diff mbox series

[bpf-next,v6,03/26] bpf: Fix copy_map_value, zero_map_value

Message ID 20221111193224.876706-4-memxor@gmail.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series Allocated objects, BPF linked lists | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count fail Series longer than 15 patches (and no cover letter)
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1362 this patch: 1362
netdev/cc_maintainers warning 8 maintainers not CCed: sdf@google.com kpsingh@kernel.org haoluo@google.com yhs@fb.com jolsa@kernel.org martin.lau@linux.dev song@kernel.org john.fastabend@gmail.com
netdev/build_clang success Errors and warnings before: 157 this patch: 157
netdev/module_param success Was 0 now: 0
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netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1352 this patch: 1352
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 16 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next-VM_Test-4 fail Logs for build for aarch64 with llvm-16
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bpf/vmtest-bpf-next-VM_Test-2 fail Logs for build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-3 fail Logs for build for aarch64 with llvm-16

Commit Message

Kumar Kartikeya Dwivedi Nov. 11, 2022, 7:32 p.m. UTC 
The current offset needs to also skip over the already copied region in
addition to the size of the next field. This case manifests where there
are gaps between adjacent special fields.

It was observed that for a map value with size 48, having fields at:
off:  0, 16, 32
size: 4, 16, 16

The current code does:

memcpy(dst + 0, src + 0, 0)
memcpy(dst + 4, src + 4, 12)
memcpy(dst + 20, src + 20, 12)
memcpy(dst + 36, src + 36, 12)

With the fix, it is done correctly as:

memcpy(dst + 0, src + 0, 0)
memcpy(dst + 4, src + 4, 12)
memcpy(dst + 32, src + 32, 0)
memcpy(dst + 48, src + 48, 0)

Fixes: 4d7d7f69f4b1 ("bpf: Adapt copy_map_value for multiple offset case")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 include/linux/bpf.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1a66a1df1af1..f08eb2d27de0 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -360,7 +360,7 @@  static inline void bpf_obj_memcpy(struct btf_field_offs *foffs,
 		u32 sz = next_off - curr_off;
 
 		memcpy(dst + curr_off, src + curr_off, sz);
-		curr_off += foffs->field_sz[i];
+		curr_off += foffs->field_sz[i] + sz;
 	}
 	memcpy(dst + curr_off, src + curr_off, size - curr_off);
 }
@@ -390,7 +390,7 @@  static inline void bpf_obj_memzero(struct btf_field_offs *foffs, void *dst, u32
 		u32 sz = next_off - curr_off;
 
 		memset(dst + curr_off, 0, sz);
-		curr_off += foffs->field_sz[i];
+		curr_off += foffs->field_sz[i] + sz;
 	}
 	memset(dst + curr_off, 0, size - curr_off);
 }