linux-toradex.git/include/linux/overflow.h, branch v6.0-rc7

tracing: Define the is_signed_type() macro once

2022-08-29T20:29:40+00:00

There are two definitions of the is_signed_type() macro: one in
 and a second definition in .

As suggested by Linus, move the definition of the is_signed_type() macro
into the  header file.  Change the definition of the
is_signed_type() macro to make sure that it does not trigger any sparse
warnings with future versions of sparse for bitwise types.

Link: https://lore.kernel.org/all/CAHk-=whjH6p+qzwUdx5SOVVHjS3WvzJQr6mDUwhEyTf6pJWzaQ@mail.gmail.com/
Link: https://lore.kernel.org/all/CAHk-=wjQGnVfb4jehFR0XyZikdQvCZouE96xR_nnf5kqaM5qqQ@mail.gmail.com/
Cc: Rasmus Villemoes 
Cc: Steven Rostedt 
Acked-by: Kees Cook 
Signed-off-by: Bart Van Assche 
Signed-off-by: Linus Torvalds

overflow: Provide constant expression struct_size

2022-02-16T22:30:37+00:00

There have been cases where struct_size() (or flex_array_size()) needs
to be calculated for an initializer, which requires it be a constant
expression. This is possible when the "count" argument is a constant
expression, so provide this ability for the helpers.

Cc: Gustavo A. R. Silva 
Cc: Nathan Chancellor 
Cc: Nick Desaulniers 
Cc: Rasmus Villemoes 
Signed-off-by: Kees Cook 
Reviewed-by: Gustavo A. R. Silva 
Tested-by: Gustavo A. R. Silva 
Link: https://lore.kernel.org/lkml/20220210010407.GA701603@embeddedor

overflow: Implement size_t saturating arithmetic helpers

2022-02-16T22:29:48+00:00

In order to perform more open-coded replacements of common allocation
size arithmetic, the kernel needs saturating (SIZE_MAX) helpers for
multiplication, addition, and subtraction. For example, it is common in
allocators, especially on realloc, to add to an existing size:

    p = krealloc(map->patch,
                 sizeof(struct reg_sequence) * (map->patch_regs + num_regs),
                 GFP_KERNEL);

There is no existing saturating replacement for this calculation, and
just leaving the addition open coded inside array_size() could
potentially overflow as well. For example, an overflow in an expression
for a size_t argument might wrap to zero:

    array_size(anything, something_at_size_max + 1) == 0

Introduce size_mul(), size_add(), and size_sub() helpers that
implicitly promote arguments to size_t and saturated calculations for
use in allocations. With these helpers it is also possible to redefine
array_size(), array3_size(), flex_array_size(), and struct_size() in
terms of the new helpers.

As with the check_*_overflow() helpers, the new helpers use __must_check,
though what is really desired is a way to make sure that assignment is
only to a size_t lvalue. Without this, it's still possible to introduce
overflow/underflow via type conversion (i.e. from size_t to int).
Enforcing this will currently need to be left to static analysis or
future use of -Wconversion.

Additionally update the overflow unit tests to force runtime evaluation
for the pathological cases.

Cc: Rasmus Villemoes 
Cc: Gustavo A. R. Silva 
Cc: Nathan Chancellor 
Cc: Jason Gunthorpe 
Cc: Nick Desaulniers 
Cc: Leon Romanovsky 
Cc: Keith Busch 
Cc: Len Baker 
Signed-off-by: Kees Cook

compiler.h: drop fallback overflow checkers

2021-09-13T17:18:28+00:00

Once upgrading the minimum supported version of GCC to 5.1, we can drop
the fallback code for !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW.

This is effectively a revert of commit f0907827a8a9 ("compiler.h: enable
builtin overflow checkers and add fallback code")

Link: https://github.com/ClangBuiltLinux/linux/issues/1438#issuecomment-916745801
Suggested-by: Rasmus Villemoes 
Signed-off-by: Nick Desaulniers 
Acked-by: Kees Cook 
Reviewed-by: Nathan Chancellor 
Signed-off-by: Linus Torvalds

overflow: Correct check_shl_overflow() comment

2021-04-01T21:07:41+00:00

A 'false' return means the value was safely set, so the comment should
say 'true' for when it is not considered safe.

Cc: Jason Gunthorpe 
Signed-off-by: Keith Busch 
Signed-off-by: Kees Cook 
Fixes: 0c66847793d1 ("overflow.h: Add arithmetic shift helper")
Link: https://lore.kernel.org/r/20210401160629.1941787-1-kbusch@kernel.org

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma

2020-10-17T18:18:18+00:00

Pull rdma updates from Jason Gunthorpe:
 "A usual cycle for RDMA with a typical mix of driver and core subsystem
  updates:

   - Driver minor changes and bug fixes for mlx5, efa, rxe, vmw_pvrdma,
     hns, usnic, qib, qedr, cxgb4, hns, bnxt_re

   - Various rtrs fixes and updates

   - Bug fix for mlx4 CM emulation for virtualization scenarios where
     MRA wasn't working right

   - Use tracepoints instead of pr_debug in the CM code

   - Scrub the locking in ucma and cma to close more syzkaller bugs

   - Use tasklet_setup in the subsystem

   - Revert the idea that 'destroy' operations are not allowed to fail
     at the driver level. This proved unworkable from a HW perspective.

