diff --git a/include/compartment.h b/include/compartment.h index f94466e..ccd53ef 100644 --- a/include/compartment.h +++ b/include/compartment.h @@ -92,6 +92,7 @@ struct LibRelaMapping char *rela_name; void *rela_address; // address of relocation in compartment void *target_func_address; // address of actual function + unsigned short rela_type; // type of relocation unsigned short rela_sym_type; // type of underlying symbol unsigned short rela_sym_bind; // bind of underlying symbol }; diff --git a/src/compartment.c b/src/compartment.c index 9ee41f6..85c6d93 100644 --- a/src/compartment.c +++ b/src/compartment.c @@ -664,7 +664,7 @@ parse_lib_rela(Elf64_Shdr *rela_shdr, Elf64_Ehdr *lib_ehdr, int lib_fd, // Prepare TLS look-up function relocation (will be copied for each TLS // relocation entry static struct LibRelaMapping tls_lrm - = { NULL, 0x0, 0x0, STT_FUNC, STB_GLOBAL }; + = { NULL, 0x0, 0x0, -1, STT_FUNC, STB_GLOBAL }; // Log symbols that will need to be relocated eagerly at maptime Elf64_Rela curr_rela; @@ -675,7 +675,7 @@ parse_lib_rela(Elf64_Shdr *rela_shdr, Elf64_Ehdr *lib_ehdr, int lib_fd, size_t curr_rela_sym_idx = ELF64_R_SYM(curr_rela.r_info); size_t curr_rela_type = ELF64_R_TYPE(curr_rela.r_info); - struct LibRelaMapping lrm = { NULL, 0x0, 0x0, -1, -1 }; + struct LibRelaMapping lrm = { NULL, 0x0, 0x0, curr_rela_type, -1, -1 }; // XXX We handle `TLS` symbols differently. It seems the way // AARCH64 handles TLS variables is preferentially via @@ -736,11 +736,12 @@ parse_lib_rela(Elf64_Shdr *rela_shdr, Elf64_Ehdr *lib_ehdr, int lib_fd, // function relocation lrm.rela_address = curr_rela.r_offset + (char *) lib_dep->lib_mem_base + sizeof(void *); - memcpy( - new_relas + actual_relas, &lrm, sizeof(struct LibRelaMapping)); - - actual_relas += 1; - continue; + } + else if (curr_rela_type == R_AARCH64_TLS_TPREL64) + { + lrm.target_func_address = (char *) curr_rela.r_addend; + lrm.rela_address + = curr_rela.r_offset + (char *) lib_dep->lib_mem_base; } else { @@ -796,13 +797,9 @@ parse_lib_rela(Elf64_Shdr *rela_shdr, Elf64_Ehdr *lib_ehdr, int lib_fd, } lrm.rela_address = curr_rela.r_offset + (char *) lib_dep->lib_mem_base; - memcpy( - new_relas + actual_relas, &lrm, sizeof(struct LibRelaMapping)); - - actual_relas += 1; - continue; } - errx(1, "Unhandled relocation\n"); + memcpy(new_relas + actual_relas, &lrm, sizeof(struct LibRelaMapping)); + actual_relas += 1; } lib_dep->rela_maps = realloc(lib_dep->rela_maps, (lib_dep->rela_maps_count + actual_relas) @@ -890,12 +887,14 @@ resolve_rela_syms(struct Compartment *new_comp) continue; } - if (curr_rela_map->target_func_address != 0) + if (curr_rela_map->target_func_address != 0 + || curr_rela_map->rela_type == R_AARCH64_TLS_TPREL64) { continue; } - if (!strcmp(curr_rela_map->rela_name, tls_rtld_dropin)) + if (curr_rela_map->rela_name + && !strcmp(curr_rela_map->rela_name, tls_rtld_dropin)) { curr_rela_map->target_func_address = new_comp->tls_lookup_func; continue; @@ -961,6 +960,12 @@ find_lib_dep_sym_in_comp(const char *to_find, { for (size_t j = 0; j < comp_to_search->libs[i]->lib_syms_count; ++j) { + // Ignore non-symbol relocations + if (!comp_to_search->libs[i]->lib_syms[j].sym_name) + { + continue; + } + // TODO eyeball performance of this approach versus using `&&` // Ignore `LOCAL` bind symbols - they cannot be relocated against bool cond diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt index c1082b0..ce658b3 100644 --- a/tests/CMakeLists.txt +++ b/tests/CMakeLists.txt @@ -162,6 +162,7 @@ set(tests "simple_libc" "simple_malloc" "simple_open_write" + "simple_printf" "simple_static_var" "simple_syscall_getpid" "simple_syscall_write"