Hi,
On Tue, 2023-04-11 at 16:12 +0800, Ying Huang wrote:
> From: Ying Huang <ying.hu...@oss.cipunited.com>
>
> add some check related functions
> ---
> backends/mips_init.c | 3 +++
> backends/mips_symbol.c | 33 +++++++++++++++++++++++++++++++++
> libebl/eblrelocvaliduse.c | 8 ++++++--
> src/elflint.c | 23 ++++++++++++++++++++---
> 4 files changed, 62 insertions(+), 5 deletions(-)
>
> diff --git a/backends/mips_init.c b/backends/mips_init.c
> index 5bba822b..4c2f21b9 100644
> --- a/backends/mips_init.c
> +++ b/backends/mips_init.c
> @@ -51,6 +51,9 @@ mips_init (Elf *elf __attribute__ ((unused)),
> HOOK (eh, segment_type_name);
> HOOK (eh, dynamic_tag_check);
> HOOK (eh, dynamic_tag_name);
> + HOOK (eh, machine_section_flag_check);
> HOOK (eh, check_object_attribute);
> + HOOK (eh, check_special_symbol);
> + HOOK (eh, check_reloc_target_type);
> return eh;
> }
OK. But see below for hooking reloc_valid_use
> diff --git a/backends/mips_symbol.c b/backends/mips_symbol.c
> index e760d58d..8787fcee 100644
> --- a/backends/mips_symbol.c
> +++ b/backends/mips_symbol.c
> @@ -158,6 +158,39 @@ mips_section_type_name (int type,
> return NULL;
> }
>
> +bool
> +mips_check_reloc_target_type (Ebl *ebl __attribute__ ((unused)), Elf64_Word
> sh_type)
> +{
> + return (sh_type == SHT_MIPS_DWARF);
> +}
OK
> +/* Check whether given symbol's st_value and st_size are OK despite failing
> + normal checks. */
> +bool
> +mips_check_special_symbol (Elf *elf,
> + const GElf_Sym *sym __attribute__ ((unused)),
> + const char *name __attribute__ ((unused)),
> + const GElf_Shdr *destshdr)
> +{
> + size_t shstrndx;
> + if (elf_getshdrstrndx (elf, &shstrndx) != 0)
> + return false;
> + const char *sname = elf_strptr (elf, shstrndx, destshdr->sh_name);
> + if (sname == NULL)
> + return false;
> + return (strcmp (sname, ".got") == 0 || strcmp (sname, ".bss") == 0);
> +}
Could you add a comment why .got and .bss are special in this case?
> +/* Check whether SHF_MASKPROC flags are valid. */
> +bool
> +mips_machine_section_flag_check (GElf_Xword sh_flags)
> +{
> + return ((sh_flags &~ (SHF_MIPS_GPREL |
> + SHF_MIPS_MERGE |
> + SHF_MIPS_ADDR |
> + SHF_MIPS_STRINGS)) == 0);
> +}
OK. But see below for checking other SHF_MIPS flags.
> /* Check whether machine flags are valid. */
> bool
> mips_machine_flag_check (GElf_Word flags)
> diff --git a/libebl/eblrelocvaliduse.c b/libebl/eblrelocvaliduse.c
> index f0bed345..44b8d300 100644
> --- a/libebl/eblrelocvaliduse.c
> +++ b/libebl/eblrelocvaliduse.c
> @@ -32,10 +32,14 @@
> #endif
>
> #include <libeblP.h>
> -
> +#include <libelfP.h>
>
> bool
> ebl_reloc_valid_use (Ebl *ebl, int reloc)
> {
> - return ebl != NULL ? ebl->reloc_valid_use (ebl->elf, reloc) : false;
> + int relocNew = reloc;
> + GElf_Ehdr ehdr;
> + if(ebl->elf->class == ELFCLASS64 && gelf_getehdr(ebl->elf, &ehdr) != NULL
> && ehdr.e_machine == EM_MIPS)
> + relocNew = ELF64_MIPS_R_TYPE(reloc);
> + return ebl != NULL ? ebl->reloc_valid_use (ebl->elf, relocNew) : false;
> }
This should be a mips reloc_valid_use hook.
> diff --git a/src/elflint.c b/src/elflint.c
> index dd42dcb4..04f1ee92 100644
> --- a/src/elflint.c
> +++ b/src/elflint.c
> @@ -935,7 +935,10 @@ section [%2d] '%s': symbol %zu (%s): non-local symbol
> outside range described in
> }
>
> if (GELF_ST_TYPE (sym->st_info) == STT_SECTION
> - && GELF_ST_BIND (sym->st_info) != STB_LOCAL)
> + && GELF_ST_BIND (sym->st_info) != STB_LOCAL
> + && ehdr->e_machine != EM_MIPS
> + && strcmp (name, "_DYNAMIC_LINK") != 0
> + && strcmp (name, "_DYNAMIC_LINKING") != 0)
Could you add a comment here about both symbols not being local on
MIPS?
> ERROR (_("\
> section [%2d] '%s': symbol %zu (%s): non-local section symbol\n"),
> idx, section_name (ebl, idx), cnt, name);
> @@ -3789,6 +3792,12 @@ cannot get section header for section [%2zu] '%s':
> %s\n"),
> && ebl_bss_plt_p (ebl))
> good_type = SHT_NOBITS;
>
> + if (ehdr->e_machine == EM_MIPS
> + && (strstr(special_sections[s].name, ".debug") != NULL))
> + {
> + good_type = SHT_MIPS_DWARF;
> + }
OK. You don't need explicit brackets here
> /* In a debuginfo file, any normal section can be SHT_NOBITS.
> This is only invalid for DWARF sections and .shstrtab. */
> if (shdr->sh_type != good_type
> @@ -3953,8 +3962,16 @@ section [%2zu] '%s': size not multiple of entry
> size\n"),
> sh_flags &= ~(GElf_Xword) SHF_MASKPROC;
> }
> if (sh_flags & SHF_MASKOS)
> - if (gnuld)
> - sh_flags &= ~(GElf_Xword) SHF_GNU_RETAIN;
> + {
> + if (gnuld)
> + sh_flags &= ~(GElf_Xword) SHF_GNU_RETAIN;
> + if (ehdr->e_machine == EM_MIPS)
> + {
> + if(sh_flags == SHF_MIPS_NOSTRIP || sh_flags == SHF_MIPS_LOCAL
> + || sh_flags == SHF_MIPS_NAMES || sh_flags == SHF_MIPS_NODUPE)
> + sh_flags &= ~shdr->sh_flags;
> + }
> + }
> if (sh_flags != 0)
> ERROR (_("section [%2zu] '%s' contains unknown flag(s)"
> " %#" PRIx64 "\n"),
Can this be checked with the machine_section_flag_check hook?
Thanks,
Mark
