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bpf: fix use-after-free in bpf_uprobe_multi_link_attach()

PATCH Applied Oleg Nesterov 3 participants 3 messages Aug 13, 2024 – Sep 5, 2024

Subsystems (5)
Stable branch BPF Tracing BPF tracing +1 more subsystems
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Oleg Nesterov

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#0 lore raw

PATCH 1/1 bpf: fix use-after-free in bpf_uprobe_multi_link_attach()

If bpf_link_prime() fails, bpf_uprobe_multi_link_attach() goes to the error_free label and frees the array of bpf_uprobe's without calling bpf_uprobe_unregister().

This leaks bpf_uprobe->uprobe and worse, this frees bpf_uprobe->consumer without removing it from the uprobe->consumers list.

Cc [email protected]
Fixes 89ae89f53d20 ("bpf: Add multi uprobe link")
Reported-by [email protected]
Closes https://lore.kernel.org/all/[email protected]/ open here
Tested-by [email protected]
Acked-by Andrii Nakryiko <[email protected]>
Signed-off-by Oleg Nesterov <[email protected]>
---
 kernel/trace/bpf_trace.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
kernel/trace/bpf_trace.c +6 -3
index 4e391daafa64..90cd30e9723e 100644
@@ -3484,17 +3484,20 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 						    &uprobes[i].consumer);
 		if (IS_ERR(uprobes[i].uprobe)) {
 			err = PTR_ERR(uprobes[i].uprobe);
-			bpf_uprobe_unregister(uprobes, i);
-			goto error_free;
+			link->cnt = i;
+			goto error_unregister;
 		}
 	}
 
 	err = bpf_link_prime(&link->link, &link_primer);
 	if (err)
-		goto error_free;
+		goto error_unregister;
 
 	return bpf_link_settle(&link_primer);
 
+error_unregister:
+	bpf_uprobe_unregister(uprobes, link->cnt);
+
 error_free:
 	kvfree(uprobes);
 	kfree(link);
Signature · 1 line
2.25.1.362.g51ebf55
Acked-by on v1 1/1
#1 lore raw
Quoted 7 lines · Oleg Nesterov

If bpf_link_prime() fails, bpf_uprobe_multi_link_attach() goes to the error_free label and frees the array of bpf_uprobe's without calling bpf_uprobe_unregister().

This leaks bpf_uprobe->uprobe and worse, this frees bpf_uprobe->consumer without removing it from the uprobe->consumers list.

Quoted 7 lines
Cc [email protected]
Fixes 89ae89f53d20 ("bpf: Add multi uprobe link")
Reported-by [email protected]
Closes https://lore.kernel.org/all/[email protected]/ open here
Tested-by [email protected]
Acked-by Andrii Nakryiko <[email protected]>
Signed-off-by Oleg Nesterov <[email protected]>

thanks for fixing this

Acked-by Jiri Olsa <[email protected]>

jirka

Quoted 36 lines
---
 kernel/trace/bpf_trace.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
kernel/trace/bpf_trace.c +6 -3
index 4e391daafa64..90cd30e9723e 100644
@@ -3484,17 +3484,20 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 						    &uprobes[i].consumer);
 		if (IS_ERR(uprobes[i].uprobe)) {
 			err = PTR_ERR(uprobes[i].uprobe);
-			bpf_uprobe_unregister(uprobes, i);
-			goto error_free;
+			link->cnt = i;
+			goto error_unregister;
 		}
 	}
 
 	err = bpf_link_prime(&link->link, &link_primer);
 	if (err)
-		goto error_free;
+		goto error_unregister;
 
 	return bpf_link_settle(&link_primer);
 
+error_unregister:
+	bpf_uprobe_unregister(uprobes, link->cnt);
+
 error_free:
 	kvfree(uprobes);
 	kfree(link);
Signature · 1 line
2.25.1.362.g51ebf55
merge bot Applied
#2 lore raw

[tip: perf/core] bpf: Fix use-after-free in bpf_uprobe_multi_link_attach()

In reply to Oleg Nesterov
The following commit has been merged into the perf/core branch of tip:

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     5fe6e308abaea082c20fbf2aa5df8e14495622cf
Gitweb:        https://git.kernel.org/tip/5fe6e308abaea082c20fbf2aa5df8e14495622cf
Author:        Oleg Nesterov <[email protected]>
AuthorDate:    Tue, 13 Aug 2024 17:25:24 +02:00
Committer:     Peter Zijlstra <[email protected]>
CommitterDate: Thu, 05 Sep 2024 16:56:13 +02:00

bpf: Fix use-after-free in bpf_uprobe_multi_link_attach()

If bpf_link_prime() fails, bpf_uprobe_multi_link_attach() goes to the error_free label and frees the array of bpf_uprobe's without calling bpf_uprobe_unregister().

This leaks bpf_uprobe->uprobe and worse, this frees bpf_uprobe->consumer without removing it from the uprobe->consumers list.

Fixes 89ae89f53d20 ("bpf: Add multi uprobe link")
Closes https://lore.kernel.org/all/[email protected]/ open here
Reported-by [email protected]
Signed-off-by Oleg Nesterov <[email protected]>
Signed-off-by Peter Zijlstra (Intel) <[email protected]>
Acked-by Andrii Nakryiko <[email protected]>
Acked-by Jiri Olsa <[email protected]>
Tested-by [email protected]
Cc [email protected]
Link https://lore.kernel.org/r/[email protected] open here
---
 kernel/trace/bpf_trace.c |  9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
kernel/trace/bpf_trace.c +6 -3
index 4e391da..90cd30e 100644
@@ -3484,17 +3484,20 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 						    &uprobes[i].consumer);
 		if (IS_ERR(uprobes[i].uprobe)) {
 			err = PTR_ERR(uprobes[i].uprobe);
-			bpf_uprobe_unregister(uprobes, i);
-			goto error_free;
+			link->cnt = i;
+			goto error_unregister;
 		}
 	}
 
 	err = bpf_link_prime(&link->link, &link_primer);
 	if (err)
-		goto error_free;
+		goto error_unregister;
 
 	return bpf_link_settle(&link_primer);
 
+error_unregister:
+	bpf_uprobe_unregister(uprobes, link->cnt);
+
 error_free:
 	kvfree(uprobes);
 	kfree(link);