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From: Maxim Mikityanskiy <maxtram95@gmail.com>
To: Eduard Zingerman <eddyz87@gmail.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>, Mykola Lysenko <mykolal@fb.com>,
	Shuah Khan <shuah@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	bpf@vger.kernel.org, linux-kselftest@vger.kernel.org,
	netdev@vger.kernel.org, Maxim Mikityanskiy <maxim@isovalent.com>
Subject: [PATCH bpf-next 04/15] bpf: Make bpf_for_each_spilled_reg consider narrow spills
Date: Wed, 20 Dec 2023 23:40:02 +0200	[thread overview]
Message-ID: <20231220214013.3327288-5-maxtram95@gmail.com> (raw)
In-Reply-To: <20231220214013.3327288-1-maxtram95@gmail.com>

From: Maxim Mikityanskiy <maxim@isovalent.com>

Adjust the check in bpf_get_spilled_reg to take into account spilled
registers narrower than 64 bits. That allows find_equal_scalars to
properly adjust the range of all spilled registers that have the same
ID. Before this change, it was possible for a register and a spilled
register to have the same IDs but different ranges if the spill was
narrower than 64 bits and a range check was performed on the register.

Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
---
 include/linux/bpf_verifier.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index d07d857ca67f..e11baecbde68 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -453,7 +453,7 @@ struct bpf_verifier_state {
 
 #define bpf_get_spilled_reg(slot, frame, mask)				\
 	(((slot < frame->allocated_stack / BPF_REG_SIZE) &&		\
-	  ((1 << frame->stack[slot].slot_type[0]) & (mask))) \
+	  ((1 << frame->stack[slot].slot_type[BPF_REG_SIZE - 1]) & (mask))) \
 	 ? &frame->stack[slot].spilled_ptr : NULL)
 
 /* Iterate over 'frame', setting 'reg' to either NULL or a spilled register. */
-- 
2.42.1


  parent reply	other threads:[~2023-12-20 21:40 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-20 21:39 [PATCH bpf-next 00/15] Improvements for tracking scalars in the BPF verifier Maxim Mikityanskiy
2023-12-20 21:39 ` [PATCH bpf-next 01/15] selftests/bpf: Fix the u64_offset_to_skb_data test Maxim Mikityanskiy
2023-12-26  9:52   ` Shung-Hsi Yu
2023-12-26 10:38     ` Maxim Mikityanskiy
2023-12-26 13:22       ` Shung-Hsi Yu
2024-01-04  2:22   ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 02/15] bpf: make infinite loop detection in is_state_visited() exact Maxim Mikityanskiy
2023-12-20 21:40 ` [PATCH bpf-next 03/15] selftests/bpf: check if imprecise stack spills confuse infinite loop detection Maxim Mikityanskiy
2023-12-20 21:40 ` Maxim Mikityanskiy [this message]
2024-01-04  2:25   ` [PATCH bpf-next 04/15] bpf: Make bpf_for_each_spilled_reg consider narrow spills Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 05/15] selftests/bpf: Add a test case for 32-bit spill tracking Maxim Mikityanskiy
2024-01-04  2:25   ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 06/15] bpf: Add the assign_scalar_id_before_mov function Maxim Mikityanskiy
2024-01-04  2:26   ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 07/15] bpf: Add the get_reg_width function Maxim Mikityanskiy
2023-12-20 21:40 ` [PATCH bpf-next 08/15] bpf: Assign ID to scalars on spill Maxim Mikityanskiy
2023-12-25  3:15   ` Alexei Starovoitov
2023-12-25 21:11     ` Maxim Mikityanskiy
2023-12-25 21:26       ` Alexei Starovoitov
2024-01-04  2:26   ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 09/15] selftests/bpf: Test assigning " Maxim Mikityanskiy
2024-01-04  2:26   ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 10/15] bpf: Track spilled unbounded scalars Maxim Mikityanskiy
2024-01-04  2:26   ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 11/15] selftests/bpf: Test tracking " Maxim Mikityanskiy
2024-01-04  2:26   ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 12/15] bpf: Preserve boundaries and track scalars on narrowing fill Maxim Mikityanskiy
2023-12-26  5:29   ` Shung-Hsi Yu
2024-01-04  2:27   ` Eduard Zingerman
2024-01-05 17:48     ` Maxim Mikityanskiy
2023-12-20 21:40 ` [PATCH bpf-next 13/15] selftests/bpf: Add test cases for " Maxim Mikityanskiy
2024-01-04  2:26   ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 14/15] bpf: Optimize state pruning for spilled scalars Maxim Mikityanskiy
2023-12-20 21:40 ` [PATCH bpf-next 15/15] selftests/bpf: states pruning checks for scalar vs STACK_{MISC,ZERO} Maxim Mikityanskiy

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