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author | Joanne Koong <joannelkoong@gmail.com> | 2022-05-23 14:07:07 -0700 |
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committer | Andrii Nakryiko <andrii@kernel.org> | 2022-05-23 14:30:17 -0700 |
commit | 97e03f521050c092919591e668107b3d69c5f426 (patch) | |
tree | d5d2a2dcb2b348c932af968dc9328bb0c75bb95c /include/uapi/linux/matroxfb.h | |
parent | 1ec5ee8c8a5a65ea377f8bea64bf4d5b743f6f79 (diff) | |
download | linux-97e03f521050c092919591e668107b3d69c5f426.tar.gz linux-97e03f521050c092919591e668107b3d69c5f426.tar.bz2 linux-97e03f521050c092919591e668107b3d69c5f426.zip |
bpf: Add verifier support for dynptrs
This patch adds the bulk of the verifier work for supporting dynamic
pointers (dynptrs) in bpf.
A bpf_dynptr is opaque to the bpf program. It is a 16-byte structure
defined internally as:
struct bpf_dynptr_kern {
void *data;
u32 size;
u32 offset;
} __aligned(8);
The upper 8 bits of *size* is reserved (it contains extra metadata about
read-only status and dynptr type). Consequently, a dynptr only supports
memory less than 16 MB.
There are different types of dynptrs (eg malloc, ringbuf, ...). In this
patchset, the most basic one, dynptrs to a bpf program's local memory,
is added. For now only local memory that is of reg type PTR_TO_MAP_VALUE
is supported.
In the verifier, dynptr state information will be tracked in stack
slots. When the program passes in an uninitialized dynptr
(ARG_PTR_TO_DYNPTR | MEM_UNINIT), the stack slots corresponding
to the frame pointer where the dynptr resides at are marked
STACK_DYNPTR. For helper functions that take in initialized dynptrs (eg
bpf_dynptr_read + bpf_dynptr_write which are added later in this
patchset), the verifier enforces that the dynptr has been initialized
properly by checking that their corresponding stack slots have been
marked as STACK_DYNPTR.
The 6th patch in this patchset adds test cases that the verifier should
successfully reject, such as for example attempting to use a dynptr
after doing a direct write into it inside the bpf program.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20220523210712.3641569-2-joannelkoong@gmail.com
Diffstat (limited to 'include/uapi/linux/matroxfb.h')
0 files changed, 0 insertions, 0 deletions