Re: [PATCH] perf top: fix overflow in elf_sec__is_text
From: Namhyung Kim
Date: Tue Jun 22 2021 - 15:46:57 EST
Hi Riccardo,
On Mon, Jun 21, 2021 at 3:22 PM Riccardo Mancini <rickyman7@xxxxxxxxx> wrote:
>
> ASan reports a heap-buffer-overflow in elf_sec__is_text when using perf-top.
> The bug is caused by the fact that secstrs is built from runtime_ss, while
> shdr is built from syms_ss if shdr.sh_type != SHT_NOBITS. Therefore, they
> point to two different ELF files.
>
> This patch renames secstrs to secstrs_run and adds secstrs_sym, so that
> the correct secstrs is chosen depending on shdr.sh_type.
>
> $ ASAN_OPTIONS=abort_on_error=1:disable_coredump=0:unmap_shadow_on_exit=1 ./perf top
> =================================================================
> ==363148==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61300009add6 at pc 0x00000049875c bp 0x7f4f56446440 sp 0x7f4f56445bf0
> READ of size 1 at 0x61300009add6 thread T6
> #0 0x49875b in StrstrCheck(void*, char*, char const*, char const*) (/home/user/linux/tools/perf/perf+0x49875b)
> #1 0x4d13a2 in strstr (/home/user/linux/tools/perf/perf+0x4d13a2)
> #2 0xacae36 in elf_sec__is_text /home/user/linux/tools/perf/util/symbol-elf.c:176:9
> #3 0xac3ec9 in elf_sec__filter /home/user/linux/tools/perf/util/symbol-elf.c:187:9
> #4 0xac2c3d in dso__load_sym /home/user/linux/tools/perf/util/symbol-elf.c:1254:20
> #5 0x883981 in dso__load /home/user/linux/tools/perf/util/symbol.c:1897:9
> #6 0x8e6248 in map__load /home/user/linux/tools/perf/util/map.c:332:7
> #7 0x8e66e5 in map__find_symbol /home/user/linux/tools/perf/util/map.c:366:6
> #8 0x7f8278 in machine__resolve /home/user/linux/tools/perf/util/event.c:707:13
> #9 0x5f3d1a in perf_event__process_sample /home/user/linux/tools/perf/builtin-top.c:773:6
> #10 0x5f30e4 in deliver_event /home/user/linux/tools/perf/builtin-top.c:1197:3
> #11 0x908a72 in do_flush /home/user/linux/tools/perf/util/ordered-events.c:244:9
> #12 0x905fae in __ordered_events__flush /home/user/linux/tools/perf/util/ordered-events.c:323:8
> #13 0x9058db in ordered_events__flush /home/user/linux/tools/perf/util/ordered-events.c:341:9
> #14 0x5f19b1 in process_thread /home/user/linux/tools/perf/builtin-top.c:1109:7
> #15 0x7f4f6a21a298 in start_thread /usr/src/debug/glibc-2.33-16.fc34.x86_64/nptl/pthread_create.c:481:8
> #16 0x7f4f697d0352 in clone ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
>
> 0x61300009add6 is located 10 bytes to the right of 332-byte region [0x61300009ac80,0x61300009adcc)
> allocated by thread T6 here:
> #0 0x4f3f7f in malloc (/home/user/linux/tools/perf/perf+0x4f3f7f)
> #1 0x7f4f6a0a88d9 (/lib64/libelf.so.1+0xa8d9)
>
> Thread T6 created by T0 here:
> #0 0x464856 in pthread_create (/home/user/linux/tools/perf/perf+0x464856)
> #1 0x5f06e0 in __cmd_top /home/user/linux/tools/perf/builtin-top.c:1309:6
> #2 0x5ef19f in cmd_top /home/user/linux/tools/perf/builtin-top.c:1762:11
> #3 0x7b28c0 in run_builtin /home/user/linux/tools/perf/perf.c:313:11
> #4 0x7b119f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8
> #5 0x7b2423 in run_argv /home/user/linux/tools/perf/perf.c:409:2
> #6 0x7b0c19 in main /home/user/linux/tools/perf/perf.c:539:3
> #7 0x7f4f696f7b74 in __libc_start_main /usr/src/debug/glibc-2.33-16.fc34.x86_64/csu/../csu/libc-start.c:332:16
>
> SUMMARY: AddressSanitizer: heap-buffer-overflow (/home/user/linux/tools/perf/perf+0x49875b) in StrstrCheck(void*, char*, char const*, char const*)
> Shadow bytes around the buggy address:
> 0x0c268000b560: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x0c268000b570: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x0c268000b580: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x0c268000b590: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c268000b5a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> =>0x0c268000b5b0: 00 00 00 00 00 00 00 00 00 04[fa]fa fa fa fa fa
> 0x0c268000b5c0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
> 0x0c268000b5d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c268000b5e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c268000b5f0: 07 fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x0c268000b600: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
> Shadow byte legend (one shadow byte represents 8 application bytes):
> Addressable: 00
> Partially addressable: 01 02 03 04 05 06 07
> Heap left redzone: fa
> Freed heap region: fd
> Stack left redzone: f1
> Stack mid redzone: f2
> Stack right redzone: f3
> Stack after return: f5
> Stack use after scope: f8
> Global redzone: f9
> Global init order: f6
> Poisoned by user: f7
> Container overflow: fc
> Array cookie: ac
> Intra object redzone: bb
> ASan internal: fe
> Left alloca redzone: ca
> Right alloca redzone: cb
> Shadow gap: cc
> ==363148==ABORTING
>
> Signed-off-by: Riccardo Mancini <rickyman7@xxxxxxxxx>
> Suggested-by: Jiri Slaby <jirislaby@xxxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Thanks,
Namhyung
> ---
> tools/perf/util/symbol-elf.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> index 4c56aa837434..7a6e38bf87b0 100644
> --- a/tools/perf/util/symbol-elf.c
> +++ b/tools/perf/util/symbol-elf.c
> @@ -1081,7 +1081,7 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
> struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
> struct map *curr_map = map;
> struct dso *curr_dso = dso;
> - Elf_Data *symstrs, *secstrs;
> + Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;
> uint32_t nr_syms;
> int err = -1;
> uint32_t idx;
> @@ -1150,8 +1150,16 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
> if (sec_strndx == NULL)
> goto out_elf_end;
>
> - secstrs = elf_getdata(sec_strndx, NULL);
> - if (secstrs == NULL)
> + secstrs_run = elf_getdata(sec_strndx, NULL);
> + if (secstrs_run == NULL)
> + goto out_elf_end;
> +
> + sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
> + if (sec_strndx == NULL)
> + goto out_elf_end;
> +
> + secstrs_sym = elf_getdata(sec_strndx, NULL);
> + if (secstrs_sym == NULL)
> goto out_elf_end;
>
> nr_syms = shdr.sh_size / shdr.sh_entsize;
> @@ -1237,6 +1245,8 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
>
> gelf_getshdr(sec, &shdr);
>
> + secstrs = secstrs_sym;
> +
> /*
> * We have to fallback to runtime when syms' section header has
> * NOBITS set. NOBITS results in file offset (sh_offset) not
> @@ -1249,6 +1259,7 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
> goto out_elf_end;
>
> gelf_getshdr(sec, &shdr);
> + secstrs = secstrs_run;
> }
>
> if (is_label && !elf_sec__filter(&shdr, secstrs))
> --
> 2.23.0
>