From 85344cf524cccc7b8e10bf04ed38a0f586bffd10 Mon Sep 17 00:00:00 2001 From: Sumanth Korikkar Date: Tue, 21 Feb 2023 15:28:21 +0100 Subject: [PATCH] support ubsan for kpatch ubsan generates .data..Lubsan_data* sections as follows: 1. int main(int argc, char **argv) { int arr[100]; arr[101] = 1; printf("arr[101] = %d", arr[101]); return 0; } 2. 1a: 50 10 b0 ac st %r1,172(%r11) int arr[100]; arr[101] = 1; 1e: a7 39 00 65 lghi %r3,101 22: c0 20 00 00 00 00 larl %r2,22 24: R_390_PC32DBL .data..Lubsan_data1+0x2 28: c0 e5 00 00 00 00 brasl %r14,28 2a: R_390_PLT32DBL __ubsan_handle_out_of_bounds+0x2 3. 0000000000000000 <.data..Lubsan_data1>: 0: R_390_64 .rodata <=== source_location.location->file_name 8: 00 00 00 04 .long 0x00000004 <=== source_location.location->line c: 00 00 00 05 .long 0x00000005 <=== source_location.location->column 10: R_390_64 .data..Lubsan_type0 <== source_location->array_type 18: R_390_64 .data..Lubsan_type1 <=== source_location->index_type 4. Avoid correlating the *.data.Lubsan* sections. This means included function points to new *.data.Lubsan* sections. Signed-off-by: Sumanth Korikkar --- kpatch-build/create-diff-object.c | 13 +++++++++++++ kpatch-build/kpatch-elf.c | 12 ++++++++++++ kpatch-build/kpatch-elf.h | 1 + kpatch-build/lookup.c | 3 ++- 4 files changed, 28 insertions(+), 1 deletion(-) diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c index 707b0a9..454783a 100644 --- a/kpatch-build/create-diff-object.c +++ b/kpatch-build/create-diff-object.c @@ -1036,6 +1036,9 @@ static void kpatch_correlate_sections(struct list_head *seclist_orig, sec_patched->twin) continue; + if (is_ubsan_sec(sec_orig->name)) + continue; + if (is_special_static(is_rela_section(sec_orig) ? sec_orig->base->secsym : sec_orig->secsym)) @@ -1072,6 +1075,9 @@ static void kpatch_correlate_symbols(struct list_head *symlist_orig, sym_orig->type != sym_patched->type || sym_patched->twin) continue; + if (is_ubsan_sec(sym_orig->name)) + continue; + if (is_special_static(sym_orig)) continue; @@ -1547,6 +1553,13 @@ static void kpatch_replace_sections_syms(struct kpatch_elf *kelf) if (rela->sym->type != STT_SECTION || !rela->sym->sec) continue; + /* + * UBSAN data will be taken wholesale, no need to + * replace section symbols. + */ + if (is_ubsan_sec(rela->sym->name)) + continue; + /* * These sections don't have symbols associated with * them: diff --git a/kpatch-build/kpatch-elf.c b/kpatch-build/kpatch-elf.c index c7d12ec..405e0d3 100644 --- a/kpatch-build/kpatch-elf.c +++ b/kpatch-build/kpatch-elf.c @@ -587,6 +587,18 @@ bool is_local_sym(struct symbol *sym) return sym->bind == STB_LOCAL; } +bool is_ubsan_sec(const char *name) { + if (!strncmp(name, ".data.rel.local..Lubsan_data", 28) || + !strncmp(name, ".data..Lubsan_type", 18) || + !strncmp(name, ".Lubsan_data", 12) || + !strncmp(name, ".data..Lubsan_data", 18) || + !strncmp(name, ".rela.data..Lubsan_data", 23) || + !strncmp(name, ".rela.data.rel.local..Lubsan_data", 33)) + return true; + else + return false; +} + void print_strtab(char *buf, size_t size) { size_t i; diff --git a/kpatch-build/kpatch-elf.h b/kpatch-build/kpatch-elf.h index cd2900c..187b1d1 100644 --- a/kpatch-build/kpatch-elf.h +++ b/kpatch-build/kpatch-elf.h @@ -170,6 +170,7 @@ bool is_null_sym(struct symbol *sym); bool is_file_sym(struct symbol *sym); bool is_local_func_sym(struct symbol *sym); bool is_local_sym(struct symbol *sym); +bool is_ubsan_sec(const char *name); void print_strtab(char *buf, size_t size); void kpatch_create_shstrtab(struct kpatch_elf *kelf); diff --git a/kpatch-build/lookup.c b/kpatch-build/lookup.c index f2596b1..2ccc181 100644 --- a/kpatch-build/lookup.c +++ b/kpatch-build/lookup.c @@ -84,7 +84,8 @@ static bool maybe_discarded_sym(const char *name) !strncmp(name, "__func_stack_frame_non_standard_", 32) || strstr(name, "__addressable_") || strstr(name, "__UNIQUE_ID_") || - !strncmp(name, ".L.str", 6)) + !strncmp(name, ".L.str", 6) || + is_ubsan_sec(name)) return true; return false; -- 2.37.3