kernel/linux.git/drivers/misc/lkdtm/refcount.c, branch v6.12.80

refcount: Report UAF for refcount_sub_and_test(0) when counter==0

2024-08-05T21:34:23+00:00

When a reference counter is at zero and refcount_sub_and_test() is invoked to subtract zero, the function accepts this request without any warning and returns true. This behavior does not seem ideal because the counter being already at zero indicates a use-after-free. Furthermore, returning true by refcount_sub_and_test() in this case potentially results in a double-free done by its caller. Modify the underlying function __refcount_sub_and_test() to warn about this case as a use-after-free and have it return false to avoid the potential double-free. Signed-off-by: Petr Pavlu Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20240717130023.5675-1-petr.pavlu@suse.com Signed-off-by: Kees Cook

lkdtm: Move crashtype definitions into each category

2022-04-12T23:16:48+00:00

It's long been annoying that to add a new LKDTM test one had to update lkdtm.h and core.c to get it "registered". Switch to a per-category list and update the crashtype walking code in core.c to handle it. This also means that all the lkdtm_* tests themselves can be static now. Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Signed-off-by: Kees Cook

lkdtm: Remove references to CONFIG_REFCOUNT_FULL

2019-11-25T08:15:46+00:00

CONFIG_REFCOUNT_FULL no longer exists, so remove all references to it. Signed-off-by: Will Deacon Reviewed-by: Ard Biesheuvel Acked-by: Kees Cook Tested-by: Hanjun Guo Cc: Ard Biesheuvel Cc: Elena Reshetova Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20191121115902.2551-11-will@kernel.org Signed-off-by: Ingo Molnar

locking/refcount: Define constants for saturation and max refcount values

2019-11-25T08:14:13+00:00

The REFCOUNT_FULL implementation uses a different saturation point than the x86 implementation, which means that the shared refcount code in lib/refcount.c (e.g. refcount_dec_not_one()) needs to be aware of the difference. Rather than duplicate the definitions from the lkdtm driver, instead move them into and update all references accordingly. Signed-off-by: Will Deacon Reviewed-by: Ard Biesheuvel Reviewed-by: Kees Cook Tested-by: Hanjun Guo Cc: Ard Biesheuvel Cc: Elena Reshetova Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20191121115902.2551-2-will@kernel.org Signed-off-by: Ingo Molnar

lkdtm: Add missing SPDX-License-Identifier line

2018-03-07T03:18:55+00:00

The refcount.c file missed the mass-addition of the SPDX lines. Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman

lkdtm: Relocate code to subdirectory

2018-03-07T03:18:55+00:00

The LKDTM modules keep expanding, and it's getting weird to have each file get a prefix. Instead, move to a subdirectory for cleaner handling. Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman