perf dso: Extra validity checks that e_machine is valid
Better ensure a read e_machine is valid by checking the file appears like an ELF file and the read e_machine value is less than EM_NUM. This better avoids spurious e_machine values when looking for an e_machine in say a thread. Signed-off-by: Ian Rogers <irogers@google.com> Cc: Aditya Bodkhe <aditya.b1@linux.ibm.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Andi Kleen <ak@linux.intel.com> Cc: Athira Rajeev <atrajeev@linux.ibm.com> Cc: Chun-Tse Shao <ctshao@google.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Dr. David Alan Gilbert <linux@treblig.org> Cc: Guo Ren <guoren@kernel.org> Cc: Haibo Xu <haibo1.xu@intel.com> Cc: Howard Chu <howardchu95@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@linaro.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Garry <john.g.garry@oracle.com> Cc: Krzysztof Łopatowski <krzysztof.m.lopatowski@gmail.com> Cc: Leo Yan <leo.yan@linux.dev> Cc: Mark Wielaard <mark@klomp.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <pjw@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergei Trofimovich <slyich@gmail.com> Cc: Shimin Guo <shimin.guo@skydio.com> Cc: Stephen Brennan <stephen.s.brennan@oracle.com> Cc: Thomas Falcon <thomas.falcon@intel.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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@ -1236,17 +1236,28 @@ uint16_t dso__e_machine(struct dso *dso, struct machine *machine)
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try_to_open_dso(dso, machine);
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fd = dso__data(dso)->fd;
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if (fd >= 0) {
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_Static_assert(offsetof(Elf32_Ehdr, e_machine) == 18, "Unexpected offset");
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_Static_assert(offsetof(Elf64_Ehdr, e_machine) == 18, "Unexpected offset");
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if (dso__needs_swap(dso) == DSO_SWAP__UNSET) {
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unsigned char eidata;
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unsigned char e_ident[EI_NIDENT];
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if (pread(fd, &eidata, sizeof(eidata), EI_DATA) == sizeof(eidata))
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dso__swap_init(dso, eidata);
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_Static_assert(offsetof(Elf32_Ehdr, e_ident) == 0, "Unexpected offset");
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_Static_assert(offsetof(Elf64_Ehdr, e_ident) == 0, "Unexpected offset");
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if (pread(fd, &e_ident, sizeof(e_ident), 0) == sizeof(e_ident) &&
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memcmp(e_ident, ELFMAG, SELFMAG) == 0 &&
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e_ident[EI_CLASS] > ELFCLASSNONE && e_ident[EI_CLASS] < ELFCLASSNUM &&
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e_ident[EI_DATA] > ELFDATANONE && e_ident[EI_DATA] < ELFDATANUM &&
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e_ident[EI_VERSION] == EV_CURRENT) {
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_Static_assert(offsetof(Elf32_Ehdr, e_machine) == 18, "Unexpected offset");
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_Static_assert(offsetof(Elf64_Ehdr, e_machine) == 18, "Unexpected offset");
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if (dso__needs_swap(dso) == DSO_SWAP__UNSET)
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dso__swap_init(dso, e_ident[EI_DATA]);
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if (dso__needs_swap(dso) != DSO_SWAP__UNSET &&
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pread(fd, &e_machine, sizeof(e_machine), 18) == sizeof(e_machine) &&
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e_machine < EM_NUM)
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e_machine = DSO__SWAP(dso, uint16_t, e_machine);
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else
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e_machine = EM_NONE;
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}
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if (dso__needs_swap(dso) != DSO_SWAP__UNSET &&
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pread(fd, &e_machine, sizeof(e_machine), 18) == sizeof(e_machine))
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e_machine = DSO__SWAP(dso, uint16_t, e_machine);
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}
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mutex_unlock(dso__data_open_lock());
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return e_machine;
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