   - Revise how the umem API works so drivers make fewer mistakes using
     it

   - XRC support for qedr

   - Convert uverbs objects RWQ and MW to new the allocation scheme

   - Large queue entry sizes for hns

   - Use hmm_range_fault() for mlx5 On Demand Paging

   - uverbs APIs to inspect the GID table instead of sysfs

   - Move some of the RDMA code for building large page SGLs into
     lib/scatterlist"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (191 commits)
  RDMA/ucma: Fix use after free in destroy id flow
  RDMA/rxe: Handle skb_clone() failure in rxe_recv.c
  RDMA/rxe: Move the definitions for rxe_av.network_type to uAPI
  RDMA: Explicitly pass in the dma_device to ib_register_device
  lib/scatterlist: Do not limit max_segment to PAGE_ALIGNED values
  IB/mlx4: Convert rej_tmout radix-tree to XArray
  RDMA/rxe: Fix bug rejecting all multicast packets
  RDMA/rxe: Fix skb lifetime in rxe_rcv_mcast_pkt()
  RDMA/rxe: Remove duplicate entries in struct rxe_mr
  IB/hfi,rdmavt,qib,opa_vnic: Update MAINTAINERS
  IB/rdmavt: Fix sizeof mismatch
  MAINTAINERS: CISCO VIC LOW LATENCY NIC DRIVER
  RDMA/bnxt_re: Fix sizeof mismatch for allocation of pbl_tbl.
  RDMA/bnxt_re: Use rdma_umem_for_each_dma_block()
  RDMA/umem: Move to allocate SG table from pages
  lib/scatterlist: Add support in dynamic allocation of SG table from pages
  tools/testing/scatterlist: Show errors in human readable form
  tools/testing/scatterlist: Rejuvenate bit-rotten test
  RDMA/ipoib: Set rtnl_link_ops for ipoib interfaces
  RDMA/uverbs: Expose the new GID query API to user space
  ...

overflow: Add __must_check attribute to check_*() helpers

2020-10-12T22:19:07+00:00

Since the destination variable of the check_*_overflow() helpers will
contain a wrapped value on failure, it would be best to make sure callers
really did check the return result of the helper. Adjust the macros to use
a bool-wrapping static inline that is marked with __must_check. This means
the macros can continue to have their type-agnostic behavior while gaining
the function attribute (that cannot be applied directly to macros).

Suggested-by: Rasmus Villemoes 
Link: https://lore.kernel.org/lkml/202008151007.EF679DF@keescook/
Signed-off-by: Kees Cook

overflow: Include header file with SIZE_MAX declaration

2020-10-02T00:20:11+00:00

The various array_size functions use SIZE_MAX define, but missed limits.h
causes to failure to compile code that needs overflow.h.

 In file included from drivers/infiniband/core/uverbs_std_types_device.c:6:
 ./include/linux/overflow.h: In function 'array_size':
 ./include/linux/overflow.h:258:10: error: 'SIZE_MAX' undeclared (first use in this function)
   258 |   return SIZE_MAX;
       |          ^~~~~~~~

Fixes: 610b15c50e86 ("overflow.h: Add allocation size calculation helpers")
Link: https://lore.kernel.org/r/20200913102928.134985-1-leon@kernel.org
Signed-off-by: Leon Romanovsky 
Signed-off-by: Jason Gunthorpe

overflow.h: Add flex_array_size() helper

2020-06-17T03:45:08+00:00

Add flex_array_size() helper for the calculation of the size, in bytes,
of a flexible array member contained within an enclosing structure.

Example of usage:

struct something {
	size_t count;
	struct foo items[];
};

struct something *instance;

instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
instance->count = count;
memcpy(instance->items, src, flex_array_size(instance, items, instance->count));

The helper returns SIZE_MAX on overflow instead of wrapping around.

Additionally replaces parameter "n" with "count" in struct_size() helper
for greater clarity and unification.

Signed-off-by: Gustavo A. R. Silva 
Link: https://lore.kernel.org/r/20200609012233.GA3371@embeddedor
Signed-off-by: Kees Cook

Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-05-16T17:29:00+00:00

Pull core fixes from Ingo Molnar:
 "A handful of objtool updates, plus a documentation addition for
  __ab_c_size()"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix whitelist documentation typo
  objtool: Fix function fallthrough detection
  objtool: Don't use ignore flag for fake jumps
  overflow.h: Add comment documenting __ab_c_size()