diff mbox series

[bpf-next,v3,2/5] bpf: Limit the number of kprobes when attaching program to multiple kprobes

Message ID 20231215100708.2265609-3-houtao@huaweicloud.com (mailing list archive)
State Accepted
Commit d6d1e6c17cab2dcb7b8530c599f00e7de906d380
Delegated to: BPF
Headers show
Series bpf: Fix warnings in kvmalloc_node() | expand

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bpf/vmtest-bpf-next-VM_Test-37 success Logs for x86_64-llvm-18 / test (test_maps, false, 360) / test_maps on x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-38 success Logs for x86_64-llvm-18 / test (test_progs, false, 360) / test_progs on x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-39 success Logs for x86_64-llvm-18 / test (test_progs_cpuv4, false, 360) / test_progs_cpuv4 on x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-40 success Logs for x86_64-llvm-18 / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-41 success Logs for x86_64-llvm-18 / test (test_verifier, false, 360) / test_verifier on x86_64 with llvm-18
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netdev/series_format success Posting correctly formatted
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netdev/ynl success SINGLE THREAD; Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1132 this patch: 1132
netdev/cc_maintainers fail 1 blamed authors not CCed: mhiramat@kernel.org; 4 maintainers not CCed: mhiramat@kernel.org mathieu.desnoyers@efficios.com rostedt@goodmis.org linux-trace-kernel@vger.kernel.org
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netdev/verify_fixes success Fixes tag looks correct
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netdev/checkpatch warning CHECK: Prefer using the BIT macro
netdev/build_clang_rust success No Rust files in patch. Skipping build
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Commit Message

Hou Tao Dec. 15, 2023, 10:07 a.m. UTC 
From: Hou Tao <houtao1@huawei.com>

An abnormally big cnt may also be assigned to kprobe_multi.cnt when
attaching multiple kprobes. It will trigger the following warning in
kvmalloc_node():

	if (unlikely(size > INT_MAX)) {
	    WARN_ON_ONCE(!(flags & __GFP_NOWARN));
	    return NULL;
	}

Fix the warning by limiting the maximal number of kprobes in
bpf_kprobe_multi_link_attach(). If the number of kprobes is greater than
MAX_KPROBE_MULTI_CNT, the attachment will fail and return -E2BIG.

Acked-by: Jiri Olsa <jolsa@kernel.org>
Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 kernel/trace/bpf_trace.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 75c05aea9fd9..97c0c49c40a0 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -43,6 +43,7 @@ 
 	rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex))
 
 #define MAX_UPROBE_MULTI_CNT (1U << 20)
+#define MAX_KPROBE_MULTI_CNT (1U << 20)
 
 #ifdef CONFIG_MODULES
 struct bpf_trace_module {
@@ -2972,6 +2973,8 @@  int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 	cnt = attr->link_create.kprobe_multi.cnt;
 	if (!cnt)
 		return -EINVAL;
+	if (cnt > MAX_KPROBE_MULTI_CNT)
+		return -E2BIG;
 
 	size = cnt * sizeof(*addrs);
 	addrs = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);