The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200227183748.GA31018@embeddedor
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
- Use overflow helpers in 2-factor allocators (Kees, Rasmus)
- Introduce overflow test module (Rasmus, Kees)
- Introduce saturating size helper functions (Matthew, Kees)
- Treewide use of struct_size() for allocators (Kees)
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Merge tag 'overflow-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull overflow updates from Kees Cook:
"This adds the new overflow checking helpers and adds them to the
2-factor argument allocators. And this adds the saturating size
helpers and does a treewide replacement for the struct_size() usage.
Additionally this adds the overflow testing modules to make sure
everything works.
I'm still working on the treewide replacements for allocators with
"simple" multiplied arguments:
*alloc(a * b, ...) -> *alloc_array(a, b, ...)
and
*zalloc(a * b, ...) -> *calloc(a, b, ...)
as well as the more complex cases, but that's separable from this
portion of the series. I expect to have the rest sent before -rc1
closes; there are a lot of messy cases to clean up.
Summary:
- Introduce arithmetic overflow test helper functions (Rasmus)
- Use overflow helpers in 2-factor allocators (Kees, Rasmus)
- Introduce overflow test module (Rasmus, Kees)
- Introduce saturating size helper functions (Matthew, Kees)
- Treewide use of struct_size() for allocators (Kees)"
* tag 'overflow-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
treewide: Use struct_size() for devm_kmalloc() and friends
treewide: Use struct_size() for vmalloc()-family
treewide: Use struct_size() for kmalloc()-family
device: Use overflow helpers for devm_kmalloc()
mm: Use overflow helpers in kvmalloc()
mm: Use overflow helpers in kmalloc_array*()
test_overflow: Add memory allocation overflow tests
overflow.h: Add allocation size calculation helpers
test_overflow: Report test failures
test_overflow: macrofy some more, do more tests for free
lib: add runtime test of check_*_overflow functions
compiler.h: enable builtin overflow checkers and add fallback code
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL);
This patch makes the changes for kmalloc()-family (and kvmalloc()-family)
uses. It was done via automatic conversion with manual review for the
"CHECKME" non-standard cases noted below, using the following Coccinelle
script:
// pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len *
// sizeof *pkey_cache->table, GFP_KERNEL);
@@
identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc";
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@
- alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP)
+ alloc(struct_size(VAR, ELEMENT, COUNT), GFP)
// mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL);
@@
identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc";
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@
- alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP)
+ alloc(struct_size(VAR, ELEMENT, COUNT), GFP)
// Same pattern, but can't trivially locate the trailing element name,
// or variable name.
@@
identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc";
expression GFP;
expression SOMETHING, COUNT, ELEMENT;
@@
- alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP)
+ alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP)
Signed-off-by: Kees Cook <keescook@chromium.org>
The generic DMA API uses dev->dma_mask to check the DMA addressable
memory bitmask, and warns if no mask is set or even allocated.
Set z->dev.dma_coherent_mask on Zorro bus scan, and make z->dev.dma_mask
to point to z->dev.dma_coherent_mask so device drivers that need DMA have
everything set up to avoid warnings from dma_alloc_coherent(). Drivers can
still use dma_set_mask_and_coherent() to explicitly set their DMA bit mask.
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
[geert: Handle Zorro II with 24-bit address space]
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Instead of creating attributes one by one, define attribute_group array
and attach it to bus->dev_groups, so that all needed attributes are created
automatically when a new device is registered on the bus.
Also switch to using standard DEVICE_ATTR_RO() macros.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix member definitions for non-native userspace handling:
- All multi-byte values are big-endian, hence use __be*,
- All pointers are 32-bit pointers under AmigaOS, but unused (except for
cd_BoardAddr) under Linux, hence use __be32.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Filling in dev_name of the Zorro bus type and dev.id of each device allows
the driver core to enumerate devices, so we don't have to do that
ourselves.
This changes the names of devices in sysfs from "%02x" to "zorro%u".
Note that filling in dev.id is also needed to support MFD Zorro devices.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Currently the array of Zorro devices is allocated statically, wasting
up to 4.5 KiB when running an Amiga or multi-platform kernel on a machine
with no or a handful of Zorro expansion cards. Convert it to conditional
dynamic memory allocation to fix this.
amiga_parse_bootinfo() still needs to store some information about the
detected Zorro devices, at a time even the bootmem allocator is not yet
available. This is now handled using a much smaller array (typically less
than 0.5 KiB), which is __initdata and thus freed later.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
As the Amiga Zorro II address space is limited to 8.5 MiB and Zorro
devices can contain only one BAR, several Amiga Zorro II expansion
boards (mainly graphics cards) contain multiple Zorro devices: a small
one for the control registers and one (or more) for the graphics memory.
The conversion of cirrusfb to the new driver framework introduced a
regression: the driver contains a zorro_driver for the first Zorro
device, and uses the (old) zorro_find_device() call to find the second
Zorro device.
However, as the Zorro core calls device_register() as soon as a Zorro
device is identified, it may not have identified the second Zorro device
belonging to the same physical Zorro expansion card. Hence cirrusfb
could no longer find the second part of the Picasso II graphics card,
causing a NULL pointer dereference.
Defer the registration of Zorro devices with the driver framework until
all Zorro devices have been identified to fix this.
Note that the alternative solution (modifying cirrusfb to register a
zorro_driver for all Zorro devices belonging to a graphics card, instead
of only for the first one, and adding a synchronization mechanism to
defer initialization until all have been found), is not an option, as on
some cards one device may be optional (e.g. the second bank of 2 MiB of
graphics memory on the Picasso IV in Zorro II mode).
Reported-by: Ingo Jürgensmann <ij@2011.bluespice.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If device_register() fails then call put_device().
See comment to device_register.
Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
warning: ignoring return value of 'device_register', declared with attribute
warn_unused_result
warning: ignoring return value of 'device_create_file', declared with
attribute warn_unused_result
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
This patch removes CVS keywords that weren't updated for a long time
from comments.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kill resource_size_t warnings by casting resource_size_t to unsigned long when
formatting Zorro bus resources, as they are always 32-bit.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I recently picked up my older work to remove unnecessary #includes of
sched.h, starting from a patch by Dave Jones to not include sched.h
from module.h. This reduces the number of indirect includes of sched.h
by ~300. Another ~400 pointless direct includes can be removed after
this disentangling (patch to follow later).
However, quite a few indirect includes need to be fixed up for this.
In order to feed the patches through -mm with as little disturbance as
possible, I've split out the fixes I accumulated up to now (complete for
i386 and x86_64, more archs to follow later) and post them before the real
patch. This way this large part of the patch is kept simple with only
adding #includes, and all hunks are independent of each other. So if any
hunk rejects or gets in the way of other patches, just drop it. My scripts
will pick it up again in the next round.
Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Gustavo A. R. Silva