diff mbox series

[bpf-next,v2,1/3] bpf: refine retval for bpf_get_task_stack helper

Message ID 20210416204704.2816874-2-davemarchevsky@fb.com (mailing list archive)
State Accepted
Delegated to: BPF
Headers show
Series bpf: refine retval for bpf_get_task_stack helper | expand

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netdev/source_inline success Was 0 now: 0
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netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 20 this patch: 20
netdev/kdoc success Errors and warnings before: 0 this patch: 0
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netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 7 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 20 this patch: 20
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Commit Message

Dave Marchevsky April 16, 2021, 8:47 p.m. UTC 
Verifier can constrain the min/max bounds of bpf_get_task_stack's return
value more tightly than the default tnum_unknown. Like bpf_get_stack,
return value is num bytes written into a caller-supplied buf, or error,
so do_refine_retval_range will work.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
---
 kernel/bpf/verifier.c | 1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 852541a435ef..348e97f77003 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5767,6 +5767,7 @@  static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
 
 	if (ret_type != RET_INTEGER ||
 	    (func_id != BPF_FUNC_get_stack &&
+	     func_id != BPF_FUNC_get_task_stack &&
 	     func_id != BPF_FUNC_probe_read_str &&
 	     func_id != BPF_FUNC_probe_read_kernel_str &&
 	     func_id != BPF_FUNC_probe_read_user_str))