diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c index 7841c86cd9c..3cd87020b03 100644 --- a/libbacktrace/elf.c +++ b/libbacktrace/elf.c @@ -5076,7 +5076,7 @@ elf_uncompress_chdr (struct backtrace_state *state, backtrace_error_callback error_callback, void *data, unsigned char **uncompressed, size_t *uncompressed_size) { - const b_elf_chdr *chdr; + b_elf_chdr chdr; char *alc; size_t alc_len; unsigned char *po; @@ -5088,27 +5088,30 @@ elf_uncompress_chdr (struct backtrace_state *state, if (compressed_size < sizeof (b_elf_chdr)) return 1; - chdr = (const b_elf_chdr *) compressed; + /* The lld linker can misalign a compressed section, so we can't safely read + the fields directly as we can for other ELF sections. See + https://github.com/ianlancetaylor/libbacktrace/pull/120. */ + memcpy (&chdr, compressed, sizeof (b_elf_chdr)); alc = NULL; alc_len = 0; - if (*uncompressed != NULL && *uncompressed_size >= chdr->ch_size) + if (*uncompressed != NULL && *uncompressed_size >= chdr.ch_size) po = *uncompressed; else { - alc_len = chdr->ch_size; + alc_len = chdr.ch_size; alc = backtrace_alloc (state, alc_len, error_callback, data); if (alc == NULL) return 0; po = (unsigned char *) alc; } - switch (chdr->ch_type) + switch (chdr.ch_type) { case ELFCOMPRESS_ZLIB: if (!elf_zlib_inflate_and_verify (compressed + sizeof (b_elf_chdr), compressed_size - sizeof (b_elf_chdr), - zdebug_table, po, chdr->ch_size)) + zdebug_table, po, chdr.ch_size)) goto skip; break; @@ -5116,7 +5119,7 @@ elf_uncompress_chdr (struct backtrace_state *state, if (!elf_zstd_decompress (compressed + sizeof (b_elf_chdr), compressed_size - sizeof (b_elf_chdr), (unsigned char *)zdebug_table, po, - chdr->ch_size)) + chdr.ch_size)) goto skip; break; @@ -5126,7 +5129,7 @@ elf_uncompress_chdr (struct backtrace_state *state, } *uncompressed = po; - *uncompressed_size = chdr->ch_size; + *uncompressed_size = chdr.ch_size; return 1; @@ -6876,8 +6879,8 @@ elf_add (struct backtrace_state *state, const char *filename, int descriptor, } } - // A debuginfo file may not have a useful .opd section, but we can use the - // one from the original executable. + /* A debuginfo file may not have a useful .opd section, but we can use the + one from the original executable. */ if (opd == NULL) opd = caller_opd;