pci/pci.c | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >>>>> index 6d4d5a2f923d..1a5844d7af35 100644 >>>>> --- a/drivers/pci/pci.c >>>>> +++ b/drivers/pci/pci.c >>>>> @@ -6209,7 +6209,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, >>>>> if (align_order == -1) >>>>> align = PAGE_SIZE; >>>>> else >>>>> - align = 1 << align_order; >>>>> + align = BIT_ULL(align_order); >>>> >>>> "align_order" comes from sscanf() so Smatch thinks it's not trusted. >>>> Anything above 63 is undefined behavior. There should be a bounds check >>>> on this but I don't know what the valid values of "align" are. >>> >>> The spec doesn't explicitly say what the size limit for 64-bit BARs >>> is, but it does say 32-bit BARs can support up to 2GB (2^31). So I >>> infer that 2^63 would be the limit for 64-bit BARs. >>> >>> What about something like the following? To me, BIT_ULL doesn't seem >>> like an advantage over "1ULL << ", but maybe there's a reason to use >>> it. >> >> The advantage of BIT_ULL() is that checkpatch and I think Coccinelle >> will suggest using it. It's only recently where a few people have >> complained (actually you're probably the second person) that BIT() is >> sort of a weird thing to use for size variables. > > If that's the only reason, I definitely prefer "1ULL << align_order". > > BIT_ULL is just a pointless abstraction in this case. > OK. V2 Arriving later today Colin
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 6d4d5a2f923d..1a5844d7af35 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6209,7 +6209,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, if (align_order == -1) align = PAGE_SIZE; else - align = 1 << align_order; + align = BIT_ULL(align_order); break; } else if (ret < 0) { pr_err("PCI: Can't parse resource_alignment parameter: %s\n",