bpftool: Fix readlink usage in get_fd_type
[ Upstream commit 0053f7d39d491b6138d7c526876d13885cbb65f1 ] The `readlink(path, buf, sizeof(buf))` call reads at most sizeof(buf) bytes and *does not* append null-terminator to buf. With respect to that, fix two pieces in get_fd_type: 1. Change the truncation check to contain sizeof(buf) rather than sizeof(path). 2. Append null-terminator to buf. Reported by Coverity. Signed-off-by: Viktor Malik <vmalik@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Quentin Monnet <qmo@kernel.org> Link: https://lore.kernel.org/bpf/20250129071857.75182-1-vmalik@redhat.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
committed by
Greg Kroah-Hartman
parent
0e8eb91a49
commit
38d906f1c5
@@ -461,10 +461,11 @@ int get_fd_type(int fd)
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p_err("can't read link type: %s", strerror(errno));
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return -1;
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}
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if (n == sizeof(path)) {
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if (n == sizeof(buf)) {
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p_err("can't read link type: path too long!");
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return -1;
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}
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buf[n] = '\0';
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if (strstr(buf, "bpf-map"))
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return BPF_OBJ_MAP;
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