From: Ian Rogers irogers@google.com
[ Upstream commit 9f19aab47ced012eddef1e2bc96007efc7713b61 ]
The LLVM template is first echo-ed into command_out and then command_out executed. The echo surrounds the template with double quotes, however, the template itself may contain quotes. This is generally innocuous but in tools/perf/tests/bpf-script-test-prologue.c we see: ... SEC("func=null_lseek file->f_mode offset orig") ... where the first double quote ends the double quote of the echo, then the > redirects output into a file called f_mode.
To avoid this inadvertent behavior substitute redirects and similar characters to be ASCII control codes, then substitute the output in the echo back again.
Fixes: 5eab5a7ee032acaa ("perf llvm: Display eBPF compiling command in debug output") Signed-off-by: Ian Rogers irogers@google.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andrii Nakryiko andrii@kernel.org Cc: bpf@vger.kernel.org Cc: Ingo Molnar mingo@redhat.com Cc: Jiri Olsa jolsa@kernel.org Cc: llvm@lists.linux.dev Cc: Mark Rutland mark.rutland@arm.com Cc: Namhyung Kim namhyung@kernel.org Cc: Nathan Chancellor nathan@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Cc: Peter Zijlstra peterz@infradead.org Cc: Tom Rix trix@redhat.com Link: https://lore.kernel.org/r/20230105082609.344538-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/llvm-utils.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/llvm-utils.c b/tools/perf/util/llvm-utils.c index 2dc7970074196..a9e18bb1601c7 100644 --- a/tools/perf/util/llvm-utils.c +++ b/tools/perf/util/llvm-utils.c @@ -531,14 +531,37 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf,
pr_debug("llvm compiling command template: %s\n", template);
+ /* + * Below, substitute control characters for values that can cause the + * echo to misbehave, then substitute the values back. + */ err = -ENOMEM; - if (asprintf(&command_echo, "echo -n "%s"", template) < 0) + if (asprintf(&command_echo, "echo -n \a%s\a", template) < 0) goto errout;
+#define SWAP_CHAR(a, b) do { if (*p == a) *p = b; } while (0) + for (char *p = command_echo; *p; p++) { + SWAP_CHAR('<', '\001'); + SWAP_CHAR('>', '\002'); + SWAP_CHAR('"', '\003'); + SWAP_CHAR(''', '\004'); + SWAP_CHAR('|', '\005'); + SWAP_CHAR('&', '\006'); + SWAP_CHAR('\a', '"'); + } err = read_from_pipe(command_echo, (void **) &command_out, NULL); if (err) goto errout;
+ for (char *p = command_out; *p; p++) { + SWAP_CHAR('\001', '<'); + SWAP_CHAR('\002', '>'); + SWAP_CHAR('\003', '"'); + SWAP_CHAR('\004', '''); + SWAP_CHAR('\005', '|'); + SWAP_CHAR('\006', '&'); + } +#undef SWAP_CHAR pr_debug("llvm compiling command : %s\n", command_out);
err = read_from_pipe(template, &obj_buf, &obj_buf_sz);