leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

bpf: Add dynptr data slices

Browse Source 
This patch adds a new helper function

void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len);

which returns a pointer to the underlying data of a dynptr. *len*
must be a statically known value. The bpf program may access the returned
data slice as a normal buffer (eg can do direct reads and writes), since
the verifier associates the length with the returned pointer, and
enforces that no out of bounds accesses occur.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220523210712.3641569-6-joannelkoong@gmail.com
This commit is contained in:
Joanne Koong
2022-05-23 14:07:11 -07:00
committed by Andrii Nakryiko
parent 13bbbfbea7
commit 34d4ef5775
5 changed files with 76 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
tools/include/uapi/linux/bpf.h
View File

@@ -5238,6 +5238,17 @@ union bpf_attr {
* 0 on success, -E2BIG if *offset* + *len* exceeds the length
* of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst*
* is a read-only dynptr.
*
* void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len)
* Description
* Get a pointer to the underlying dynptr data.
*
* *len* must be a statically known value. The returned data slice
* is invalidated whenever the dynptr is invalidated.
* Return
* Pointer to the underlying dynptr data, NULL if the dynptr is
* read-only, if the dynptr is invalid, or if the offset and length
* is out of bounds.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -5443,6 +5454,7 @@ union bpf_attr {
FN(ringbuf_discard_dynptr), \
FN(dynptr_read), \
FN(dynptr_write), \
FN(dynptr_data), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper