diff mbox series

[v6,bpf-next,04/11] bpf: Protect probed address based on kptr_restrict setting

Message ID 20230628115329.248450-5-laoar.shao@gmail.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series bpf: Support ->fill_link_info for kprobe_multi and perf_event links | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next, async
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: 12 this patch: 12
netdev/cc_maintainers success CCed 4 of 4 maintainers
netdev/build_clang success Errors and warnings before: 10 this patch: 10
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 12 this patch: 12
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 11 lines checked
netdev/kdoc success Errors and warnings before: 2 this patch: 2
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-PR success PR summary
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bpf/vmtest-bpf-next-VM_Test-15 success Logs for test_progs_no_alu32 on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-26 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-12 success Logs for test_progs on s390x with gcc
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Commit Message

Yafang Shao June 28, 2023, 11:53 a.m. UTC 
The probed address can be accessed by userspace through querying the task
file descriptor (fd). However, it is crucial to adhere to the kptr_restrict
setting and refrain from exposing the address if it is not permitted.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 kernel/trace/trace_kprobe.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 59cda19a9033..e4554dbfd113 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1551,7 +1551,10 @@  int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
 	} else {
 		*symbol = NULL;
 		*probe_offset = 0;
-		*probe_addr = (unsigned long)tk->rp.kp.addr;
+		if (kallsyms_show_value(current_cred()))
+			*probe_addr = (unsigned long)tk->rp.kp.addr;
+		else
+			*probe_addr = 0;
 	}
 	return 0;
 }