diff options
| author | Varun R Mallya <varunrmallya@gmail.com> | 2026-01-07 05:05:27 +0530 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2026-01-09 15:54:31 -0800 |
| commit | 5714ca8cba5ed736f3733663c446cbee63a10a64 (patch) | |
| tree | 90d84b1f46b7158b0d8873016e2def3959df6030 /tools | |
| parent | 4effccde0a0521b220c3585c9a0d8e677d345209 (diff) | |
libbpf: Fix OOB read in btf_dump_get_bitfield_value
When dumping bitfield data, btf_dump_get_bitfield_value() reads data
based on the underlying type's size (t->size). However, it does not
verify that the provided data buffer (data_sz) is large enough to
contain these bytes.
If btf_dump__dump_type_data() is called with a buffer smaller than
the type's size, this leads to an out-of-bounds read. This was
confirmed by AddressSanitizer in the linked issue.
Fix this by ensuring we do not read past the provided data_sz limit.
Fixes: a1d3cc3c5eca ("libbpf: Avoid use of __int128 in typed dump display")
Reported-by: Harrison Green <harrisonmichaelgreen@gmail.com>
Suggested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Varun R Mallya <varunrmallya@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260106233527.163487-1-varunrmallya@gmail.com
Closes: https://github.com/libbpf/libbpf/issues/928
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/lib/bpf/btf_dump.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 6388392f49a0..53c6624161d7 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -1762,9 +1762,18 @@ static int btf_dump_get_bitfield_value(struct btf_dump *d, __u16 left_shift_bits, right_shift_bits; const __u8 *bytes = data; __u8 nr_copy_bits; + __u8 start_bit, nr_bytes; __u64 num = 0; int i; + /* Calculate how many bytes cover the bitfield */ + start_bit = bits_offset % 8; + nr_bytes = (start_bit + bit_sz + 7) / 8; + + /* Bound check */ + if (data + nr_bytes > d->typed_dump->data_end) + return -E2BIG; + /* Maximum supported bitfield size is 64 bits */ if (t->size > 8) { pr_warn("unexpected bitfield size %d\n", t->size); |