[v2] bpftool: fix potential NULL pointer dereferencing in prog_dump()

[PATCH v2] bpftool: fix potential NULL pointer dereferencing in prog_dump()

Amir Mohammadi posted 1 patch 5 days, 21 hours ago

Diff against v1 v3
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tools/bpf/bpftool/prog.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

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[PATCH v2] bpftool: fix potential NULL pointer dereferencing in prog_dump()

Posted by Amir Mohammadi 5 days, 21 hours ago

A NULL pointer dereference could occur if ksyms
is not properly checked before usage in the prog_dump() function.

Signed-off-by: Amir Mohammadi <amiremohamadi@yahoo.com>
---
 tools/bpf/bpftool/prog.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 2ff949ea8..e71be67f1 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -822,11 +822,18 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
 					printf("%s:\n", sym_name);
 				}
 
-				if (disasm_print_insn(img, lens[i], opcodes,
-						      name, disasm_opt, btf,
-						      prog_linfo, ksyms[i], i,
-						      linum))
-					goto exit_free;
+				if (ksyms) {
+					if (disasm_print_insn(img, lens[i], opcodes,
+							      name, disasm_opt, btf,
+							      prog_linfo, ksyms[i], i,
+							      linum))
+						goto exit_free;
+				} else {
+					if (disasm_print_insn(img, lens[i], opcodes,
+							      name, disasm_opt, btf,
+							      NULL, 0, 0, false))
+						goto exit_free;
+				}
 
 				img += lens[i];
 
-- 
2.42.0

RE: [PATCH v2] bpftool: fix potential NULL pointer dereferencing in prog_dump()

Posted by John Fastabend 21 hours ago

Amir Mohammadi wrote:
> A NULL pointer dereference could occur if ksyms
> is not properly checked before usage in the prog_dump() function.
> 
> Signed-off-by: Amir Mohammadi <amiremohamadi@yahoo.com>
> ---
>  tools/bpf/bpftool/prog.c | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)

LGTM but still needs a Fixes line.